constraint.c

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/*
 * $Id: constraint.c 37512 2011-06-15 14:06:25Z campbellbarton $
 *
 * ***** BEGIN GPL LICENSE BLOCK *****
 *
 * This program is free software; you can redistribute it and/or
 * modify it under the terms of the GNU General Public License
 * as published by the Free Software Foundation; either version 2
 * of the License, or (at your option) any later version.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program; if not, write to the Free Software Foundation,
 * Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
 *
 * The Original Code is Copyright (C) 2001-2002 by NaN Holding BV.
 * All rights reserved.
 *
 * The Original Code is: all of this file.
 *
 * Contributor(s): 2007, Joshua Leung, major recode
 *
 * ***** END GPL LICENSE BLOCK *****
 */

#include <stdio.h> 
#include <stddef.h>
#include <string.h>
#include <math.h>
#include <float.h>

#include "MEM_guardedalloc.h"

#include "BLI_blenlib.h"
#include "BLI_listbase.h"
#include "BLI_math.h"
#include "BLI_editVert.h"
#include "BLI_utildefines.h"

#include "DNA_armature_types.h"
#include "DNA_constraint_types.h"
#include "DNA_modifier_types.h"
#include "DNA_object_types.h"
#include "DNA_action_types.h"
#include "DNA_curve_types.h"
#include "DNA_mesh_types.h"
#include "DNA_meshdata_types.h"
#include "DNA_lattice_types.h"
#include "DNA_scene_types.h"
#include "DNA_text_types.h"


#include "BKE_action.h"
#include "BKE_anim.h" /* for the curve calculation part */
#include "BKE_armature.h"
#include "BKE_blender.h"
#include "BKE_constraint.h"
#include "BKE_displist.h"
#include "BKE_deform.h"
#include "BKE_DerivedMesh.h"    /* for geometry targets */
#include "BKE_cdderivedmesh.h" /* for geometry targets */
#include "BKE_object.h"
#include "BKE_ipo.h"
#include "BKE_global.h"
#include "BKE_library.h"
#include "BKE_idprop.h"
#include "BKE_shrinkwrap.h"
#include "BKE_mesh.h"

#ifdef WITH_PYTHON
#include "BPY_extern.h"
#endif

#ifndef M_PI
#define M_PI            3.14159265358979323846
#endif



/* ************************ Constraints - General Utilities *************************** */
/* These functions here don't act on any specific constraints, and are therefore should/will
 * not require any of the special function-pointers afforded by the relevant constraint 
 * type-info structs.
 */

/* -------------- Naming -------------- */

/* Find the first available, non-duplicate name for a given constraint */
void unique_constraint_name (bConstraint *con, ListBase *list)
{
        BLI_uniquename(list, con, "Const", '.', offsetof(bConstraint, name), sizeof(con->name));
}

/* ----------------- Evaluation Loop Preparation --------------- */

/* package an object/bone for use in constraint evaluation */
/* This function MEM_calloc's a bConstraintOb struct, that will need to be freed after evaluation */
bConstraintOb *constraints_make_evalob (Scene *scene, Object *ob, void *subdata, short datatype)
{
        bConstraintOb *cob;
        
        /* create regardless of whether we have any data! */
        cob= MEM_callocN(sizeof(bConstraintOb), "bConstraintOb");
        
        /* for system time, part of deglobalization, code nicer later with local time (ton) */
        cob->scene= scene;
        
        /* based on type of available data */
        switch (datatype) {
                case CONSTRAINT_OBTYPE_OBJECT:
                {
                        /* disregard subdata... calloc should set other values right */
                        if (ob) {
                                cob->ob = ob;
                                cob->type = datatype;
                                cob->rotOrder = EULER_ORDER_DEFAULT; // TODO: when objects have rotation order too, use that
                                copy_m4_m4(cob->matrix, ob->obmat);
                        }
                        else
                                unit_m4(cob->matrix);
                        
                        copy_m4_m4(cob->startmat, cob->matrix);
                }
                        break;
                case CONSTRAINT_OBTYPE_BONE:
                {
                        /* only set if we have valid bone, otherwise default */
                        if (ob && subdata) {
                                cob->ob = ob;
                                cob->pchan = (bPoseChannel *)subdata;
                                cob->type = datatype;
                                
                                if (cob->pchan->rotmode > 0) {
                                        /* should be some type of Euler order */
                                        cob->rotOrder= cob->pchan->rotmode; 
                                }
                                else {
                                        /* Quats, so eulers should just use default order */
                                        cob->rotOrder= EULER_ORDER_DEFAULT;
                                }
                                
                                /* matrix in world-space */
                                mul_m4_m4m4(cob->matrix, cob->pchan->pose_mat, ob->obmat);
                        }
                        else
                                unit_m4(cob->matrix);
                                
                        copy_m4_m4(cob->startmat, cob->matrix);
                }
                        break;
                        
                default: /* other types not yet handled */
                        unit_m4(cob->matrix);
                        unit_m4(cob->startmat);
                        break;
        }
        
        return cob;
}

/* cleanup after constraint evaluation */
void constraints_clear_evalob (bConstraintOb *cob)
{
        float delta[4][4], imat[4][4];
        
        /* prevent crashes */
        if (cob == NULL) 
                return;
        
        /* calculate delta of constraints evaluation */
        invert_m4_m4(imat, cob->startmat);
        mul_m4_m4m4(delta, imat, cob->matrix);
        
        /* copy matrices back to source */
        switch (cob->type) {
                case CONSTRAINT_OBTYPE_OBJECT:
                {
                        /* cob->ob might not exist! */
                        if (cob->ob) {
                                /* copy new ob-matrix back to owner */
                                copy_m4_m4(cob->ob->obmat, cob->matrix);
                                
                                /* copy inverse of delta back to owner */
                                invert_m4_m4(cob->ob->constinv, delta);
                        }
                }
                        break;
                case CONSTRAINT_OBTYPE_BONE:
                {
                        /* cob->ob or cob->pchan might not exist */
                        if (cob->ob && cob->pchan) {
                                /* copy new pose-matrix back to owner */
                                mul_m4_m4m4(cob->pchan->pose_mat, cob->matrix, cob->ob->imat);
                                
                                /* copy inverse of delta back to owner */
                                invert_m4_m4(cob->pchan->constinv, delta);
                        }
                }
                        break;
        }
        
        /* free tempolary struct */
        MEM_freeN(cob);
}

/* -------------- Space-Conversion API -------------- */

/* This function is responsible for the correct transformations/conversions 
 * of a matrix from one space to another for constraint evaluation.
 * For now, this is only implemented for Objects and PoseChannels.
 */
void constraint_mat_convertspace (Object *ob, bPoseChannel *pchan, float mat[][4], short from, short to)
{
        float tempmat[4][4];
        float diff_mat[4][4];
        float imat[4][4];
        
        /* prevent crashes in these unlikely events  */
        if (ob==NULL || mat==NULL) return;
        /* optimise trick - check if need to do anything */
        if (from == to) return;
        
        /* are we dealing with pose-channels or objects */
        if (pchan) {
                /* pose channels */
                switch (from) {
                        case CONSTRAINT_SPACE_WORLD: /* ---------- FROM WORLDSPACE ---------- */
                        {
                                /* world to pose */
                                invert_m4_m4(imat, ob->obmat);
                                copy_m4_m4(tempmat, mat);
                                mul_m4_m4m4(mat, tempmat, imat);
                                
                                /* use pose-space as stepping stone for other spaces... */
                                if (ELEM(to, CONSTRAINT_SPACE_LOCAL, CONSTRAINT_SPACE_PARLOCAL)) {
                                        /* call self with slightly different values */
                                        constraint_mat_convertspace(ob, pchan, mat, CONSTRAINT_SPACE_POSE, to);
                                }
                        }
                                break;
                        case CONSTRAINT_SPACE_POSE:     /* ---------- FROM POSESPACE ---------- */
                        {
                                /* pose to world */
                                if (to == CONSTRAINT_SPACE_WORLD) {
                                        copy_m4_m4(tempmat, mat);
                                        mul_m4_m4m4(mat, tempmat, ob->obmat);
                                }
                                /* pose to local */
                                else if (to == CONSTRAINT_SPACE_LOCAL) {
                                        if (pchan->bone) {
                                                if (pchan->parent) {
                                                        float offs_bone[4][4];
                                                                
                                                        /* construct offs_bone the same way it is done in armature.c */
                                                        copy_m4_m3(offs_bone, pchan->bone->bone_mat);
                                                        copy_v3_v3(offs_bone[3], pchan->bone->head);
                                                        offs_bone[3][1]+= pchan->bone->parent->length;
                                                        
                                                        if (pchan->bone->flag & BONE_HINGE) {
                                                                /* pose_mat = par_pose-space_location * chan_mat */
                                                                float tmat[4][4];
                                                                
                                                                /* the rotation of the parent restposition */
                                                                copy_m4_m4(tmat, pchan->bone->parent->arm_mat);
                                                                
                                                                /* the location of actual parent transform */
                                                                copy_v3_v3(tmat[3], offs_bone[3]);
                                                                offs_bone[3][0]= offs_bone[3][1]= offs_bone[3][2]= 0.0f;
                                                                mul_m4_v3(pchan->parent->pose_mat, tmat[3]);
                                                                
                                                                mul_m4_m4m4(diff_mat, offs_bone, tmat);
                                                                invert_m4_m4(imat, diff_mat);
                                                        }
                                                        else {
                                                                /* pose_mat = par_pose_mat * bone_mat * chan_mat */
                                                                mul_m4_m4m4(diff_mat, offs_bone, pchan->parent->pose_mat);
                                                                invert_m4_m4(imat, diff_mat);
                                                        }
                                                }
                                                else {
                                                        /* pose_mat = chan_mat * arm_mat */
                                                        invert_m4_m4(imat, pchan->bone->arm_mat);
                                                }
                                                
                                                copy_m4_m4(tempmat, mat);
                                                mul_m4_m4m4(mat, tempmat, imat);
                                        }
                                }
                                /* pose to local with parent */
                                else if (to == CONSTRAINT_SPACE_PARLOCAL) {
                                        if (pchan->bone) {
                                                invert_m4_m4(imat, pchan->bone->arm_mat);
                                                copy_m4_m4(tempmat, mat);
                                                mul_m4_m4m4(mat, tempmat, imat);
                                        }
                                }
                        }
                                break;
                        case CONSTRAINT_SPACE_LOCAL: /* ------------ FROM LOCALSPACE --------- */
                        {
                                /* local to pose - do inverse procedure that was done for pose to local */
                                if (pchan->bone) {
                                        /* we need the posespace_matrix = local_matrix + (parent_posespace_matrix + restpos) */                                         
                                        if (pchan->parent) {
                                                float offs_bone[4][4];
                                                
                                                /* construct offs_bone the same way it is done in armature.c */
                                                copy_m4_m3(offs_bone, pchan->bone->bone_mat);
                                                copy_v3_v3(offs_bone[3], pchan->bone->head);
                                                offs_bone[3][1]+= pchan->bone->parent->length;
                                                
                                                if (pchan->bone->flag & BONE_HINGE) {
                                                        /* pose_mat = par_pose-space_location * chan_mat */
                                                        float tmat[4][4];
                                                        
                                                        /* the rotation of the parent restposition */
                                                        copy_m4_m4(tmat, pchan->bone->parent->arm_mat);
                                                        
                                                        /* the location of actual parent transform */
                                                        copy_v3_v3(tmat[3], offs_bone[3]);
                                                        zero_v3(offs_bone[3]);
                                                        mul_m4_v3(pchan->parent->pose_mat, tmat[3]);
                                                        
                                                        mul_m4_m4m4(diff_mat, offs_bone, tmat);
                                                        copy_m4_m4(tempmat, mat);
                                                        mul_m4_m4m4(mat, tempmat, diff_mat);
                                                }
                                                else {
                                                        /* pose_mat = par_pose_mat * bone_mat * chan_mat */
                                                        mul_m4_m4m4(diff_mat, offs_bone, pchan->parent->pose_mat);
                                                        copy_m4_m4(tempmat, mat);
                                                        mul_m4_m4m4(mat, tempmat, diff_mat);
                                                }
                                        }
                                        else {
                                                copy_m4_m4(diff_mat, pchan->bone->arm_mat);
                                                
                                                copy_m4_m4(tempmat, mat);
                                                mul_m4_m4m4(mat, tempmat, diff_mat);
                                        }
                                }
                                
                                /* use pose-space as stepping stone for other spaces */
                                if (ELEM(to, CONSTRAINT_SPACE_WORLD, CONSTRAINT_SPACE_PARLOCAL)) {
                                        /* call self with slightly different values */
                                        constraint_mat_convertspace(ob, pchan, mat, CONSTRAINT_SPACE_POSE, to);
                                }                               
                        }
                                break;
                        case CONSTRAINT_SPACE_PARLOCAL: /* -------------- FROM LOCAL WITH PARENT ---------- */
                        {
                                /* local + parent to pose */
                                if (pchan->bone) {                                      
                                        copy_m4_m4(diff_mat, pchan->bone->arm_mat);
                                        copy_m4_m4(tempmat, mat);
                                        mul_m4_m4m4(mat, diff_mat, tempmat);
                                }
                                
                                /* use pose-space as stepping stone for other spaces */
                                if (ELEM(to, CONSTRAINT_SPACE_WORLD, CONSTRAINT_SPACE_LOCAL)) {
                                        /* call self with slightly different values */
                                        constraint_mat_convertspace(ob, pchan, mat, CONSTRAINT_SPACE_POSE, to);
                                }
                        }
                                break;
                }
        }
        else {
                /* objects */
                if (from==CONSTRAINT_SPACE_WORLD && to==CONSTRAINT_SPACE_LOCAL) {
                        /* check if object has a parent */
                        if (ob->parent) {
                                /* 'subtract' parent's effects from owner */
                                mul_m4_m4m4(diff_mat, ob->parentinv, ob->parent->obmat);
                                invert_m4_m4(imat, diff_mat);
                                copy_m4_m4(tempmat, mat);
                                mul_m4_m4m4(mat, tempmat, imat);
                        }
                        else {
                                /* Local space in this case will have to be defined as local to the owner's 
                                 * transform-property-rotated axes. So subtract this rotation component.
                                 */
                                object_to_mat4(ob, diff_mat);
                                normalize_m4(diff_mat);
                                zero_v3(diff_mat[3]);
                                
                                invert_m4_m4(imat, diff_mat);
                                copy_m4_m4(tempmat, mat);
                                mul_m4_m4m4(mat, tempmat, imat);
                        }
                }
                else if (from==CONSTRAINT_SPACE_LOCAL && to==CONSTRAINT_SPACE_WORLD) {
                        /* check that object has a parent - otherwise this won't work */
                        if (ob->parent) {
                                /* 'add' parent's effect back to owner */
                                copy_m4_m4(tempmat, mat);
                                mul_m4_m4m4(diff_mat, ob->parentinv, ob->parent->obmat);
                                mul_m4_m4m4(mat, tempmat, diff_mat);
                        }
                        else {
                                /* Local space in this case will have to be defined as local to the owner's 
                                 * transform-property-rotated axes. So add back this rotation component.
                                 */
                                object_to_mat4(ob, diff_mat);
                                normalize_m4(diff_mat);
                                zero_v3(diff_mat[3]);
                                
                                copy_m4_m4(tempmat, mat);
                                mul_m4_m4m4(mat, tempmat, diff_mat);
                        }
                }
        }
}

/* ------------ General Target Matrix Tools ---------- */

/* function that sets the given matrix based on given vertex group in mesh */
static void contarget_get_mesh_mat (Object *ob, const char *substring, float mat[][4])
{
        DerivedMesh *dm = NULL;
        Mesh *me= ob->data;
        EditMesh *em = BKE_mesh_get_editmesh(me);
        float vec[3] = {0.0f, 0.0f, 0.0f};
        float normal[3] = {0.0f, 0.0f, 0.0f}, plane[3];
        float imat[3][3], tmat[3][3];
        int dgroup;
        short freeDM = 0;
        
        /* initialize target matrix using target matrix */
        copy_m4_m4(mat, ob->obmat);
        
        /* get index of vertex group */
        dgroup = defgroup_name_index(ob, substring);
        if (dgroup < 0) return;
        
        /* get DerivedMesh */
        if (em) {
                /* target is in editmode, so get a special derived mesh */
                dm = CDDM_from_editmesh(em, ob->data);
                freeDM= 1;
        }
        else {
                /* when not in EditMode, use the 'final' derived mesh, depsgraph
                 * ensures we build with CD_MDEFORMVERT layer */
                dm = (DerivedMesh *)ob->derivedFinal;
        }
        
        /* only continue if there's a valid DerivedMesh */
        if (dm) {
                MDeformVert *dvert = dm->getVertDataArray(dm, CD_MDEFORMVERT);
                int numVerts = dm->getNumVerts(dm);
                int i, j, count = 0;
                float co[3], nor[3];
                
                /* check that dvert is a valid pointers (just in case) */
                if (dvert) {
                        /* get the average of all verts with that are in the vertex-group */
                        for (i = 0; i < numVerts; i++) {        
                                for (j = 0; j < dvert[i].totweight; j++) {
                                        /* does this vertex belong to nominated vertex group? */
                                        if (dvert[i].dw[j].def_nr == dgroup) {
                                                dm->getVertCo(dm, i, co);
                                                dm->getVertNo(dm, i, nor);
                                                add_v3_v3(vec, co);
                                                add_v3_v3(normal, nor);
                                                count++;
                                                break;
                                        }
                                        
                                }
                        }
                        
                        
                        /* calculate averages of normal and coordinates */
                        if (count > 0) {
                                mul_v3_fl(vec, 1.0f / count);
                                mul_v3_fl(normal, 1.0f / count);
                        }
                        
                        
                        /* derive the rotation from the average normal: 
                         *              - code taken from transform_manipulator.c, 
                         *                      calc_manipulator_stats, V3D_MANIP_NORMAL case
                         */
                        /*      we need the transpose of the inverse for a normal... */
                        copy_m3_m4(imat, ob->obmat);
                        
                        invert_m3_m3(tmat, imat);
                        transpose_m3(tmat);
                        mul_m3_v3(tmat, normal);
                        
                        normalize_v3(normal);
                        copy_v3_v3(plane, tmat[1]);
                        
                        copy_v3_v3(tmat[2], normal);
                        cross_v3_v3v3(tmat[0], normal, plane);
                        cross_v3_v3v3(tmat[1], tmat[2], tmat[0]);
                        
                        copy_m4_m3(mat, tmat);
                        normalize_m4(mat);
                        
                        
                        /* apply the average coordinate as the new location */
                        mul_v3_m4v3(mat[3], ob->obmat, vec);
                }
        }
        
        /* free temporary DerivedMesh created (in EditMode case) */
        if (dm && freeDM)
                dm->release(dm);
        if (em)
                BKE_mesh_end_editmesh(me, em);
}

/* function that sets the given matrix based on given vertex group in lattice */
static void contarget_get_lattice_mat (Object *ob, const char *substring, float mat[][4])
{
        Lattice *lt= (Lattice *)ob->data;
        
        DispList *dl = find_displist(&ob->disp, DL_VERTS);
        float *co = dl?dl->verts:NULL;
        BPoint *bp = lt->def;
        
        MDeformVert *dvert = lt->dvert;
        int tot_verts= lt->pntsu*lt->pntsv*lt->pntsw;
        float vec[3]= {0.0f, 0.0f, 0.0f}, tvec[3];
        int dgroup=0, grouped=0;
        int i, n;
        
        /* initialize target matrix using target matrix */
        copy_m4_m4(mat, ob->obmat);
        
        /* get index of vertex group */
        dgroup = defgroup_name_index(ob, substring);
        if (dgroup < 0) return;
        if (dvert == NULL) return;
        
        /* 1. Loop through control-points checking if in nominated vertex-group.
         * 2. If it is, add it to vec to find the average point.
         */
        for (i=0; i < tot_verts; i++, dvert++) {
                for (n= 0; n < dvert->totweight; n++) {
                        /* found match - vert is in vgroup */
                        if (dvert->dw[n].def_nr == dgroup) {
                                /* copy coordinates of point to temporary vector, then add to find average */
                                if (co)
                                        memcpy(tvec, co, 3*sizeof(float));
                                else
                                        memcpy(tvec, bp->vec, 3*sizeof(float));
                                        
                                add_v3_v3(vec, tvec);
                                grouped++;
                                
                                break;
                        }
                }
                
                /* advance pointer to coordinate data */
                if (co) co+= 3;
                else bp++;
        }
        
        /* find average location, then multiply by ob->obmat to find world-space location */
        if (grouped)
                mul_v3_fl(vec, 1.0f / grouped);
        mul_v3_m4v3(tvec, ob->obmat, vec);
        
        /* copy new location to matrix */
        copy_v3_v3(mat[3], tvec);
}

/* generic function to get the appropriate matrix for most target cases */
/* The cases where the target can be object data have not been implemented */
static void constraint_target_to_mat4 (Object *ob, const char *substring, float mat[][4], short from, short to, float headtail)
{
        /*      Case OBJECT */
        if (!strlen(substring)) {
                copy_m4_m4(mat, ob->obmat);
                constraint_mat_convertspace(ob, NULL, mat, from, to);
        }
        /*      Case VERTEXGROUP */
        /* Current method just takes the average location of all the points in the
         * VertexGroup, and uses that as the location value of the targets. Where 
         * possible, the orientation will also be calculated, by calculating an
         * 'average' vertex normal, and deriving the rotaation from that.
         *
         * NOTE: EditMode is not currently supported, and will most likely remain that
         *              way as constraints can only really affect things on object/bone level.
         */
        else if (ob->type == OB_MESH) {
                contarget_get_mesh_mat(ob, substring, mat);
                constraint_mat_convertspace(ob, NULL, mat, from, to);
        }
        else if (ob->type == OB_LATTICE) {
                contarget_get_lattice_mat(ob, substring, mat);
                constraint_mat_convertspace(ob, NULL, mat, from, to);
        }
        /*      Case BONE */
        else {
                bPoseChannel *pchan;
                
                pchan = get_pose_channel(ob->pose, substring);
                if (pchan) {
                        /* Multiply the PoseSpace accumulation/final matrix for this
                         * PoseChannel by the Armature Object's Matrix to get a worldspace
                         * matrix.
                         */
                        if (headtail < 0.000001f) {
                                /* skip length interpolation if set to head */
                                mul_m4_m4m4(mat, pchan->pose_mat, ob->obmat);
                        }
                        else {
                                float tempmat[4][4], loc[3];
                                
                                /* interpolate along length of bone */
                                interp_v3_v3v3(loc, pchan->pose_head, pchan->pose_tail, headtail);      
                                
                                /* use interpolated distance for subtarget */
                                copy_m4_m4(tempmat, pchan->pose_mat);   
                                copy_v3_v3(tempmat[3], loc);
                                
                                mul_m4_m4m4(mat, tempmat, ob->obmat);
                        }
                } 
                else
                        copy_m4_m4(mat, ob->obmat);
                        
                /* convert matrix space as required */
                constraint_mat_convertspace(ob, pchan, mat, from, to);
        }
}

/* ************************* Specific Constraints ***************************** */
/* Each constraint defines a set of functions, which will be called at the appropriate
 * times. In addition to this, each constraint should have a type-info struct, where
 * its functions are attached for use. 
 */
 
/* Template for type-info data:
 *      - make a copy of this when creating new constraints, and just change the functions
 *        pointed to as necessary
 *      - although the naming of functions doesn't matter, it would help for code
 *        readability, to follow the same naming convention as is presented here
 *      - any functions that a constraint doesn't need to define, don't define
 *        for such cases, just use NULL 
 *      - these should be defined after all the functions have been defined, so that
 *        forward-definitions/prototypes don't need to be used!
 *      - keep this copy #if-def'd so that future constraints can get based off this
 */
#if 0
static bConstraintTypeInfo CTI_CONSTRNAME = {
        CONSTRAINT_TYPE_CONSTRNAME, /* type */
        sizeof(bConstrNameConstraint), /* size */
        "ConstrName", /* name */
        "bConstrNameConstraint", /* struct name */
        constrname_free, /* free data */
        constrname_relink, /* relink data */
        constrname_id_looper, /* id looper */
        constrname_copy, /* copy data */
        constrname_new_data, /* new data */
        constrname_get_tars, /* get constraint targets */
        constrname_flush_tars, /* flush constraint targets */
        constrname_get_tarmat, /* get target matrix */
        constrname_evaluate /* evaluate */
};
#endif

/* This function should be used for the get_target_matrix member of all 
 * constraints that are not picky about what happens to their target matrix.
 */
static void default_get_tarmat (bConstraint *con, bConstraintOb *UNUSED(cob), bConstraintTarget *ct, float UNUSED(ctime))
{
        if (VALID_CONS_TARGET(ct))
                constraint_target_to_mat4(ct->tar, ct->subtarget, ct->matrix, CONSTRAINT_SPACE_WORLD, ct->space, con->headtail);
        else if (ct)
                unit_m4(ct->matrix);
}

/* This following macro should be used for all standard single-target *_get_tars functions 
 * to save typing and reduce maintainance woes.
 * (Hopefully all compilers will be happy with the lines with just a space on them. Those are
 *  really just to help this code easier to read)
 */
// TODO: cope with getting rotation order...
#define SINGLETARGET_GET_TARS(con, datatar, datasubtarget, ct, list) \
        { \
                ct= MEM_callocN(sizeof(bConstraintTarget), "tempConstraintTarget"); \
                 \
                ct->tar= datatar; \
                BLI_strncpy(ct->subtarget, datasubtarget, sizeof(ct->subtarget)); \
                ct->space= con->tarspace; \
                ct->flag= CONSTRAINT_TAR_TEMP; \
                 \
                if (ct->tar) { \
                        if ((ct->tar->type==OB_ARMATURE) && (ct->subtarget[0])) { \
                                bPoseChannel *pchan= get_pose_channel(ct->tar->pose, ct->subtarget); \
                                ct->type = CONSTRAINT_OBTYPE_BONE; \
                                ct->rotOrder= (pchan) ? (pchan->rotmode) : EULER_ORDER_DEFAULT; \
                        }\
                        else if (ELEM(ct->tar->type, OB_MESH, OB_LATTICE) && (ct->subtarget[0])) { \
                                ct->type = CONSTRAINT_OBTYPE_VERT; \
                                ct->rotOrder = EULER_ORDER_DEFAULT; \
                        } \
                        else {\
                                ct->type = CONSTRAINT_OBTYPE_OBJECT; \
                                ct->rotOrder= ct->tar->rotmode; \
                        } \
                } \
                 \
                BLI_addtail(list, ct); \
        }
        
/* This following macro should be used for all standard single-target *_get_tars functions 
 * to save typing and reduce maintainance woes. It does not do the subtarget related operations
 * (Hopefully all compilers will be happy with the lines with just a space on them. Those are
 *  really just to help this code easier to read)
 */
// TODO: cope with getting rotation order...
#define SINGLETARGETNS_GET_TARS(con, datatar, ct, list) \
        { \
                ct= MEM_callocN(sizeof(bConstraintTarget), "tempConstraintTarget"); \
                 \
                ct->tar= datatar; \
                ct->space= con->tarspace; \
                ct->flag= CONSTRAINT_TAR_TEMP; \
                 \
                if (ct->tar) ct->type = CONSTRAINT_OBTYPE_OBJECT; \
                 \
                BLI_addtail(list, ct); \
        }

/* This following macro should be used for all standard single-target *_flush_tars functions
 * to save typing and reduce maintainance woes.
 * Note: the pointer to ct will be changed to point to the next in the list (as it gets removed)
 * (Hopefully all compilers will be happy with the lines with just a space on them. Those are
 *  really just to help this code easier to read)
 */
#define SINGLETARGET_FLUSH_TARS(con, datatar, datasubtarget, ct, list, nocopy) \
        { \
                if (ct) { \
                        bConstraintTarget *ctn = ct->next; \
                        if (nocopy == 0) { \
                                datatar= ct->tar; \
                                BLI_strncpy(datasubtarget, ct->subtarget, sizeof(datasubtarget)); \
                                con->tarspace= (char)ct->space; \
                        } \
                         \
                        BLI_freelinkN(list, ct); \
                        ct= ctn; \
                } \
        }
        
/* This following macro should be used for all standard single-target *_flush_tars functions
 * to save typing and reduce maintainance woes. It does not do the subtarget related operations.
 * Note: the pointer to ct will be changed to point to the next in the list (as it gets removed)
 * (Hopefully all compilers will be happy with the lines with just a space on them. Those are
 *  really just to help this code easier to read)
 */
#define SINGLETARGETNS_FLUSH_TARS(con, datatar, ct, list, nocopy) \
        { \
                if (ct) { \
                        bConstraintTarget *ctn = ct->next; \
                        if (nocopy == 0) { \
                                datatar= ct->tar; \
                                con->tarspace= (char)ct->space; \
                        } \
                         \
                        BLI_freelinkN(list, ct); \
                        ct= ctn; \
                } \
        }
 
/* --------- ChildOf Constraint ------------ */

static void childof_new_data (void *cdata)
{
        bChildOfConstraint *data= (bChildOfConstraint *)cdata;
        
        data->flag = (CHILDOF_LOCX | CHILDOF_LOCY | CHILDOF_LOCZ |
                                        CHILDOF_ROTX |CHILDOF_ROTY | CHILDOF_ROTZ |
                                        CHILDOF_SIZEX | CHILDOF_SIZEY | CHILDOF_SIZEZ);
        unit_m4(data->invmat);
}

static void childof_id_looper (bConstraint *con, ConstraintIDFunc func, void *userdata)
{
        bChildOfConstraint *data= con->data;
        
        /* target only */
        func(con, (ID**)&data->tar, userdata);
}

static int childof_get_tars (bConstraint *con, ListBase *list)
{
        if (con && list) {
                bChildOfConstraint *data= con->data;
                bConstraintTarget *ct;
                
                /* standard target-getting macro for single-target constraints */
                SINGLETARGET_GET_TARS(con, data->tar, data->subtarget, ct, list)
                
                return 1;
        }
        
        return 0;
}

static void childof_flush_tars (bConstraint *con, ListBase *list, short nocopy)
{
        if (con && list) {
                bChildOfConstraint *data= con->data;
                bConstraintTarget *ct= list->first;
                
                /* the following macro is used for all standard single-target constraints */
                SINGLETARGET_FLUSH_TARS(con, data->tar, data->subtarget, ct, list, nocopy)
        }
}

static void childof_evaluate (bConstraint *con, bConstraintOb *cob, ListBase *targets)
{
        bChildOfConstraint *data= con->data;
        bConstraintTarget *ct= targets->first;
        
        /* only evaluate if there is a target */
        if (VALID_CONS_TARGET(ct)) {
                float parmat[4][4];
                
                /* simple matrix parenting */
                if(data->flag == CHILDOF_ALL) {
                        
                        /* multiply target (parent matrix) by offset (parent inverse) to get 
                         * the effect of the parent that will be exherted on the owner
                         */
                        mul_m4_m4m4(parmat, data->invmat, ct->matrix);
                        
                        /* now multiply the parent matrix by the owner matrix to get the 
                         * the effect of this constraint (i.e.  owner is 'parented' to parent)
                         */
                        mul_m4_m4m4(cob->matrix, cob->matrix, parmat);
                }
                else {
                        float invmat[4][4], tempmat[4][4];
                        float loc[3], eul[3], size[3];
                        float loco[3], eulo[3], sizo[3];
                        
                        /* get offset (parent-inverse) matrix */
                        copy_m4_m4(invmat, data->invmat);
                        
                        /* extract components of both matrices */
                        copy_v3_v3(loc, ct->matrix[3]);
                        mat4_to_eulO(eul, ct->rotOrder, ct->matrix);
                        mat4_to_size(size, ct->matrix);
                        
                        copy_v3_v3(loco, invmat[3]);
                        mat4_to_eulO(eulo, cob->rotOrder, invmat);
                        mat4_to_size(sizo, invmat);
                        
                        /* disable channels not enabled */
                        if (!(data->flag & CHILDOF_LOCX)) loc[0]= loco[0]= 0.0f;
                        if (!(data->flag & CHILDOF_LOCY)) loc[1]= loco[1]= 0.0f;
                        if (!(data->flag & CHILDOF_LOCZ)) loc[2]= loco[2]= 0.0f;
                        if (!(data->flag & CHILDOF_ROTX)) eul[0]= eulo[0]= 0.0f;
                        if (!(data->flag & CHILDOF_ROTY)) eul[1]= eulo[1]= 0.0f;
                        if (!(data->flag & CHILDOF_ROTZ)) eul[2]= eulo[2]= 0.0f;
                        if (!(data->flag & CHILDOF_SIZEX)) size[0]= sizo[0]= 1.0f;
                        if (!(data->flag & CHILDOF_SIZEY)) size[1]= sizo[1]= 1.0f;
                        if (!(data->flag & CHILDOF_SIZEZ)) size[2]= sizo[2]= 1.0f;
                        
                        /* make new target mat and offset mat */
                        loc_eulO_size_to_mat4(ct->matrix, loc, eul, size, ct->rotOrder);
                        loc_eulO_size_to_mat4(invmat, loco, eulo, sizo, cob->rotOrder);
                        
                        /* multiply target (parent matrix) by offset (parent inverse) to get 
                         * the effect of the parent that will be exherted on the owner
                         */
                        mul_m4_m4m4(parmat, invmat, ct->matrix);
                        
                        /* now multiply the parent matrix by the owner matrix to get the 
                         * the effect of this constraint (i.e.  owner is 'parented' to parent)
                         */
                        copy_m4_m4(tempmat, cob->matrix);
                        mul_m4_m4m4(cob->matrix, tempmat, parmat);

                        /* without this, changes to scale and rotation can change location
                         * of a parentless bone or a disconnected bone. Even though its set
                         * to zero above. */
                        if (!(data->flag & CHILDOF_LOCX)) cob->matrix[3][0]= tempmat[3][0];
                        if (!(data->flag & CHILDOF_LOCY)) cob->matrix[3][1]= tempmat[3][1];
                        if (!(data->flag & CHILDOF_LOCZ)) cob->matrix[3][2]= tempmat[3][2];     
                }
        }
}

/* XXX note, con->flag should be CONSTRAINT_SPACEONCE for bone-childof, patched in readfile.c */
static bConstraintTypeInfo CTI_CHILDOF = {
        CONSTRAINT_TYPE_CHILDOF, /* type */
        sizeof(bChildOfConstraint), /* size */
        "ChildOf", /* name */
        "bChildOfConstraint", /* struct name */
        NULL, /* free data */
        NULL, /* relink data */
        childof_id_looper, /* id looper */
        NULL, /* copy data */
        childof_new_data, /* new data */
        childof_get_tars, /* get constraint targets */
        childof_flush_tars, /* flush constraint targets */
        default_get_tarmat, /* get a target matrix */
        childof_evaluate /* evaluate */
};

/* -------- TrackTo Constraint ------- */

static void trackto_new_data (void *cdata)
{
        bTrackToConstraint *data= (bTrackToConstraint *)cdata;
        
        data->reserved1 = TRACK_Y;
        data->reserved2 = UP_Z;
}       

static void trackto_id_looper (bConstraint *con, ConstraintIDFunc func, void *userdata)
{
        bTrackToConstraint *data= con->data;
        
        /* target only */
        func(con, (ID**)&data->tar, userdata);
}

static int trackto_get_tars (bConstraint *con, ListBase *list)
{
        if (con && list) {
                bTrackToConstraint *data= con->data;
                bConstraintTarget *ct;
                
                /* standard target-getting macro for single-target constraints */
                SINGLETARGET_GET_TARS(con, data->tar, data->subtarget, ct, list)
                
                return 1;
        }
        
        return 0;
}

static void trackto_flush_tars (bConstraint *con, ListBase *list, short nocopy)
{
        if (con && list) {
                bTrackToConstraint *data= con->data;
                bConstraintTarget *ct= list->first;
                
                /* the following macro is used for all standard single-target constraints */
                SINGLETARGET_FLUSH_TARS(con, data->tar, data->subtarget, ct, list, nocopy)
        }
}


static int basis_cross (int n, int m)
{
        switch (n-m) {
                case 1: 
                case -2:
                        return 1;
                        
                case -1: 
                case 2:
                        return -1;
                        
                default:
                        return 0;
        }
}

static void vectomat (float *vec, float *target_up, short axis, short upflag, short flags, float m[][3])
{
        float n[3];
        float u[3]; /* vector specifying the up axis */
        float proj[3];
        float right[3];
        float neg = -1;
        int right_index;

        if (normalize_v3_v3(n, vec) == 0.0f) {
                n[0] = 0.0f;
                n[1] = 0.0f;
                n[2] = 1.0f;
        }
        if (axis > 2) axis -= 3;
        else negate_v3(n);

        /* n specifies the transformation of the track axis */
        if (flags & TARGET_Z_UP) { 
                /* target Z axis is the global up axis */
                copy_v3_v3(u, target_up);
        }
        else { 
                /* world Z axis is the global up axis */
                u[0] = 0;
                u[1] = 0;
                u[2] = 1;
        }

        /* project the up vector onto the plane specified by n */
        project_v3_v3v3(proj, u, n); /* first u onto n... */
        sub_v3_v3v3(proj, u, proj); /* then onto the plane */
        /* proj specifies the transformation of the up axis */

        if (normalize_v3(proj) == 0.0f) { /* degenerate projection */
                proj[0] = 0.0f;
                proj[1] = 1.0f;
                proj[2] = 0.0f;
        }

        /* Normalized cross product of n and proj specifies transformation of the right axis */
        cross_v3_v3v3(right, proj, n);
        normalize_v3(right);

        if (axis != upflag) {
                right_index = 3 - axis - upflag;
                neg = (float)basis_cross(axis, upflag);
                
                /* account for up direction, track direction */
                m[right_index][0] = neg * right[0];
                m[right_index][1] = neg * right[1];
                m[right_index][2] = neg * right[2];
                
                copy_v3_v3(m[upflag], proj);
                
                copy_v3_v3(m[axis], n);
        }
        /* identity matrix - don't do anything if the two axes are the same */
        else {
                unit_m3(m);
        }
}


static void trackto_evaluate (bConstraint *con, bConstraintOb *cob, ListBase *targets)
{
        bTrackToConstraint *data= con->data;
        bConstraintTarget *ct= targets->first;
        
        if (VALID_CONS_TARGET(ct)) {
                float size[3], vec[3];
                float totmat[3][3];
                float tmat[4][4];
                
                /* Get size property, since ob->size is only the object's own relative size, not its global one */
                mat4_to_size(size, cob->matrix);
                
                /* Clear the object's rotation */       
                cob->matrix[0][0]=size[0];
                cob->matrix[0][1]=0;
                cob->matrix[0][2]=0;
                cob->matrix[1][0]=0;
                cob->matrix[1][1]=size[1];
                cob->matrix[1][2]=0;
                cob->matrix[2][0]=0;
                cob->matrix[2][1]=0;
                cob->matrix[2][2]=size[2];
                
                /* targetmat[2] instead of ownermat[2] is passed to vectomat
                 * for backwards compatability it seems... (Aligorith)
                 */
                sub_v3_v3v3(vec, cob->matrix[3], ct->matrix[3]);
                vectomat(vec, ct->matrix[2], 
                                (short)data->reserved1, (short)data->reserved2, 
                                data->flags, totmat);
                
                copy_m4_m4(tmat, cob->matrix);
                mul_m4_m3m4(cob->matrix, totmat, tmat);
        }
}

static bConstraintTypeInfo CTI_TRACKTO = {
        CONSTRAINT_TYPE_TRACKTO, /* type */
        sizeof(bTrackToConstraint), /* size */
        "TrackTo", /* name */
        "bTrackToConstraint", /* struct name */
        NULL, /* free data */
        NULL, /* relink data */
        trackto_id_looper, /* id looper */
        NULL, /* copy data */
        trackto_new_data, /* new data */
        trackto_get_tars, /* get constraint targets */
        trackto_flush_tars, /* flush constraint targets */
        default_get_tarmat, /* get target matrix */
        trackto_evaluate /* evaluate */
};

/* --------- Inverse-Kinemetics --------- */

static void kinematic_new_data (void *cdata)
{
        bKinematicConstraint *data= (bKinematicConstraint *)cdata;
        
        data->weight= (float)1.0;
        data->orientweight= (float)1.0;
        data->iterations = 500;
        data->dist= (float)1.0;
        data->flag= CONSTRAINT_IK_TIP|CONSTRAINT_IK_STRETCH|CONSTRAINT_IK_POS;
}

static void kinematic_id_looper (bConstraint *con, ConstraintIDFunc func, void *userdata)
{
        bKinematicConstraint *data= con->data;
        
        /* chain target */
        func(con, (ID**)&data->tar, userdata);
        
        /* poletarget */
        func(con, (ID**)&data->poletar, userdata);
}

static int kinematic_get_tars (bConstraint *con, ListBase *list)
{
        if (con && list) {
                bKinematicConstraint *data= con->data;
                bConstraintTarget *ct;
                
                /* standard target-getting macro for single-target constraints is used twice here */
                SINGLETARGET_GET_TARS(con, data->tar, data->subtarget, ct, list)
                SINGLETARGET_GET_TARS(con, data->poletar, data->polesubtarget, ct, list)
                
                return 2;
        }
        
        return 0;
}

static void kinematic_flush_tars (bConstraint *con, ListBase *list, short nocopy)
{
        if (con && list) {
                bKinematicConstraint *data= con->data;
                bConstraintTarget *ct= list->first;
                
                /* the following macro is used for all standard single-target constraints */
                SINGLETARGET_FLUSH_TARS(con, data->tar, data->subtarget, ct, list, nocopy)
                SINGLETARGET_FLUSH_TARS(con, data->poletar, data->polesubtarget, ct, list, nocopy)
        }
}

static void kinematic_get_tarmat (bConstraint *con, bConstraintOb *cob, bConstraintTarget *ct, float UNUSED(ctime))
{
        bKinematicConstraint *data= con->data;
        
        if (VALID_CONS_TARGET(ct)) 
                constraint_target_to_mat4(ct->tar, ct->subtarget, ct->matrix, CONSTRAINT_SPACE_WORLD, ct->space, con->headtail);
        else if (ct) {
                if (data->flag & CONSTRAINT_IK_AUTO) {
                        Object *ob= cob->ob;
                        
                        if (ob == NULL) {
                                unit_m4(ct->matrix);
                        }
                        else {
                                float vec[3];
                                /* move grabtarget into world space */
                                mul_v3_m4v3(vec, ob->obmat, data->grabtarget);
                                copy_m4_m4(ct->matrix, ob->obmat);
                                copy_v3_v3(ct->matrix[3], vec);
                        }
                }
                else
                        unit_m4(ct->matrix);
        }
}

static bConstraintTypeInfo CTI_KINEMATIC = {
        CONSTRAINT_TYPE_KINEMATIC, /* type */
        sizeof(bKinematicConstraint), /* size */
        "IK", /* name */
        "bKinematicConstraint", /* struct name */
        NULL, /* free data */
        NULL, /* relink data */
        kinematic_id_looper, /* id looper */
        NULL, /* copy data */
        kinematic_new_data, /* new data */
        kinematic_get_tars, /* get constraint targets */
        kinematic_flush_tars, /* flush constraint targets */
        kinematic_get_tarmat, /* get target matrix */
        NULL /* evaluate - solved as separate loop */
};

/* -------- Follow-Path Constraint ---------- */

static void followpath_new_data (void *cdata)
{
        bFollowPathConstraint *data= (bFollowPathConstraint *)cdata;
        
        data->trackflag = TRACK_Y;
        data->upflag = UP_Z;
        data->offset = 0;
        data->followflag = 0;
}

static void followpath_id_looper (bConstraint *con, ConstraintIDFunc func, void *userdata)
{
        bFollowPathConstraint *data= con->data;
        
        /* target only */
        func(con, (ID**)&data->tar, userdata);
}

static int followpath_get_tars (bConstraint *con, ListBase *list)
{
        if (con && list) {
                bFollowPathConstraint *data= con->data;
                bConstraintTarget *ct;
                
                /* standard target-getting macro for single-target constraints without subtargets */
                SINGLETARGETNS_GET_TARS(con, data->tar, ct, list)
                
                return 1;
        }
        
        return 0;
}

static void followpath_flush_tars (bConstraint *con, ListBase *list, short nocopy)
{
        if (con && list) {
                bFollowPathConstraint *data= con->data;
                bConstraintTarget *ct= list->first;
                
                /* the following macro is used for all standard single-target constraints */
                SINGLETARGETNS_FLUSH_TARS(con, data->tar, ct, list, nocopy)
        }
}

static void followpath_get_tarmat (bConstraint *con, bConstraintOb *cob, bConstraintTarget *ct, float UNUSED(ctime))
{
        bFollowPathConstraint *data= con->data;
        
        if (VALID_CONS_TARGET(ct)) {
                Curve *cu= ct->tar->data;
                float vec[4], dir[3], radius;
                float totmat[4][4]= MAT4_UNITY;
                float curvetime;

                unit_m4(ct->matrix);

                /* note: when creating constraints that follow path, the curve gets the CU_PATH set now,
                 *              currently for paths to work it needs to go through the bevlist/displist system (ton) 
                 */
                
                /* only happens on reload file, but violates depsgraph still... fix! */
                if (cu->path==NULL || cu->path->data==NULL)
                        makeDispListCurveTypes(cob->scene, ct->tar, 0);
                
                if (cu->path && cu->path->data) {
                        float quat[4];
                        if ((data->followflag & FOLLOWPATH_STATIC) == 0) {
                                /* animated position along curve depending on time */
                                if (cob->scene)
                                        curvetime= bsystem_time(cob->scene, ct->tar, cu->ctime, 0.0) - data->offset;
                                else    
                                        curvetime= cu->ctime - data->offset;
                                
                                /* ctime is now a proper var setting of Curve which gets set by Animato like any other var that's animated,
                                 * but this will only work if it actually is animated... 
                                 *
                                 * we divide the curvetime calculated in the previous step by the length of the path, to get a time
                                 * factor, which then gets clamped to lie within 0.0 - 1.0 range
                                 */
                                curvetime /= cu->pathlen;
                                CLAMP(curvetime, 0.0f, 1.0f);
                        }
                        else {
                                /* fixed position along curve */
                                curvetime= data->offset_fac;
                        }
                        
                        if ( where_on_path(ct->tar, curvetime, vec, dir, (data->followflag & FOLLOWPATH_FOLLOW) ? quat : NULL, &radius, NULL) ) { /* quat_pt is quat or NULL*/
                                if (data->followflag & FOLLOWPATH_FOLLOW) {
#if 0
                                        float x1, q[4];
                                        vec_to_quat(quat, dir, (short)data->trackflag, (short)data->upflag);
                                        
                                        normalize_v3(dir);
                                        q[0]= (float)cos(0.5*vec[3]);
                                        x1= (float)sin(0.5*vec[3]);
                                        q[1]= -x1*dir[0];
                                        q[2]= -x1*dir[1];
                                        q[3]= -x1*dir[2];
                                        mul_qt_qtqt(quat, q, quat);
#else
                                        quat_apply_track(quat, data->trackflag, data->upflag);
#endif

                                        quat_to_mat4(totmat, quat);
                                }

                                if (data->followflag & FOLLOWPATH_RADIUS) {
                                        float tmat[4][4], rmat[4][4];
                                        scale_m4_fl(tmat, radius);
                                        mul_m4_m4m4(rmat, totmat, tmat);
                                        copy_m4_m4(totmat, rmat);
                                }
                                
                                copy_v3_v3(totmat[3], vec);
                                
                                mul_serie_m4(ct->matrix, ct->tar->obmat, totmat, NULL, NULL, NULL, NULL, NULL, NULL);
                        }
                }
        }
        else if (ct)
                unit_m4(ct->matrix);
}

static void followpath_evaluate (bConstraint *con, bConstraintOb *cob, ListBase *targets)
{
        bConstraintTarget *ct= targets->first;
        
        /* only evaluate if there is a target */
        if (VALID_CONS_TARGET(ct)) {
                float obmat[4][4];
                float size[3];
                bFollowPathConstraint *data= con->data;
                
                /* get Object transform (loc/rot/size) to determine transformation from path */
                // TODO: this used to be local at one point, but is probably more useful as-is
                copy_m4_m4(obmat, cob->matrix);
                
                /* get scaling of object before applying constraint */
                mat4_to_size(size, cob->matrix);
                
                /* apply targetmat - containing location on path, and rotation */
                mul_serie_m4(cob->matrix, ct->matrix, obmat, NULL, NULL, NULL, NULL, NULL, NULL);
                
                /* un-apply scaling caused by path */
                if ((data->followflag & FOLLOWPATH_RADIUS)==0) { /* XXX - assume that scale correction means that radius will have some scale error in it - Campbell */
                        float obsize[3];
                        
                        mat4_to_size( obsize,cob->matrix);
                        if (obsize[0])
                                mul_v3_fl(cob->matrix[0], size[0] / obsize[0]);
                        if (obsize[1])
                                mul_v3_fl(cob->matrix[1], size[1] / obsize[1]);
                        if (obsize[2])
                                mul_v3_fl(cob->matrix[2], size[2] / obsize[2]);
                }
        }
}

static bConstraintTypeInfo CTI_FOLLOWPATH = {
        CONSTRAINT_TYPE_FOLLOWPATH, /* type */
        sizeof(bFollowPathConstraint), /* size */
        "Follow Path", /* name */
        "bFollowPathConstraint", /* struct name */
        NULL, /* free data */
        NULL, /* relink data */
        followpath_id_looper, /* id looper */
        NULL, /* copy data */
        followpath_new_data, /* new data */
        followpath_get_tars, /* get constraint targets */
        followpath_flush_tars, /* flush constraint targets */
        followpath_get_tarmat, /* get target matrix */
        followpath_evaluate /* evaluate */
};

/* --------- Limit Location --------- */


static void loclimit_evaluate (bConstraint *con, bConstraintOb *cob, ListBase *UNUSED(targets))
{
        bLocLimitConstraint *data = con->data;
        
        if (data->flag & LIMIT_XMIN) {
                if (cob->matrix[3][0] < data->xmin)
                        cob->matrix[3][0] = data->xmin;
        }
        if (data->flag & LIMIT_XMAX) {
                if (cob->matrix[3][0] > data->xmax)
                        cob->matrix[3][0] = data->xmax;
        }
        if (data->flag & LIMIT_YMIN) {
                if (cob->matrix[3][1] < data->ymin)
                        cob->matrix[3][1] = data->ymin;
        }
        if (data->flag & LIMIT_YMAX) {
                if (cob->matrix[3][1] > data->ymax)
                        cob->matrix[3][1] = data->ymax;
        }
        if (data->flag & LIMIT_ZMIN) {
                if (cob->matrix[3][2] < data->zmin) 
                        cob->matrix[3][2] = data->zmin;
        }
        if (data->flag & LIMIT_ZMAX) {
                if (cob->matrix[3][2] > data->zmax)
                        cob->matrix[3][2] = data->zmax;
        }
}

static bConstraintTypeInfo CTI_LOCLIMIT = {
        CONSTRAINT_TYPE_LOCLIMIT, /* type */
        sizeof(bLocLimitConstraint), /* size */
        "Limit Location", /* name */
        "bLocLimitConstraint", /* struct name */
        NULL, /* free data */
        NULL, /* relink data */
        NULL, /* id looper */
        NULL, /* copy data */
        NULL, /* new data */
        NULL, /* get constraint targets */
        NULL, /* flush constraint targets */
        NULL, /* get target matrix */
        loclimit_evaluate /* evaluate */
};

/* -------- Limit Rotation --------- */

static void rotlimit_evaluate (bConstraint *con, bConstraintOb *cob, ListBase *UNUSED(targets))
{
        bRotLimitConstraint *data = con->data;
        float loc[3];
        float eul[3];
        float size[3];
        
        copy_v3_v3(loc, cob->matrix[3]);
        mat4_to_size(size, cob->matrix);

        mat4_to_eulO(eul, cob->rotOrder, cob->matrix);

        /* constraint data uses radians internally */
        
        /* limiting of euler values... */
        if (data->flag & LIMIT_XROT) {
                if (eul[0] < data->xmin) 
                        eul[0] = data->xmin;
                        
                if (eul[0] > data->xmax)
                        eul[0] = data->xmax;
        }
        if (data->flag & LIMIT_YROT) {
                if (eul[1] < data->ymin)
                        eul[1] = data->ymin;
                        
                if (eul[1] > data->ymax)
                        eul[1] = data->ymax;
        }
        if (data->flag & LIMIT_ZROT) {
                if (eul[2] < data->zmin)
                        eul[2] = data->zmin;
                        
                if (eul[2] > data->zmax)
                        eul[2] = data->zmax;
        }
                
        loc_eulO_size_to_mat4(cob->matrix, loc, eul, size, cob->rotOrder);
}

static bConstraintTypeInfo CTI_ROTLIMIT = {
        CONSTRAINT_TYPE_ROTLIMIT, /* type */
        sizeof(bRotLimitConstraint), /* size */
        "Limit Rotation", /* name */
        "bRotLimitConstraint", /* struct name */
        NULL, /* free data */
        NULL, /* relink data */
        NULL, /* id looper */
        NULL, /* copy data */
        NULL, /* new data */
        NULL, /* get constraint targets */
        NULL, /* flush constraint targets */
        NULL, /* get target matrix */
        rotlimit_evaluate /* evaluate */
};

/* --------- Limit Scaling --------- */


static void sizelimit_evaluate (bConstraint *con, bConstraintOb *cob, ListBase *UNUSED(targets))
{
        bSizeLimitConstraint *data = con->data;
        float obsize[3], size[3];
        
        mat4_to_size( size,cob->matrix);
        mat4_to_size( obsize,cob->matrix);
        
        if (data->flag & LIMIT_XMIN) {
                if (size[0] < data->xmin) 
                        size[0] = data->xmin;   
        }
        if (data->flag & LIMIT_XMAX) {
                if (size[0] > data->xmax) 
                        size[0] = data->xmax;
        }
        if (data->flag & LIMIT_YMIN) {
                if (size[1] < data->ymin) 
                        size[1] = data->ymin;   
        }
        if (data->flag & LIMIT_YMAX) {
                if (size[1] > data->ymax) 
                        size[1] = data->ymax;
        }
        if (data->flag & LIMIT_ZMIN) {
                if (size[2] < data->zmin) 
                        size[2] = data->zmin;   
        }
        if (data->flag & LIMIT_ZMAX) {
                if (size[2] > data->zmax) 
                        size[2] = data->zmax;
        }
        
        if (obsize[0]) 
                mul_v3_fl(cob->matrix[0], size[0]/obsize[0]);
        if (obsize[1]) 
                mul_v3_fl(cob->matrix[1], size[1]/obsize[1]);
        if (obsize[2]) 
                mul_v3_fl(cob->matrix[2], size[2]/obsize[2]);
}

static bConstraintTypeInfo CTI_SIZELIMIT = {
        CONSTRAINT_TYPE_SIZELIMIT, /* type */
        sizeof(bSizeLimitConstraint), /* size */
        "Limit Scaling", /* name */
        "bSizeLimitConstraint", /* struct name */
        NULL, /* free data */
        NULL, /* relink data */
        NULL, /* id looper */
        NULL, /* copy data */
        NULL, /* new data */
        NULL, /* get constraint targets */
        NULL, /* flush constraint targets */
        NULL, /* get target matrix */
        sizelimit_evaluate /* evaluate */
};

/* ----------- Copy Location ------------- */

static void loclike_new_data (void *cdata)
{
        bLocateLikeConstraint *data= (bLocateLikeConstraint *)cdata;
        
        data->flag = LOCLIKE_X|LOCLIKE_Y|LOCLIKE_Z;
}

static void loclike_id_looper (bConstraint *con, ConstraintIDFunc func, void *userdata)
{
        bLocateLikeConstraint *data= con->data;
        
        /* target only */
        func(con, (ID**)&data->tar, userdata);
}

static int loclike_get_tars (bConstraint *con, ListBase *list)
{
        if (con && list) {
                bLocateLikeConstraint *data= con->data;
                bConstraintTarget *ct;
                
                /* standard target-getting macro for single-target constraints */
                SINGLETARGET_GET_TARS(con, data->tar, data->subtarget, ct, list)
                
                return 1;
        }
        
        return 0;
}

static void loclike_flush_tars (bConstraint *con, ListBase *list, short nocopy)
{
        if (con && list) {
                bLocateLikeConstraint *data= con->data;
                bConstraintTarget *ct= list->first;
                
                /* the following macro is used for all standard single-target constraints */
                SINGLETARGET_FLUSH_TARS(con, data->tar, data->subtarget, ct, list, nocopy)
        }
}

static void loclike_evaluate (bConstraint *con, bConstraintOb *cob, ListBase *targets)
{
        bLocateLikeConstraint *data= con->data;
        bConstraintTarget *ct= targets->first;
        
        if (VALID_CONS_TARGET(ct)) {
                float offset[3] = {0.0f, 0.0f, 0.0f};
                
                if (data->flag & LOCLIKE_OFFSET)
                        copy_v3_v3(offset, cob->matrix[3]);
                        
                if (data->flag & LOCLIKE_X) {
                        cob->matrix[3][0] = ct->matrix[3][0];
                        
                        if (data->flag & LOCLIKE_X_INVERT) cob->matrix[3][0] *= -1;
                        cob->matrix[3][0] += offset[0];
                }
                if (data->flag & LOCLIKE_Y) {
                        cob->matrix[3][1] = ct->matrix[3][1];
                        
                        if (data->flag & LOCLIKE_Y_INVERT) cob->matrix[3][1] *= -1;
                        cob->matrix[3][1] += offset[1];
                }
                if (data->flag & LOCLIKE_Z) {
                        cob->matrix[3][2] = ct->matrix[3][2];
                        
                        if (data->flag & LOCLIKE_Z_INVERT) cob->matrix[3][2] *= -1;
                        cob->matrix[3][2] += offset[2];
                }
        }
}

static bConstraintTypeInfo CTI_LOCLIKE = {
        CONSTRAINT_TYPE_LOCLIKE, /* type */
        sizeof(bLocateLikeConstraint), /* size */
        "Copy Location", /* name */
        "bLocateLikeConstraint", /* struct name */
        NULL, /* free data */
        NULL, /* relink data */
        loclike_id_looper, /* id looper */
        NULL, /* copy data */
        loclike_new_data, /* new data */
        loclike_get_tars, /* get constraint targets */
        loclike_flush_tars, /* flush constraint targets */
        default_get_tarmat, /* get target matrix */
        loclike_evaluate /* evaluate */
};

/* ----------- Copy Rotation ------------- */

static void rotlike_new_data (void *cdata)
{
        bRotateLikeConstraint *data= (bRotateLikeConstraint *)cdata;
        
        data->flag = ROTLIKE_X|ROTLIKE_Y|ROTLIKE_Z;
}

static void rotlike_id_looper (bConstraint *con, ConstraintIDFunc func, void *userdata)
{
        bChildOfConstraint *data= con->data;
        
        /* target only */
        func(con, (ID**)&data->tar, userdata);
}

static int rotlike_get_tars (bConstraint *con, ListBase *list)
{
        if (con && list) {
                bRotateLikeConstraint *data= con->data;
                bConstraintTarget *ct;
                
                /* standard target-getting macro for single-target constraints */
                SINGLETARGET_GET_TARS(con, data->tar, data->subtarget, ct, list)
                
                return 1;
        }
        
        return 0;
}

static void rotlike_flush_tars (bConstraint *con, ListBase *list, short nocopy)
{
        if (con && list) {
                bRotateLikeConstraint *data= con->data;
                bConstraintTarget *ct= list->first;
                
                /* the following macro is used for all standard single-target constraints */
                SINGLETARGET_FLUSH_TARS(con, data->tar, data->subtarget, ct, list, nocopy)
        }
}

static void rotlike_evaluate (bConstraint *con, bConstraintOb *cob, ListBase *targets)
{
        bRotateLikeConstraint *data= con->data;
        bConstraintTarget *ct= targets->first;
        
        if (VALID_CONS_TARGET(ct)) {
                float   loc[3];
                float   eul[3], obeul[3];
                float   size[3];
                
                copy_v3_v3(loc, cob->matrix[3]);
                mat4_to_size(size, cob->matrix);
                
                /* to allow compatible rotations, must get both rotations in the order of the owner... */
                mat4_to_eulO(obeul, cob->rotOrder, cob->matrix);
                /* we must get compatible eulers from the beginning because some of them can be modified below (see bug #21875) */
                mat4_to_compatible_eulO(eul, obeul, cob->rotOrder, ct->matrix);
                
                if ((data->flag & ROTLIKE_X)==0)
                        eul[0] = obeul[0];
                else {
                        if (data->flag & ROTLIKE_OFFSET)
                                rotate_eulO(eul, cob->rotOrder, 'X', obeul[0]);
                        
                        if (data->flag & ROTLIKE_X_INVERT)
                                eul[0] *= -1;
                }
                
                if ((data->flag & ROTLIKE_Y)==0)
                        eul[1] = obeul[1];
                else {
                        if (data->flag & ROTLIKE_OFFSET)
                                rotate_eulO(eul, cob->rotOrder, 'Y', obeul[1]);
                        
                        if (data->flag & ROTLIKE_Y_INVERT)
                                eul[1] *= -1;
                }
                
                if ((data->flag & ROTLIKE_Z)==0)
                        eul[2] = obeul[2];
                else {
                        if (data->flag & ROTLIKE_OFFSET)
                                rotate_eulO(eul, cob->rotOrder, 'Z', obeul[2]);
                        
                        if (data->flag & ROTLIKE_Z_INVERT)
                                eul[2] *= -1;
                }
                
                /* good to make eulers compatible again, since we don't know how much they were changed above */
                compatible_eul(eul, obeul);
                loc_eulO_size_to_mat4(cob->matrix, loc, eul, size, cob->rotOrder);
        }
}

static bConstraintTypeInfo CTI_ROTLIKE = {
        CONSTRAINT_TYPE_ROTLIKE, /* type */
        sizeof(bRotateLikeConstraint), /* size */
        "Copy Rotation", /* name */
        "bRotateLikeConstraint", /* struct name */
        NULL, /* free data */
        NULL, /* relink data */
        rotlike_id_looper, /* id looper */
        NULL, /* copy data */
        rotlike_new_data, /* new data */
        rotlike_get_tars, /* get constraint targets */
        rotlike_flush_tars, /* flush constraint targets */
        default_get_tarmat, /* get target matrix */
        rotlike_evaluate /* evaluate */
};

/* ---------- Copy Scaling ---------- */

static void sizelike_new_data (void *cdata)
{
        bSizeLikeConstraint *data= (bSizeLikeConstraint *)cdata;
        
        data->flag = SIZELIKE_X|SIZELIKE_Y|SIZELIKE_Z;
}

static void sizelike_id_looper (bConstraint *con, ConstraintIDFunc func, void *userdata)
{
        bSizeLikeConstraint *data= con->data;
        
        /* target only */
        func(con, (ID**)&data->tar, userdata);
}

static int sizelike_get_tars (bConstraint *con, ListBase *list)
{
        if (con && list) {
                bSizeLikeConstraint *data= con->data;
                bConstraintTarget *ct;
                
                /* standard target-getting macro for single-target constraints */
                SINGLETARGET_GET_TARS(con, data->tar, data->subtarget, ct, list)
                
                return 1;
        }
        
        return 0;
}

static void sizelike_flush_tars (bConstraint *con, ListBase *list, short nocopy)
{
        if (con && list) {
                bSizeLikeConstraint *data= con->data;
                bConstraintTarget *ct= list->first;
                
                /* the following macro is used for all standard single-target constraints */
                SINGLETARGET_FLUSH_TARS(con, data->tar, data->subtarget, ct, list, nocopy)
        }
}

static void sizelike_evaluate (bConstraint *con, bConstraintOb *cob, ListBase *targets)
{
        bSizeLikeConstraint *data= con->data;
        bConstraintTarget *ct= targets->first;
        
        if (VALID_CONS_TARGET(ct)) {
                float obsize[3], size[3];
                
                mat4_to_size(size, ct->matrix);
                mat4_to_size(obsize, cob->matrix);
                
                if ((data->flag & SIZELIKE_X) && (obsize[0] != 0)) {
                        if (data->flag & SIZELIKE_OFFSET) {
                                size[0] += (obsize[0] - 1.0f);
                                mul_v3_fl(cob->matrix[0], size[0] / obsize[0]);
                        }
                        else
                                mul_v3_fl(cob->matrix[0], size[0] / obsize[0]);
                }
                if ((data->flag & SIZELIKE_Y) && (obsize[1] != 0)) {
                        if (data->flag & SIZELIKE_OFFSET) {
                                size[1] += (obsize[1] - 1.0f);
                                mul_v3_fl(cob->matrix[1], size[1] / obsize[1]);
                        }
                        else
                                mul_v3_fl(cob->matrix[1], size[1] / obsize[1]);
                }
                if ((data->flag & SIZELIKE_Z) && (obsize[2] != 0)) {
                        if (data->flag & SIZELIKE_OFFSET) {
                                size[2] += (obsize[2] - 1.0f);
                                mul_v3_fl(cob->matrix[2], size[2] / obsize[2]);
                        }
                        else
                                mul_v3_fl(cob->matrix[2], size[2] / obsize[2]);
                }
        }
}

static bConstraintTypeInfo CTI_SIZELIKE = {
        CONSTRAINT_TYPE_SIZELIKE, /* type */
        sizeof(bSizeLikeConstraint), /* size */
        "Copy Scale", /* name */
        "bSizeLikeConstraint", /* struct name */
        NULL, /* free data */
        NULL, /* relink data */
        sizelike_id_looper, /* id looper */
        NULL, /* copy data */
        sizelike_new_data, /* new data */
        sizelike_get_tars, /* get constraint targets */
        sizelike_flush_tars, /* flush constraint targets */
        default_get_tarmat, /* get target matrix */
        sizelike_evaluate /* evaluate */
};

/* ----------- Copy Transforms ------------- */

static void translike_id_looper (bConstraint *con, ConstraintIDFunc func, void *userdata)
{
        bTransLikeConstraint *data= con->data;
        
        /* target only */
        func(con, (ID**)&data->tar, userdata);
}

static int translike_get_tars (bConstraint *con, ListBase *list)
{
        if (con && list) {
                bTransLikeConstraint *data= con->data;
                bConstraintTarget *ct;
                
                /* standard target-getting macro for single-target constraints */
                SINGLETARGET_GET_TARS(con, data->tar, data->subtarget, ct, list)
                
                return 1;
        }
        
        return 0;
}

static void translike_flush_tars (bConstraint *con, ListBase *list, short nocopy)
{
        if (con && list) {
                bTransLikeConstraint *data= con->data;
                bConstraintTarget *ct= list->first;
                
                /* the following macro is used for all standard single-target constraints */
                SINGLETARGET_FLUSH_TARS(con, data->tar, data->subtarget, ct, list, nocopy)
        }
}

static void translike_evaluate (bConstraint *UNUSED(con), bConstraintOb *cob, ListBase *targets)
{
        bConstraintTarget *ct= targets->first;
        
        if (VALID_CONS_TARGET(ct)) {
                /* just copy the entire transform matrix of the target */
                copy_m4_m4(cob->matrix, ct->matrix);
        }
}

static bConstraintTypeInfo CTI_TRANSLIKE = {
        CONSTRAINT_TYPE_TRANSLIKE, /* type */
        sizeof(bTransLikeConstraint), /* size */
        "Copy Transforms", /* name */
        "bTransLikeConstraint", /* struct name */
        NULL, /* free data */
        NULL, /* relink data */
        translike_id_looper, /* id looper */
        NULL, /* copy data */
        NULL, /* new data */
        translike_get_tars, /* get constraint targets */
        translike_flush_tars, /* flush constraint targets */
        default_get_tarmat, /* get target matrix */
        translike_evaluate /* evaluate */
};

/* ---------- Maintain Volume ---------- */

static void samevolume_new_data (void *cdata)
{
        bSameVolumeConstraint *data= (bSameVolumeConstraint *)cdata;

        data->flag = SAMEVOL_Y;
        data->volume = 1.0f;
}

static void samevolume_evaluate (bConstraint *con, bConstraintOb *cob, ListBase *UNUSED(targets))
{
        bSameVolumeConstraint *data= con->data;

        float volume = data->volume;
        float fac = 1.0f;
        float obsize[3];

        mat4_to_size(obsize, cob->matrix);
        
        /* calculate normalising scale factor for non-essential values */
        if (obsize[data->flag] != 0) 
                fac = sqrtf(volume / obsize[data->flag]) / obsize[data->flag];
        
        /* apply scaling factor to the channels not being kept */
        switch (data->flag) {
                case SAMEVOL_X:
                        mul_v3_fl(cob->matrix[1], fac);
                        mul_v3_fl(cob->matrix[2], fac);
                        break;
                case SAMEVOL_Y:
                        mul_v3_fl(cob->matrix[0], fac);
                        mul_v3_fl(cob->matrix[2], fac);
                        break;
                case SAMEVOL_Z:
                        mul_v3_fl(cob->matrix[0], fac);
                        mul_v3_fl(cob->matrix[1], fac);
                        break;
        }
}

static bConstraintTypeInfo CTI_SAMEVOL = {
        CONSTRAINT_TYPE_SAMEVOL, /* type */
        sizeof(bSameVolumeConstraint), /* size */
        "Maintain Volume", /* name */
        "bSameVolumeConstraint", /* struct name */
        NULL, /* free data */
        NULL, /* relink data */
        NULL, /* id looper */
        NULL, /* copy data */
        samevolume_new_data, /* new data */
        NULL, /* get constraint targets */
        NULL, /* flush constraint targets */
        NULL, /* get target matrix */
        samevolume_evaluate /* evaluate */
};

/* ----------- Python Constraint -------------- */

static void pycon_free (bConstraint *con)
{
        bPythonConstraint *data= con->data;
        
        /* id-properties */
        IDP_FreeProperty(data->prop);
        MEM_freeN(data->prop);
        
        /* multiple targets */
        BLI_freelistN(&data->targets);
}       

static void pycon_relink (bConstraint *con)
{
        bPythonConstraint *data= con->data;
        
        ID_NEW(data->text);
}

static void pycon_copy (bConstraint *con, bConstraint *srccon)
{
        bPythonConstraint *pycon = (bPythonConstraint *)con->data;
        bPythonConstraint *opycon = (bPythonConstraint *)srccon->data;
        
        pycon->prop = IDP_CopyProperty(opycon->prop);
        BLI_duplicatelist(&pycon->targets, &opycon->targets);
}

static void pycon_new_data (void *cdata)
{
        bPythonConstraint *data= (bPythonConstraint *)cdata;
        
        /* everything should be set correctly by calloc, except for the prop->type constant.*/
        data->prop = MEM_callocN(sizeof(IDProperty), "PyConstraintProps");
        data->prop->type = IDP_GROUP;
}

static int pycon_get_tars (bConstraint *con, ListBase *list)
{
        if (con && list) {
                bPythonConstraint *data= con->data;
                
                list->first = data->targets.first;
                list->last = data->targets.last;
                
                return data->tarnum;
        }
        
        return 0;
}

static void pycon_id_looper (bConstraint *con, ConstraintIDFunc func, void *userdata)
{
        bPythonConstraint *data= con->data;
        bConstraintTarget *ct;
        
        /* targets */
        for (ct= data->targets.first; ct; ct= ct->next)
                func(con, (ID**)&ct->tar, userdata);
                
        /* script */
        func(con, (ID**)&data->text, userdata);
}

/* Whether this approach is maintained remains to be seen (aligorith) */
static void pycon_get_tarmat (bConstraint *con, bConstraintOb *cob, bConstraintTarget *ct, float UNUSED(ctime))
{
#ifdef WITH_PYTHON
        bPythonConstraint *data= con->data;
#endif

        if (VALID_CONS_TARGET(ct)) {
                /* special exception for curves - depsgraph issues */
                if (ct->tar->type == OB_CURVE) {
                        Curve *cu= ct->tar->data;
                        
                        /* this check is to make sure curve objects get updated on file load correctly.*/
                        if (cu->path==NULL || cu->path->data==NULL) /* only happens on reload file, but violates depsgraph still... fix! */
                                makeDispListCurveTypes(cob->scene, ct->tar, 0);                         
                }
                
                /* firstly calculate the matrix the normal way, then let the py-function override
                 * this matrix if it needs to do so
                 */
                constraint_target_to_mat4(ct->tar, ct->subtarget, ct->matrix, CONSTRAINT_SPACE_WORLD, ct->space, con->headtail);
                
                /* only execute target calculation if allowed */
#ifdef WITH_PYTHON
                if (G.f & G_SCRIPT_AUTOEXEC)
                        BPY_pyconstraint_target(data, ct);
#endif
        }
        else if (ct)
                unit_m4(ct->matrix);
}

static void pycon_evaluate (bConstraint *con, bConstraintOb *cob, ListBase *targets)
{
#ifndef WITH_PYTHON
        (void)con; (void)cob; (void)targets; /* unused */
        return;
#else
        bPythonConstraint *data= con->data;
        
        /* only evaluate in python if we're allowed to do so */
        if ((G.f & G_SCRIPT_AUTOEXEC)==0)  return;
        
/* currently removed, until I this can be re-implemented for multiple targets */
#if 0
        /* Firstly, run the 'driver' function which has direct access to the objects involved 
         * Technically, this is potentially dangerous as users may abuse this and cause dependency-problems,
         * but it also allows certain 'clever' rigging hacks to work.
         */
        BPY_pyconstraint_driver(data, cob, targets);
#endif
        
        /* Now, run the actual 'constraint' function, which should only access the matrices */
        BPY_pyconstraint_exec(data, cob, targets);
#endif /* WITH_PYTHON */
}

static bConstraintTypeInfo CTI_PYTHON = {
        CONSTRAINT_TYPE_PYTHON, /* type */
        sizeof(bPythonConstraint), /* size */
        "Script", /* name */
        "bPythonConstraint", /* struct name */
        pycon_free, /* free data */
        pycon_relink, /* relink data */
        pycon_id_looper, /* id looper */
        pycon_copy, /* copy data */
        pycon_new_data, /* new data */
        pycon_get_tars, /* get constraint targets */
        NULL, /* flush constraint targets */
        pycon_get_tarmat, /* get target matrix */
        pycon_evaluate /* evaluate */
};

/* -------- Action Constraint ----------- */

static void actcon_relink (bConstraint *con)
{
        bActionConstraint *data= con->data;
        ID_NEW(data->act);
}

static void actcon_new_data (void *cdata)
{
        bActionConstraint *data= (bActionConstraint *)cdata;
        
        /* set type to 20 (Loc X), as 0 is Rot X for backwards compatability */
        data->type = 20;
}

static void actcon_id_looper (bConstraint *con, ConstraintIDFunc func, void *userdata)
{
        bActionConstraint *data= con->data;
        
        /* target */
        func(con, (ID**)&data->tar, userdata);
        
        /* action */
        func(con, (ID**)&data->act, userdata);
}

static int actcon_get_tars (bConstraint *con, ListBase *list)
{
        if (con && list) {
                bActionConstraint *data= con->data;
                bConstraintTarget *ct;
                
                /* standard target-getting macro for single-target constraints */
                SINGLETARGET_GET_TARS(con, data->tar, data->subtarget, ct, list)
                
                return 1;
        }
        
        return 0;
}

static void actcon_flush_tars (bConstraint *con, ListBase *list, short nocopy)
{
        if (con && list) {
                bActionConstraint *data= con->data;
                bConstraintTarget *ct= list->first;
                
                /* the following macro is used for all standard single-target constraints */
                SINGLETARGET_FLUSH_TARS(con, data->tar, data->subtarget, ct, list, nocopy)
        }
}

static void actcon_get_tarmat (bConstraint *con, bConstraintOb *cob, bConstraintTarget *ct, float UNUSED(ctime))
{
        bActionConstraint *data = con->data;
        
        if (VALID_CONS_TARGET(ct)) {
                float tempmat[4][4], vec[3];
                float s, t;
                short axis;
                
                /* initialise return matrix */
                unit_m4(ct->matrix);
                
                /* get the transform matrix of the target */
                constraint_target_to_mat4(ct->tar, ct->subtarget, tempmat, CONSTRAINT_SPACE_WORLD, ct->space, con->headtail);
                
                /* determine where in transform range target is */
                /* data->type is mapped as follows for backwards compatability:
                 *      00,01,02        - rotation (it used to be like this)
                 *      10,11,12        - scaling
                 *      20,21,22        - location
                 */
                if (data->type < 10) {
                        /* extract rotation (is in whatever space target should be in) */
                        mat4_to_eul(vec, tempmat);
                        mul_v3_fl(vec, (float)(180.0/M_PI)); /* rad -> deg */
                        axis= data->type;
                }
                else if (data->type < 20) {
                        /* extract scaling (is in whatever space target should be in) */
                        mat4_to_size(vec, tempmat);
                        axis= data->type - 10;
                }
                else {
                        /* extract location */
                        copy_v3_v3(vec, tempmat[3]);
                        axis= data->type - 20;
                }
                
                /* Target defines the animation */
                s = (vec[axis]-data->min) / (data->max-data->min);
                CLAMP(s, 0, 1);
                t = (s * (data->end-data->start)) + data->start;
                
                if (G.f & G_DEBUG)
                        printf("do Action Constraint %s - Ob %s Pchan %s \n", con->name, cob->ob->id.name+2, (cob->pchan)?cob->pchan->name:NULL);
                
                /* Get the appropriate information from the action */
                if (cob->type == CONSTRAINT_OBTYPE_BONE) {
                        Object workob;
                        bPose *pose;
                        bPoseChannel *pchan, *tchan;
                        
                        /* make a temporary pose and evaluate using that */
                        pose = MEM_callocN(sizeof(bPose), "pose");
                        
                        /* make a copy of the bone of interest in the temp pose before evaluating action, so that it can get set 
                         *      - we need to manually copy over a few settings, including rotation order, otherwise this fails
                         */
                        pchan = cob->pchan;
                        
                        tchan= verify_pose_channel(pose, pchan->name);
                        tchan->rotmode= pchan->rotmode;
                        
                        /* evaluate action using workob (it will only set the PoseChannel in question) */
                        what_does_obaction(cob->ob, &workob, pose, data->act, pchan->name, t);
                        
                        /* convert animation to matrices for use here */
                        pchan_calc_mat(tchan);
                        copy_m4_m4(ct->matrix, tchan->chan_mat);
                        
                        /* Clean up */
                        free_pose(pose);
                }
                else if (cob->type == CONSTRAINT_OBTYPE_OBJECT) {
                        Object workob;
                        
                        /* evaluate using workob */
                        // FIXME: we don't have any consistent standards on limiting effects on object...
                        what_does_obaction(cob->ob, &workob, NULL, data->act, NULL, t);
                        object_to_mat4(&workob, ct->matrix);
                }
                else {
                        /* behaviour undefined... */
                        puts("Error: unknown owner type for Action Constraint");
                }
        }
}

static void actcon_evaluate (bConstraint *UNUSED(con), bConstraintOb *cob, ListBase *targets)
{
        bConstraintTarget *ct= targets->first;
        
        if (VALID_CONS_TARGET(ct)) {
                float temp[4][4];
                
                /* Nice and simple... we just need to multiply the matrices, as the get_target_matrix
                 * function has already taken care of everything else.
                 */
                copy_m4_m4(temp, cob->matrix);
                mul_m4_m4m4(cob->matrix, ct->matrix, temp);
        }
}

static bConstraintTypeInfo CTI_ACTION = {
        CONSTRAINT_TYPE_ACTION, /* type */
        sizeof(bActionConstraint), /* size */
        "Action", /* name */
        "bActionConstraint", /* struct name */
        NULL, /* free data */
        actcon_relink, /* relink data */
        actcon_id_looper, /* id looper */
        NULL, /* copy data */
        actcon_new_data, /* new data */
        actcon_get_tars, /* get constraint targets */
        actcon_flush_tars, /* flush constraint targets */
        actcon_get_tarmat, /* get target matrix */
        actcon_evaluate /* evaluate */
};

/* --------- Locked Track ---------- */

static void locktrack_new_data (void *cdata)
{
        bLockTrackConstraint *data= (bLockTrackConstraint *)cdata;
        
        data->trackflag = TRACK_Y;
        data->lockflag = LOCK_Z;
}       

static void locktrack_id_looper (bConstraint *con, ConstraintIDFunc func, void *userdata)
{
        bLockTrackConstraint *data= con->data;
        
        /* target only */
        func(con, (ID**)&data->tar, userdata);
}

static int locktrack_get_tars (bConstraint *con, ListBase *list)
{
        if (con && list) {
                bLockTrackConstraint *data= con->data;
                bConstraintTarget *ct;
                
                /* the following macro is used for all standard single-target constraints */
                SINGLETARGET_GET_TARS(con, data->tar, data->subtarget, ct, list)
                
                return 1;
        }
        
        return 0;
}

static void locktrack_flush_tars (bConstraint *con, ListBase *list, short nocopy)
{
        if (con && list) {
                bLockTrackConstraint *data= con->data;
                bConstraintTarget *ct= list->first;
                
                /* the following macro is used for all standard single-target constraints */
                SINGLETARGET_FLUSH_TARS(con, data->tar, data->subtarget, ct, list, nocopy)
        }
}

static void locktrack_evaluate (bConstraint *con, bConstraintOb *cob, ListBase *targets)
{
        bLockTrackConstraint *data= con->data;
        bConstraintTarget *ct= targets->first;
        
        if (VALID_CONS_TARGET(ct)) {
                float vec[3],vec2[3];
                float totmat[3][3];
                float tmpmat[3][3];
                float invmat[3][3];
                float tmat[4][4];
                float mdet;
                
                /* Vector object -> target */
                sub_v3_v3v3(vec, ct->matrix[3], cob->matrix[3]);
                switch (data->lockflag){
                case LOCK_X: /* LOCK X */
                {
                        switch (data->trackflag) {
                                case TRACK_Y: /* LOCK X TRACK Y */
                                {
                                        /* Projection of Vector on the plane */
                                        project_v3_v3v3(vec2, vec, cob->matrix[0]);
                                        sub_v3_v3v3(totmat[1], vec, vec2);
                                        normalize_v3(totmat[1]);
                                        
                                        /* the x axis is fixed */
                                        normalize_v3_v3(totmat[0], cob->matrix[0]);
                                        
                                        /* the z axis gets mapped onto a third orthogonal vector */
                                        cross_v3_v3v3(totmat[2], totmat[0], totmat[1]);
                                }
                                        break;
                                case TRACK_Z: /* LOCK X TRACK Z */
                                {
                                        /* Projection of Vector on the plane */
                                        project_v3_v3v3(vec2, vec, cob->matrix[0]);
                                        sub_v3_v3v3(totmat[2], vec, vec2);
                                        normalize_v3(totmat[2]);
                                        
                                        /* the x axis is fixed */
                                        normalize_v3_v3(totmat[0], cob->matrix[0]);
                                        
                                        /* the z axis gets mapped onto a third orthogonal vector */
                                        cross_v3_v3v3(totmat[1], totmat[2], totmat[0]);
                                }
                                        break;
                                case TRACK_nY: /* LOCK X TRACK -Y */
                                {
                                        /* Projection of Vector on the plane */
                                        project_v3_v3v3(vec2, vec, cob->matrix[0]);
                                        sub_v3_v3v3(totmat[1], vec, vec2);
                                        normalize_v3(totmat[1]);
                                        negate_v3(totmat[1]);
                                        
                                        /* the x axis is fixed */
                                        normalize_v3_v3(totmat[0], cob->matrix[0]);
                                        
                                        /* the z axis gets mapped onto a third orthogonal vector */
                                        cross_v3_v3v3(totmat[2], totmat[0], totmat[1]);
                                }
                                        break;
                                case TRACK_nZ: /* LOCK X TRACK -Z */
                                {
                                        /* Projection of Vector on the plane */
                                        project_v3_v3v3(vec2, vec, cob->matrix[0]);
                                        sub_v3_v3v3(totmat[2], vec, vec2);
                                        normalize_v3(totmat[2]);
                                        negate_v3(totmat[2]);
                                                
                                        /* the x axis is fixed */
                                        normalize_v3_v3(totmat[0], cob->matrix[0]);
                                                
                                        /* the z axis gets mapped onto a third orthogonal vector */
                                        cross_v3_v3v3(totmat[1], totmat[2], totmat[0]);
                                }
                                        break;
                                default:
                                {
                                        unit_m3(totmat);
                                }
                                        break;
                        }
                }
                        break;
                case LOCK_Y: /* LOCK Y */
                {
                        switch (data->trackflag) {
                                case TRACK_X: /* LOCK Y TRACK X */
                                {
                                        /* Projection of Vector on the plane */
                                        project_v3_v3v3(vec2, vec, cob->matrix[1]);
                                        sub_v3_v3v3(totmat[0], vec, vec2);
                                        normalize_v3(totmat[0]);
                                        
                                        /* the y axis is fixed */
                                        normalize_v3_v3(totmat[1], cob->matrix[1]);

                                        /* the z axis gets mapped onto a third orthogonal vector */
                                        cross_v3_v3v3(totmat[2], totmat[0], totmat[1]);
                                }
                                        break;
                                case TRACK_Z: /* LOCK Y TRACK Z */
                                {
                                        /* Projection of Vector on the plane */
                                        project_v3_v3v3(vec2, vec, cob->matrix[1]);
                                        sub_v3_v3v3(totmat[2], vec, vec2);
                                        normalize_v3(totmat[2]);
                                        
                                        /* the y axis is fixed */
                                        normalize_v3_v3(totmat[1], cob->matrix[1]);
                                        
                                        /* the z axis gets mapped onto a third orthogonal vector */
                                        cross_v3_v3v3(totmat[0], totmat[1], totmat[2]);
                                }
                                        break;
                                case TRACK_nX: /* LOCK Y TRACK -X */
                                {
                                        /* Projection of Vector on the plane */
                                        project_v3_v3v3(vec2, vec, cob->matrix[1]);
                                        sub_v3_v3v3(totmat[0], vec, vec2);
                                        normalize_v3(totmat[0]);
                                        negate_v3(totmat[0]);
                                        
                                        /* the y axis is fixed */
                                        normalize_v3_v3(totmat[1], cob->matrix[1]);
                                        
                                        /* the z axis gets mapped onto a third orthogonal vector */
                                        cross_v3_v3v3(totmat[2], totmat[0], totmat[1]);
                                }
                                        break;
                                case TRACK_nZ: /* LOCK Y TRACK -Z */
                                {
                                        /* Projection of Vector on the plane */
                                        project_v3_v3v3(vec2, vec, cob->matrix[1]);
                                        sub_v3_v3v3(totmat[2], vec, vec2);
                                        normalize_v3(totmat[2]);
                                        negate_v3(totmat[2]);
                                        
                                        /* the y axis is fixed */
                                        normalize_v3_v3(totmat[1], cob->matrix[1]);
                                        
                                        /* the z axis gets mapped onto a third orthogonal vector */
                                        cross_v3_v3v3(totmat[0], totmat[1], totmat[2]);
                                }
                                        break;
                                default:
                                {
                                        unit_m3(totmat);
                                }
                                        break;
                        }
                }
                        break;
                case LOCK_Z: /* LOCK Z */
                {
                        switch (data->trackflag) {
                                case TRACK_X: /* LOCK Z TRACK X */
                                {
                                        /* Projection of Vector on the plane */
                                        project_v3_v3v3(vec2, vec, cob->matrix[2]);
                                        sub_v3_v3v3(totmat[0], vec, vec2);
                                        normalize_v3(totmat[0]);
                                        
                                        /* the z axis is fixed */
                                        normalize_v3_v3(totmat[2], cob->matrix[2]);
                                        
                                        /* the x axis gets mapped onto a third orthogonal vector */
                                        cross_v3_v3v3(totmat[1], totmat[2], totmat[0]);
                                }
                                        break;
                                case TRACK_Y: /* LOCK Z TRACK Y */
                                {
                                        /* Projection of Vector on the plane */
                                        project_v3_v3v3(vec2, vec, cob->matrix[2]);
                                        sub_v3_v3v3(totmat[1], vec, vec2);
                                        normalize_v3(totmat[1]);
                                        
                                        /* the z axis is fixed */
                                        normalize_v3_v3(totmat[2], cob->matrix[2]);
                                                
                                        /* the x axis gets mapped onto a third orthogonal vector */
                                        cross_v3_v3v3(totmat[0], totmat[1], totmat[2]);
                                }
                                        break;
                                case TRACK_nX: /* LOCK Z TRACK -X */
                                {
                                        /* Projection of Vector on the plane */
                                        project_v3_v3v3(vec2, vec, cob->matrix[2]);
                                        sub_v3_v3v3(totmat[0], vec, vec2);
                                        normalize_v3(totmat[0]);
                                        negate_v3(totmat[0]);
                                        
                                        /* the z axis is fixed */
                                        normalize_v3_v3(totmat[2], cob->matrix[2]);
                                        
                                        /* the x axis gets mapped onto a third orthogonal vector */
                                        cross_v3_v3v3(totmat[1], totmat[2], totmat[0]);
                                }
                                        break;
                                case TRACK_nY: /* LOCK Z TRACK -Y */
                                {
                                        /* Projection of Vector on the plane */
                                        project_v3_v3v3(vec2, vec, cob->matrix[2]);
                                        sub_v3_v3v3(totmat[1], vec, vec2);
                                        normalize_v3(totmat[1]);
                                        negate_v3(totmat[1]);
                                        
                                        /* the z axis is fixed */
                                        normalize_v3_v3(totmat[2], cob->matrix[2]);
                                                
                                        /* the x axis gets mapped onto a third orthogonal vector */
                                        cross_v3_v3v3(totmat[0], totmat[1], totmat[2]);
                                }
                                        break;
                                default:
                                {
                                        unit_m3(totmat);
                                }
                                        break;
                        }
                }
                        break;
                default:
                {
                        unit_m3(totmat);
                }
                        break;
                }
                /* Block to keep matrix heading */
                copy_m3_m4(tmpmat, cob->matrix);
                normalize_m3(tmpmat);
                invert_m3_m3(invmat, tmpmat);
                mul_m3_m3m3(tmpmat, totmat, invmat);
                totmat[0][0] = tmpmat[0][0];totmat[0][1] = tmpmat[0][1];totmat[0][2] = tmpmat[0][2];
                totmat[1][0] = tmpmat[1][0];totmat[1][1] = tmpmat[1][1];totmat[1][2] = tmpmat[1][2];
                totmat[2][0] = tmpmat[2][0];totmat[2][1] = tmpmat[2][1];totmat[2][2] = tmpmat[2][2];
                
                copy_m4_m4(tmat, cob->matrix);
                
                mdet = determinant_m3(  totmat[0][0],totmat[0][1],totmat[0][2],
                                                totmat[1][0],totmat[1][1],totmat[1][2],
                                                totmat[2][0],totmat[2][1],totmat[2][2]);
                if (mdet==0) {
                        unit_m3(totmat);
                }
                
                /* apply out transformaton to the object */
                mul_m4_m3m4(cob->matrix, totmat, tmat);
        }
}

static bConstraintTypeInfo CTI_LOCKTRACK = {
        CONSTRAINT_TYPE_LOCKTRACK, /* type */
        sizeof(bLockTrackConstraint), /* size */
        "Locked Track", /* name */
        "bLockTrackConstraint", /* struct name */
        NULL, /* free data */
        NULL, /* relink data */
        locktrack_id_looper, /* id looper */
        NULL, /* copy data */
        locktrack_new_data, /* new data */
        locktrack_get_tars, /* get constraint targets */
        locktrack_flush_tars, /* flush constraint targets */
        default_get_tarmat, /* get target matrix */
        locktrack_evaluate /* evaluate */
};

/* ---------- Limit Distance Constraint ----------- */

static void distlimit_new_data (void *cdata)
{
        bDistLimitConstraint *data= (bDistLimitConstraint *)cdata;
        
        data->dist= 0.0f;
}

static void distlimit_id_looper (bConstraint *con, ConstraintIDFunc func, void *userdata)
{
        bDistLimitConstraint *data= con->data;
        
        /* target only */
        func(con, (ID**)&data->tar, userdata);
}

static int distlimit_get_tars (bConstraint *con, ListBase *list)
{
        if (con && list) {
                bDistLimitConstraint *data= con->data;
                bConstraintTarget *ct;
                
                /* standard target-getting macro for single-target constraints */
                SINGLETARGET_GET_TARS(con, data->tar, data->subtarget, ct, list)
                
                return 1;
        }
        
        return 0;
}

static void distlimit_flush_tars (bConstraint *con, ListBase *list, short nocopy)
{
        if (con && list) {
                bDistLimitConstraint *data= con->data;
                bConstraintTarget *ct= list->first;
                
                /* the following macro is used for all standard single-target constraints */
                SINGLETARGET_FLUSH_TARS(con, data->tar, data->subtarget, ct, list, nocopy)
        }
}

static void distlimit_evaluate (bConstraint *con, bConstraintOb *cob, ListBase *targets)
{
        bDistLimitConstraint *data= con->data;
        bConstraintTarget *ct= targets->first;
        
        /* only evaluate if there is a target */
        if (VALID_CONS_TARGET(ct)) {
                float dvec[3], dist=0.0f, sfac=1.0f;
                short clamp_surf= 0;
                
                /* calculate our current distance from the target */
                dist= len_v3v3(cob->matrix[3], ct->matrix[3]);
                
                /* set distance (flag is only set when user demands it) */
                if (data->dist == 0)
                        data->dist= dist;
                
                /* check if we're which way to clamp from, and calculate interpolation factor (if needed) */
                if (data->mode == LIMITDIST_OUTSIDE) {
                        /* if inside, then move to surface */
                        if (dist <= data->dist) {
                                clamp_surf= 1;
                                sfac= data->dist / dist;
                        }
                        /* if soft-distance is enabled, start fading once owner is dist+softdist from the target */
                        else if (data->flag & LIMITDIST_USESOFT) {
                                if (dist <= (data->dist + data->soft)) {
                                        
                                }
                        }
                }
                else if (data->mode == LIMITDIST_INSIDE) {
                        /* if outside, then move to surface */
                        if (dist >= data->dist) {
                                clamp_surf= 1;
                                sfac= data->dist / dist;
                        }
                        /* if soft-distance is enabled, start fading once owner is dist-soft from the target */
                        else if (data->flag & LIMITDIST_USESOFT) {
                                // FIXME: there's a problem with "jumping" when this kicks in
                                if (dist >= (data->dist - data->soft)) {
                                        sfac = (float)( data->soft*(1.0f - expf(-(dist - data->dist)/data->soft)) + data->dist );
                                        sfac /= dist;
                                        
                                        clamp_surf= 1;
                                }
                        }
                }
                else {
                        if (IS_EQF(dist, data->dist)==0) {
                                clamp_surf= 1;
                                sfac= data->dist / dist;
                        }
                }
                
                /* clamp to 'surface' (i.e. move owner so that dist == data->dist) */
                if (clamp_surf) {
                        /* simply interpolate along line formed by target -> owner */
                        interp_v3_v3v3(dvec, ct->matrix[3], cob->matrix[3], sfac);
                        
                        /* copy new vector onto owner */
                        copy_v3_v3(cob->matrix[3], dvec);
                }
        }
}

static bConstraintTypeInfo CTI_DISTLIMIT = {
        CONSTRAINT_TYPE_DISTLIMIT, /* type */
        sizeof(bDistLimitConstraint), /* size */
        "Limit Distance", /* name */
        "bDistLimitConstraint", /* struct name */
        NULL, /* free data */
        NULL, /* relink data */
        distlimit_id_looper, /* id looper */
        NULL, /* copy data */
        distlimit_new_data, /* new data */
        distlimit_get_tars, /* get constraint targets */
        distlimit_flush_tars, /* flush constraint targets */
        default_get_tarmat, /* get a target matrix */
        distlimit_evaluate /* evaluate */
};

/* ---------- Stretch To ------------ */

static void stretchto_new_data (void *cdata)
{
        bStretchToConstraint *data= (bStretchToConstraint *)cdata;
        
        data->volmode = 0;
        data->plane = 0;
        data->orglength = 0.0; 
        data->bulge = 1.0;
}

static void stretchto_id_looper (bConstraint *con, ConstraintIDFunc func, void *userdata)
{
        bStretchToConstraint *data= con->data;
        
        /* target only */
        func(con, (ID**)&data->tar, userdata);
}

static int stretchto_get_tars (bConstraint *con, ListBase *list)
{
        if (con && list) {
                bStretchToConstraint *data= con->data;
                bConstraintTarget *ct;
                
                /* standard target-getting macro for single-target constraints */
                SINGLETARGET_GET_TARS(con, data->tar, data->subtarget, ct, list)
                
                return 1;
        }
        
        return 0;
}

static void stretchto_flush_tars (bConstraint *con, ListBase *list, short nocopy)
{
        if (con && list) {
                bStretchToConstraint *data= con->data;
                bConstraintTarget *ct= list->first;
                
                /* the following macro is used for all standard single-target constraints */
                SINGLETARGET_FLUSH_TARS(con, data->tar, data->subtarget, ct, list, nocopy)
        }
}

static void stretchto_evaluate (bConstraint *con, bConstraintOb *cob, ListBase *targets)
{
        bStretchToConstraint *data= con->data;
        bConstraintTarget *ct= targets->first;
        
        /* only evaluate if there is a target */
        if (VALID_CONS_TARGET(ct)) {
                float size[3], scale[3], vec[3], xx[3], zz[3], orth[3];
                float totmat[3][3];
                float tmat[4][4];
                float dist;
                
                /* store scaling before destroying obmat */
                mat4_to_size(size, cob->matrix);
                
                /* store X orientation before destroying obmat */
                normalize_v3_v3(xx, cob->matrix[0]);
                
                /* store Z orientation before destroying obmat */
                normalize_v3_v3(zz, cob->matrix[2]);
                
                sub_v3_v3v3(vec, cob->matrix[3], ct->matrix[3]);
                vec[0] /= size[0];
                vec[1] /= size[1];
                vec[2] /= size[2];
                
                dist = normalize_v3(vec);
                //dist = len_v3v3( ob->obmat[3], targetmat[3]);
                
                /* data->orglength==0 occurs on first run, and after 'R' button is clicked */
                if (data->orglength == 0)  
                        data->orglength = dist;
                if (data->bulge == 0) 
                        data->bulge = 1.0;
                
                scale[1] = dist/data->orglength;
                switch (data->volmode) {
                /* volume preserving scaling */
                case VOLUME_XZ :
                        scale[0] = 1.0f - (float)sqrt(data->bulge) + (float)sqrt(data->bulge*(data->orglength/dist));
                        scale[2] = scale[0];
                        break;
                case VOLUME_X:
                        scale[0] = 1.0f + data->bulge * (data->orglength /dist - 1);
                        scale[2] = 1.0;
                        break;
                case VOLUME_Z:
                        scale[0] = 1.0;
                        scale[2] = 1.0f + data->bulge * (data->orglength /dist - 1);
                        break;
                        /* don't care for volume */
                case NO_VOLUME:
                        scale[0] = 1.0;
                        scale[2] = 1.0;
                        break;
                default: /* should not happen, but in case*/
                        return;    
                } /* switch (data->volmode) */

                /* Clear the object's rotation and scale */
                cob->matrix[0][0]=size[0]*scale[0];
                cob->matrix[0][1]=0;
                cob->matrix[0][2]=0;
                cob->matrix[1][0]=0;
                cob->matrix[1][1]=size[1]*scale[1];
                cob->matrix[1][2]=0;
                cob->matrix[2][0]=0;
                cob->matrix[2][1]=0;
                cob->matrix[2][2]=size[2]*scale[2];
                
                sub_v3_v3v3(vec, cob->matrix[3], ct->matrix[3]);
                normalize_v3(vec);
                
                /* new Y aligns  object target connection*/
                negate_v3_v3(totmat[1], vec);
                switch (data->plane) {
                case PLANE_X:
                        /* build new Z vector */
                        /* othogonal to "new Y" "old X! plane */
                        cross_v3_v3v3(orth, vec, xx);
                        normalize_v3(orth);
                        
                        /* new Z*/
                        copy_v3_v3(totmat[2], orth);
                        
                        /* we decided to keep X plane*/
                        cross_v3_v3v3(xx, orth, vec);
                        normalize_v3_v3(totmat[0], xx);
                        break;
                case PLANE_Z:
                        /* build new X vector */
                        /* othogonal to "new Y" "old Z! plane */
                        cross_v3_v3v3(orth, vec, zz);
                        normalize_v3(orth);
                        
                        /* new X */
                        negate_v3_v3(totmat[0], orth);
                        
                        /* we decided to keep Z */
                        cross_v3_v3v3(zz, orth, vec);
                        normalize_v3_v3(totmat[2], zz);
                        break;
                } /* switch (data->plane) */
                
                copy_m4_m4(tmat, cob->matrix);
                mul_m4_m3m4(cob->matrix, totmat, tmat);
        }
}

static bConstraintTypeInfo CTI_STRETCHTO = {
        CONSTRAINT_TYPE_STRETCHTO, /* type */
        sizeof(bStretchToConstraint), /* size */
        "Stretch To", /* name */
        "bStretchToConstraint", /* struct name */
        NULL, /* free data */
        NULL, /* relink data */
        stretchto_id_looper, /* id looper */
        NULL, /* copy data */
        stretchto_new_data, /* new data */
        stretchto_get_tars, /* get constraint targets */
        stretchto_flush_tars, /* flush constraint targets */
        default_get_tarmat, /* get target matrix */
        stretchto_evaluate /* evaluate */
};

/* ---------- Floor ------------ */

static void minmax_new_data (void *cdata)
{
        bMinMaxConstraint *data= (bMinMaxConstraint *)cdata;
        
        data->minmaxflag = TRACK_Z;
        data->offset = 0.0f;
        data->cache[0] = data->cache[1] = data->cache[2] = 0.0f;
        data->flag = 0;
}

static void minmax_id_looper (bConstraint *con, ConstraintIDFunc func, void *userdata)
{
        bMinMaxConstraint *data= con->data;
        
        /* target only */
        func(con, (ID**)&data->tar, userdata);
}

static int minmax_get_tars (bConstraint *con, ListBase *list)
{
        if (con && list) {
                bMinMaxConstraint *data= con->data;
                bConstraintTarget *ct;
                
                /* standard target-getting macro for single-target constraints */
                SINGLETARGET_GET_TARS(con, data->tar, data->subtarget, ct, list)
                
                return 1;
        }
        
        return 0;
}

static void minmax_flush_tars (bConstraint *con, ListBase *list, short nocopy)
{
        if (con && list) {
                bMinMaxConstraint *data= con->data;
                bConstraintTarget *ct= list->first;
                
                /* the following macro is used for all standard single-target constraints */
                SINGLETARGET_FLUSH_TARS(con, data->tar, data->subtarget, ct, list, nocopy)
        }
}

static void minmax_evaluate (bConstraint *con, bConstraintOb *cob, ListBase *targets)
{
        bMinMaxConstraint *data= con->data;
        bConstraintTarget *ct= targets->first;
        
        /* only evaluate if there is a target */
        if (VALID_CONS_TARGET(ct)) {
                float obmat[4][4], imat[4][4], tarmat[4][4], tmat[4][4];
                float val1, val2;
                int index;
                
                copy_m4_m4(obmat, cob->matrix);
                copy_m4_m4(tarmat, ct->matrix);
                
                if (data->flag & MINMAX_USEROT) {
                        /* take rotation of target into account by doing the transaction in target's localspace */
                        invert_m4_m4(imat, tarmat);
                        mul_m4_m4m4(tmat, obmat, imat);
                        copy_m4_m4(obmat, tmat);
                        unit_m4(tarmat);
                }
                
                switch (data->minmaxflag) {
                case TRACK_Z:
                        val1 = tarmat[3][2];
                        val2 = obmat[3][2]-data->offset;
                        index = 2;
                        break;
                case TRACK_Y:
                        val1 = tarmat[3][1];
                        val2 = obmat[3][1]-data->offset;
                        index = 1;
                        break;
                case TRACK_X:
                        val1 = tarmat[3][0];
                        val2 = obmat[3][0]-data->offset;
                        index = 0;
                        break;
                case TRACK_nZ:
                        val2 = tarmat[3][2];
                        val1 = obmat[3][2]-data->offset;
                        index = 2;
                        break;
                case TRACK_nY:
                        val2 = tarmat[3][1];
                        val1 = obmat[3][1]-data->offset;
                        index = 1;
                        break;
                case TRACK_nX:
                        val2 = tarmat[3][0];
                        val1 = obmat[3][0]-data->offset;
                        index = 0;
                        break;
                default:
                        return;
                }
                
                if (val1 > val2) {
                        obmat[3][index] = tarmat[3][index] + data->offset;
                        if (data->flag & MINMAX_STICKY) {
                                if (data->flag & MINMAX_STUCK) {
                                        copy_v3_v3(obmat[3], data->cache);
                                } 
                                else {
                                        copy_v3_v3(data->cache, obmat[3]);
                                        data->flag |= MINMAX_STUCK;
                                }
                        }
                        if (data->flag & MINMAX_USEROT) {
                                /* get out of localspace */
                                mul_m4_m4m4(tmat, obmat, ct->matrix);
                                copy_m4_m4(cob->matrix, tmat);
                        } 
                        else {                  
                                copy_v3_v3(cob->matrix[3], obmat[3]);
                        }
                } 
                else {
                        data->flag &= ~MINMAX_STUCK;
                }
        }
}

static bConstraintTypeInfo CTI_MINMAX = {
        CONSTRAINT_TYPE_MINMAX, /* type */
        sizeof(bMinMaxConstraint), /* size */
        "Floor", /* name */
        "bMinMaxConstraint", /* struct name */
        NULL, /* free data */
        NULL, /* relink data */
        minmax_id_looper, /* id looper */
        NULL, /* copy data */
        minmax_new_data, /* new data */
        minmax_get_tars, /* get constraint targets */
        minmax_flush_tars, /* flush constraint targets */
        default_get_tarmat, /* get target matrix */
        minmax_evaluate /* evaluate */
};

/* ------- RigidBody Joint ---------- */

static void rbj_new_data (void *cdata)
{
        bRigidBodyJointConstraint *data= (bRigidBodyJointConstraint *)cdata;
        
        // removed code which set target of this constraint  
        data->type=1;
}

static void rbj_id_looper (bConstraint *con, ConstraintIDFunc func, void *userdata)
{
        bRigidBodyJointConstraint *data= con->data;
        
        /* target only */
        func(con, (ID**)&data->tar, userdata);
        func(con, (ID**)&data->child, userdata);
}

static int rbj_get_tars (bConstraint *con, ListBase *list)
{
        if (con && list) {
                bRigidBodyJointConstraint *data= con->data;
                bConstraintTarget *ct;
                
                /* standard target-getting macro for single-target constraints without subtargets */
                SINGLETARGETNS_GET_TARS(con, data->tar, ct, list)
                
                return 1;
        }
        
        return 0;
}

static void rbj_flush_tars (bConstraint *con, ListBase *list, short nocopy)
{
        if (con && list) {
                bRigidBodyJointConstraint *data= con->data;
                bConstraintTarget *ct= list->first;
                
                /* the following macro is used for all standard single-target constraints */
                SINGLETARGETNS_FLUSH_TARS(con, data->tar, ct, list, nocopy)
        }
}

static bConstraintTypeInfo CTI_RIGIDBODYJOINT = {
        CONSTRAINT_TYPE_RIGIDBODYJOINT, /* type */
        sizeof(bRigidBodyJointConstraint), /* size */
        "Rigid Body Joint", /* name */
        "bRigidBodyJointConstraint", /* struct name */
        NULL, /* free data */
        NULL, /* relink data */
        rbj_id_looper, /* id looper */
        NULL, /* copy data */
        rbj_new_data, /* new data */
        rbj_get_tars, /* get constraint targets */
        rbj_flush_tars, /* flush constraint targets */
        default_get_tarmat, /* get target matrix */
        NULL /* evaluate - this is not solved here... is just an interface for game-engine */
};

/* -------- Clamp To ---------- */

static void clampto_id_looper (bConstraint *con, ConstraintIDFunc func, void *userdata)
{
        bClampToConstraint *data= con->data;
        
        /* target only */
        func(con, (ID**)&data->tar, userdata);
}

static int clampto_get_tars (bConstraint *con, ListBase *list)
{
        if (con && list) {
                bClampToConstraint *data= con->data;
                bConstraintTarget *ct;
                
                /* standard target-getting macro for single-target constraints without subtargets */
                SINGLETARGETNS_GET_TARS(con, data->tar, ct, list)
                
                return 1;
        }
        
        return 0;
}

static void clampto_flush_tars (bConstraint *con, ListBase *list, short nocopy)
{
        if (con && list) {
                bClampToConstraint *data= con->data;
                bConstraintTarget *ct= list->first;
                
                /* the following macro is used for all standard single-target constraints */
                SINGLETARGETNS_FLUSH_TARS(con, data->tar, ct, list, nocopy)
        }
}

static void clampto_get_tarmat (bConstraint *UNUSED(con), bConstraintOb *cob, bConstraintTarget *ct, float UNUSED(ctime))
{
        if (VALID_CONS_TARGET(ct)) {
                Curve *cu= ct->tar->data;
                
                /* note: when creating constraints that follow path, the curve gets the CU_PATH set now,
                 *              currently for paths to work it needs to go through the bevlist/displist system (ton) 
                 */
                
                /* only happens on reload file, but violates depsgraph still... fix! */
                if (cu->path==NULL || cu->path->data==NULL)
                        makeDispListCurveTypes(cob->scene, ct->tar, 0);
        }
        
        /* technically, this isn't really needed for evaluation, but we don't know what else
         * might end up calling this...
         */
        if (ct)
                unit_m4(ct->matrix);
}

static void clampto_evaluate (bConstraint *con, bConstraintOb *cob, ListBase *targets)
{
        bClampToConstraint *data= con->data;
        bConstraintTarget *ct= targets->first;
        
        /* only evaluate if there is a target and it is a curve */
        if (VALID_CONS_TARGET(ct) && (ct->tar->type == OB_CURVE)) {
                Curve *cu= data->tar->data;
                float obmat[4][4], ownLoc[3];
                float curveMin[3], curveMax[3];
                float targetMatrix[4][4]= MAT4_UNITY;
                
                copy_m4_m4(obmat, cob->matrix);
                copy_v3_v3(ownLoc, obmat[3]);
                
                INIT_MINMAX(curveMin, curveMax)
                minmax_object(ct->tar, curveMin, curveMax);
                
                /* get targetmatrix */
                if (cu->path && cu->path->data) {
                        float vec[4], dir[3], totmat[4][4];
                        float curvetime;
                        short clamp_axis;
                        
                        /* find best position on curve */
                        /* 1. determine which axis to sample on? */
                        if (data->flag == CLAMPTO_AUTO) {
                                float size[3];
                                sub_v3_v3v3(size, curveMax, curveMin);
                                
                                /* find axis along which the bounding box has the greatest
                                 * extent. Otherwise, default to the x-axis, as that is quite
                                 * frequently used.
                                 */
                                if ((size[2]>size[0]) && (size[2]>size[1]))
                                        clamp_axis= CLAMPTO_Z - 1;
                                else if ((size[1]>size[0]) && (size[1]>size[2]))
                                        clamp_axis= CLAMPTO_Y - 1;
                                else
                                        clamp_axis = CLAMPTO_X - 1;
                        }
                        else 
                                clamp_axis= data->flag - 1;
                                
                        /* 2. determine position relative to curve on a 0-1 scale based on bounding box */
                        if (data->flag2 & CLAMPTO_CYCLIC) {
                                /* cyclic, so offset within relative bounding box is used */
                                float len= (curveMax[clamp_axis] - curveMin[clamp_axis]);
                                float offset;
                                
                                /* check to make sure len is not so close to zero that it'll cause errors */
                                if (IS_EQ(len, 0) == 0) {
                                        /* find bounding-box range where target is located */
                                        if (ownLoc[clamp_axis] < curveMin[clamp_axis]) {
                                                /* bounding-box range is before */
                                                offset= curveMin[clamp_axis];
                                                
                                                while (ownLoc[clamp_axis] < offset)
                                                        offset -= len;
                                                
                                                /* now, we calculate as per normal, except using offset instead of curveMin[clamp_axis] */
                                                curvetime = (ownLoc[clamp_axis] - offset) / (len);
                                        }
                                        else if (ownLoc[clamp_axis] > curveMax[clamp_axis]) {
                                                /* bounding-box range is after */
                                                offset= curveMax[clamp_axis];
                                                
                                                while (ownLoc[clamp_axis] > offset) {
                                                        if ((offset + len) > ownLoc[clamp_axis])
                                                                break;
                                                        else
                                                                offset += len;
                                                }
                                                
                                                /* now, we calculate as per normal, except using offset instead of curveMax[clamp_axis] */
                                                curvetime = (ownLoc[clamp_axis] - offset) / (len);
                                        }
                                        else {
                                                /* as the location falls within bounds, just calculate */
                                                curvetime = (ownLoc[clamp_axis] - curveMin[clamp_axis]) / (len);
                                        }
                                }
                                else {
                                        /* as length is close to zero, curvetime by default should be 0 (i.e. the start) */
                                        curvetime= 0.0f;
                                }
                        }
                        else {
                                /* no cyclic, so position is clamped to within the bounding box */
                                if (ownLoc[clamp_axis] <= curveMin[clamp_axis])
                                        curvetime = 0.0f;
                                else if (ownLoc[clamp_axis] >= curveMax[clamp_axis])
                                        curvetime = 1.0f;
                                else if ( IS_EQ((curveMax[clamp_axis] - curveMin[clamp_axis]), 0) == 0 )
                                        curvetime = (ownLoc[clamp_axis] - curveMin[clamp_axis]) / (curveMax[clamp_axis] - curveMin[clamp_axis]);
                                else 
                                        curvetime = 0.0f;
                        }
                        
                        /* 3. position on curve */
                        if (where_on_path(ct->tar, curvetime, vec, dir, NULL, NULL, NULL) ) {
                                unit_m4(totmat);
                                copy_v3_v3(totmat[3], vec);
                                
                                mul_serie_m4(targetMatrix, ct->tar->obmat, totmat, NULL, NULL, NULL, NULL, NULL, NULL);
                        }
                }
                
                /* obtain final object position */
                copy_v3_v3(cob->matrix[3], targetMatrix[3]);
        }
}

static bConstraintTypeInfo CTI_CLAMPTO = {
        CONSTRAINT_TYPE_CLAMPTO, /* type */
        sizeof(bClampToConstraint), /* size */
        "Clamp To", /* name */
        "bClampToConstraint", /* struct name */
        NULL, /* free data */
        NULL, /* relink data */
        clampto_id_looper, /* id looper */
        NULL, /* copy data */
        NULL, /* new data */
        clampto_get_tars, /* get constraint targets */
        clampto_flush_tars, /* flush constraint targets */
        clampto_get_tarmat, /* get target matrix */
        clampto_evaluate /* evaluate */
};

/* ---------- Transform Constraint ----------- */

static void transform_new_data (void *cdata)
{
        bTransformConstraint *data= (bTransformConstraint *)cdata;
        
        data->map[0]= 0;
        data->map[1]= 1;
        data->map[2]= 2;
}

static void transform_id_looper (bConstraint *con, ConstraintIDFunc func, void *userdata)
{
        bTransformConstraint *data= con->data;
        
        /* target only */
        func(con, (ID**)&data->tar, userdata);
}

static int transform_get_tars (bConstraint *con, ListBase *list)
{
        if (con && list) {
                bTransformConstraint *data= con->data;
                bConstraintTarget *ct;
                
                /* standard target-getting macro for single-target constraints */
                SINGLETARGET_GET_TARS(con, data->tar, data->subtarget, ct, list)
                
                return 1;
        }
        
        return 0;
}

static void transform_flush_tars (bConstraint *con, ListBase *list, short nocopy)
{
        if (con && list) {
                bTransformConstraint *data= con->data;
                bConstraintTarget *ct= list->first;
                
                /* the following macro is used for all standard single-target constraints */
                SINGLETARGET_FLUSH_TARS(con, data->tar, data->subtarget, ct, list, nocopy)
        }
}

static void transform_evaluate (bConstraint *con, bConstraintOb *cob, ListBase *targets)
{
        bTransformConstraint *data= con->data;
        bConstraintTarget *ct= targets->first;
        
        /* only evaluate if there is a target */
        if (VALID_CONS_TARGET(ct)) {
                float loc[3], eul[3], size[3];
                float dvec[3], sval[3];
                int i;
                
                /* obtain target effect */
                switch (data->from) {
                        case 2: /* scale */
                                mat4_to_size( dvec,ct->matrix);
                                break;
                        case 1: /* rotation (convert to degrees first) */
                                mat4_to_eulO(dvec, cob->rotOrder, ct->matrix);
                                mul_v3_fl(dvec, (float)(180.0/M_PI)); /* rad -> deg */
                                break;
                        default: /* location */
                                copy_v3_v3(dvec, ct->matrix[3]);
                                break;
                }
                
                /* extract components of owner's matrix */
                copy_v3_v3(loc, cob->matrix[3]);
                mat4_to_eulO(eul, cob->rotOrder, cob->matrix);
                mat4_to_size(size, cob->matrix);        
                
                /* determine where in range current transforms lie */
                if (data->expo) {
                        for (i=0; i<3; i++) {
                                if (data->from_max[i] - data->from_min[i])
                                        sval[i]= (dvec[i] - data->from_min[i]) / (data->from_max[i] - data->from_min[i]);
                                else
                                        sval[i]= 0.0f;
                        }
                }
                else {
                        /* clamp transforms out of range */
                        for (i=0; i<3; i++) {
                                CLAMP(dvec[i], data->from_min[i], data->from_max[i]);
                                if (data->from_max[i] - data->from_min[i])
                                        sval[i]= (dvec[i] - data->from_min[i]) / (data->from_max[i] - data->from_min[i]);
                                else
                                        sval[i]= 0.0f;
                        }
                }
                
                
                /* apply transforms */
                switch (data->to) {
                        case 2: /* scaling */
                                for (i=0; i<3; i++)
                                        size[i]= data->to_min[i] + (sval[(int)data->map[i]] * (data->to_max[i] - data->to_min[i])); 
                                break;
                        case 1: /* rotation */
                                for (i=0; i<3; i++) {
                                        float tmin, tmax;
                                        
                                        tmin= data->to_min[i];
                                        tmax= data->to_max[i];
                                        
                                        /* all values here should be in degrees */
                                        eul[i]= tmin + (sval[(int)data->map[i]] * (tmax - tmin)); 
                                        
                                        /* now convert final value back to radians */
                                        eul[i] = DEG2RADF(eul[i]);
                                }
                                break;
                        default: /* location */
                                /* get new location */
                                for (i=0; i<3; i++)
                                        loc[i]= (data->to_min[i] + (sval[(int)data->map[i]] * (data->to_max[i] - data->to_min[i])));
                                
                                /* add original location back on (so that it can still be moved) */
                                add_v3_v3v3(loc, cob->matrix[3], loc);
                                break;
                }
                
                /* apply to matrix */
                loc_eulO_size_to_mat4(cob->matrix, loc, eul, size, cob->rotOrder);
        }
}

static bConstraintTypeInfo CTI_TRANSFORM = {
        CONSTRAINT_TYPE_TRANSFORM, /* type */
        sizeof(bTransformConstraint), /* size */
        "Transform", /* name */
        "bTransformConstraint", /* struct name */
        NULL, /* free data */
        NULL, /* relink data */
        transform_id_looper, /* id looper */
        NULL, /* copy data */
        transform_new_data, /* new data */
        transform_get_tars, /* get constraint targets */
        transform_flush_tars, /* flush constraint targets */
        default_get_tarmat, /* get a target matrix */
        transform_evaluate /* evaluate */
};

/* ---------- Shrinkwrap Constraint ----------- */

static void shrinkwrap_id_looper (bConstraint *con, ConstraintIDFunc func, void *userdata)
{
        bShrinkwrapConstraint *data= con->data;
        
        /* target only */
        func(con, (ID**)&data->target, userdata);
}

static int shrinkwrap_get_tars (bConstraint *con, ListBase *list)
{
        if (con && list) {
                bShrinkwrapConstraint *data = con->data;
                bConstraintTarget *ct;
                
                SINGLETARGETNS_GET_TARS(con, data->target, ct, list)
                
                return 1;
        }
        
        return 0;
}


static void shrinkwrap_flush_tars (bConstraint *con, ListBase *list, short nocopy)
{
        if (con && list) {
                bShrinkwrapConstraint *data = con->data;
                bConstraintTarget *ct= list->first;
                
                SINGLETARGETNS_FLUSH_TARS(con, data->target, ct, list, nocopy)
        }
}


static void shrinkwrap_get_tarmat (bConstraint *con, bConstraintOb *cob, bConstraintTarget *ct, float UNUSED(ctime))
{
        bShrinkwrapConstraint *scon = (bShrinkwrapConstraint *) con->data;
        
        if( VALID_CONS_TARGET(ct) && (ct->tar->type == OB_MESH) )
        {
                int fail = FALSE;
                float co[3] = {0.0f, 0.0f, 0.0f};
                float no[3] = {0.0f, 0.0f, 0.0f};
                float dist;
                
                SpaceTransform transform;
                DerivedMesh *target = object_get_derived_final(ct->tar);
                BVHTreeRayHit hit;
                BVHTreeNearest nearest;
                
                BVHTreeFromMesh treeData= {NULL};
                
                nearest.index = -1;
                nearest.dist = FLT_MAX;
                
                hit.index = -1;
                hit.dist = 100000.0f;  //TODO should use FLT_MAX.. but normal projection doenst yet supports it
                
                unit_m4(ct->matrix);
                
                if(target != NULL)
                {
                        space_transform_from_matrixs(&transform, cob->matrix, ct->tar->obmat);
                        
                        switch(scon->shrinkType)
                        {
                                case MOD_SHRINKWRAP_NEAREST_SURFACE:
                                case MOD_SHRINKWRAP_NEAREST_VERTEX:
                                        
                                        if(scon->shrinkType == MOD_SHRINKWRAP_NEAREST_VERTEX)
                                                bvhtree_from_mesh_verts(&treeData, target, 0.0, 2, 6);
                                        else
                                                bvhtree_from_mesh_faces(&treeData, target, 0.0, 2, 6);
                                        
                                        if(treeData.tree == NULL)
                                        {
                                                fail = TRUE;
                                                break;
                                        }
                                        
                                        space_transform_apply(&transform, co);
                                        
                                        BLI_bvhtree_find_nearest(treeData.tree, co, &nearest, treeData.nearest_callback, &treeData);
                                        
                                        dist = len_v3v3(co, nearest.co);
                                        if(dist != 0.0f) {
                                                interp_v3_v3v3(co, co, nearest.co, (dist - scon->dist)/dist);   /* linear interpolation */
                                        }
                                        space_transform_invert(&transform, co);
                                break;
                                
                                case MOD_SHRINKWRAP_PROJECT:
                                        if(scon->projAxis & MOD_SHRINKWRAP_PROJECT_OVER_X_AXIS) no[0] = 1.0f;
                                        if(scon->projAxis & MOD_SHRINKWRAP_PROJECT_OVER_Y_AXIS) no[1] = 1.0f;
                                        if(scon->projAxis & MOD_SHRINKWRAP_PROJECT_OVER_Z_AXIS) no[2] = 1.0f;
                                        
                                        if(INPR(no,no) < FLT_EPSILON)
                                        {
                                                fail = TRUE;
                                                break;
                                        }
                                        
                                        normalize_v3(no);
                                        
                                        
                                        bvhtree_from_mesh_faces(&treeData, target, scon->dist, 4, 6);
                                        if(treeData.tree == NULL)
                                        {
                                                fail = TRUE;
                                                break;
                                        }
                                        
                                        if(normal_projection_project_vertex(0, co, no, &transform, treeData.tree, &hit, treeData.raycast_callback, &treeData) == FALSE)
                                        {
                                                fail = TRUE;
                                                break;
                                        }
                                        copy_v3_v3(co, hit.co);
                                break;
                        }
                        
                        free_bvhtree_from_mesh(&treeData);
                        
                        target->release(target);
                        
                        if(fail == TRUE)
                        {
                                /* Don't move the point */
                                co[0] = co[1] = co[2] = 0.0f;
                        }
                        
                        /* co is in local object coordinates, change it to global and update target position */
                        mul_m4_v3(cob->matrix, co);
                        copy_v3_v3(ct->matrix[3], co);
                }
        }
}

static void shrinkwrap_evaluate (bConstraint *UNUSED(con), bConstraintOb *cob, ListBase *targets)
{
        bConstraintTarget *ct= targets->first;
        
        /* only evaluate if there is a target */
        if (VALID_CONS_TARGET(ct))
        {
                copy_v3_v3(cob->matrix[3], ct->matrix[3]);
        }
}

static bConstraintTypeInfo CTI_SHRINKWRAP = {
        CONSTRAINT_TYPE_SHRINKWRAP, /* type */
        sizeof(bShrinkwrapConstraint), /* size */
        "Shrinkwrap", /* name */
        "bShrinkwrapConstraint", /* struct name */
        NULL, /* free data */
        NULL, /* relink data */
        shrinkwrap_id_looper, /* id looper */
        NULL, /* copy data */
        NULL, /* new data */
        shrinkwrap_get_tars, /* get constraint targets */
        shrinkwrap_flush_tars, /* flush constraint targets */
        shrinkwrap_get_tarmat, /* get a target matrix */
        shrinkwrap_evaluate /* evaluate */
};

/* --------- Damped Track ---------- */

static void damptrack_new_data (void *cdata)
{
        bDampTrackConstraint *data= (bDampTrackConstraint *)cdata;
        
        data->trackflag = TRACK_Y;
}       

static void damptrack_id_looper (bConstraint *con, ConstraintIDFunc func, void *userdata)
{
        bDampTrackConstraint *data= con->data;
        
        /* target only */
        func(con, (ID**)&data->tar, userdata);
}

static int damptrack_get_tars (bConstraint *con, ListBase *list)
{
        if (con && list) {
                bDampTrackConstraint *data= con->data;
                bConstraintTarget *ct;
                
                /* the following macro is used for all standard single-target constraints */
                SINGLETARGET_GET_TARS(con, data->tar, data->subtarget, ct, list)
                
                return 1;
        }
        
        return 0;
}

static void damptrack_flush_tars (bConstraint *con, ListBase *list, short nocopy)
{
        if (con && list) {
                bDampTrackConstraint *data= con->data;
                bConstraintTarget *ct= list->first;
                
                /* the following macro is used for all standard single-target constraints */
                SINGLETARGET_FLUSH_TARS(con, data->tar, data->subtarget, ct, list, nocopy)
        }
}

/* array of direction vectors for the tracking flags */
static const float track_dir_vecs[6][3] = {
        {+1,0,0}, {0,+1,0}, {0,0,+1},           /* TRACK_X,  TRACK_Y,  TRACK_Z */
        {-1,0,0}, {0,-1,0}, {0,0,-1}            /* TRACK_NX, TRACK_NY, TRACK_NZ */
};

static void damptrack_evaluate (bConstraint *con, bConstraintOb *cob, ListBase *targets)
{
        bDampTrackConstraint *data= con->data;
        bConstraintTarget *ct= targets->first;
        
        if (VALID_CONS_TARGET(ct)) {
                float obvec[3], tarvec[3], obloc[3];
                float raxis[3], rangle;
                float rmat[3][3], tmat[4][4];
                
                /* find the (unit) direction that the axis we're interested in currently points 
                 *      - mul_mat3_m4_v3() only takes the 3x3 (rotation+scaling) components of the 4x4 matrix 
                 *      - the normalisation step at the end should take care of any unwanted scaling
                 *        left over in the 3x3 matrix we used
                 */
                copy_v3_v3(obvec, track_dir_vecs[data->trackflag]);
                mul_mat3_m4_v3(cob->matrix, obvec);
                
                if (normalize_v3(obvec) == 0.0f) {
                        /* exceptional case - just use the track vector as appropriate */
                        copy_v3_v3(obvec, track_dir_vecs[data->trackflag]);
                }
                
                /* find the (unit) direction vector going from the owner to the target */
                copy_v3_v3(obloc, cob->matrix[3]);
                sub_v3_v3v3(tarvec, ct->matrix[3], obloc);
                
                if (normalize_v3(tarvec) == 0.0f) {
                        /* the target is sitting on the owner, so just make them use the same direction vectors */
                        // FIXME: or would it be better to use the pure direction vector?
                        copy_v3_v3(tarvec, obvec);
                        //copy_v3_v3(tarvec, track_dir_vecs[data->trackflag]);
                }
                
                /* determine the axis-angle rotation, which represents the smallest possible rotation
                 * between the two rotation vectors (i.e. the 'damping' referred to in the name)
                 *      - we take this to be the rotation around the normal axis/vector to the plane defined
                 *        by the current and destination vectors, which will 'map' the current axis to the 
                 *        destination vector
                 *      - the min/max wrappers around (obvec . tarvec) result (stored temporarily in rangle)
                 *        are used to ensure that the smallest angle is chosen
                 */
                cross_v3_v3v3(raxis, obvec, tarvec);
                
                rangle= dot_v3v3(obvec, tarvec);
                rangle= acos( MAX2(-1.0f, MIN2(1.0f, rangle)) );
                
                /* construct rotation matrix from the axis-angle rotation found above 
                 *      - this call takes care to make sure that the axis provided is a unit vector first
                 */
                axis_angle_to_mat3(rmat, raxis, rangle);
                
                /* rotate the owner in the way defined by this rotation matrix, then reapply the location since
                 * we may have destroyed that in the process of multiplying the matrix
                 */
                unit_m4(tmat);
                mul_m4_m3m4(tmat, rmat, cob->matrix); // m1, m3, m2
                
                copy_m4_m4(cob->matrix, tmat);
                copy_v3_v3(cob->matrix[3], obloc);
        }
}

static bConstraintTypeInfo CTI_DAMPTRACK = {
        CONSTRAINT_TYPE_DAMPTRACK, /* type */
        sizeof(bDampTrackConstraint), /* size */
        "Damped Track", /* name */
        "bDampTrackConstraint", /* struct name */
        NULL, /* free data */
        NULL, /* relink data */
        damptrack_id_looper, /* id looper */
        NULL, /* copy data */
        damptrack_new_data, /* new data */
        damptrack_get_tars, /* get constraint targets */
        damptrack_flush_tars, /* flush constraint targets */
        default_get_tarmat, /* get target matrix */
        damptrack_evaluate /* evaluate */
};

/* ----------- Spline IK ------------ */

static void splineik_free (bConstraint *con)
{
        bSplineIKConstraint *data= con->data;
        
        /* binding array */
        if (data->points)
                MEM_freeN(data->points);
}       

static void splineik_copy (bConstraint *con, bConstraint *srccon)
{
        bSplineIKConstraint *src= srccon->data;
        bSplineIKConstraint *dst= con->data;
        
        /* copy the binding array */
        dst->points= MEM_dupallocN(src->points);
}

static void splineik_new_data (void *cdata)
{
        bSplineIKConstraint *data= (bSplineIKConstraint *)cdata;

        data->chainlen= 1;
}

static void splineik_id_looper (bConstraint *con, ConstraintIDFunc func, void *userdata)
{
        bSplineIKConstraint *data= con->data;
        
        /* target only */
        func(con, (ID**)&data->tar, userdata);
}

static int splineik_get_tars (bConstraint *con, ListBase *list)
{
        if (con && list) {
                bSplineIKConstraint *data= con->data;
                bConstraintTarget *ct;
                
                /* standard target-getting macro for single-target constraints without subtargets */
                SINGLETARGETNS_GET_TARS(con, data->tar, ct, list)
                
                return 1;
        }
        
        return 0;
}

static void splineik_flush_tars (bConstraint *con, ListBase *list, short nocopy)
{
        if (con && list) {
                bSplineIKConstraint *data= con->data;
                bConstraintTarget *ct= list->first;
                
                /* the following macro is used for all standard single-target constraints */
                SINGLETARGETNS_FLUSH_TARS(con, data->tar, ct, list, nocopy)
        }
}

static void splineik_get_tarmat (bConstraint *UNUSED(con), bConstraintOb *cob, bConstraintTarget *ct, float UNUSED(ctime))
{
        if (VALID_CONS_TARGET(ct)) {
                Curve *cu= ct->tar->data;
                
                /* note: when creating constraints that follow path, the curve gets the CU_PATH set now,
                 *              currently for paths to work it needs to go through the bevlist/displist system (ton) 
                 */
                
                /* only happens on reload file, but violates depsgraph still... fix! */
                if (cu->path==NULL || cu->path->data==NULL)
                        makeDispListCurveTypes(cob->scene, ct->tar, 0);
        }
        
        /* technically, this isn't really needed for evaluation, but we don't know what else
         * might end up calling this...
         */
        if (ct)
                unit_m4(ct->matrix);
}

static bConstraintTypeInfo CTI_SPLINEIK = {
        CONSTRAINT_TYPE_SPLINEIK, /* type */
        sizeof(bSplineIKConstraint), /* size */
        "Spline IK", /* name */
        "bSplineIKConstraint", /* struct name */
        splineik_free, /* free data */
        NULL, /* relink data */
        splineik_id_looper, /* id looper */
        splineik_copy, /* copy data */
        splineik_new_data, /* new data */
        splineik_get_tars, /* get constraint targets */
        splineik_flush_tars, /* flush constraint targets */
        splineik_get_tarmat, /* get target matrix */
        NULL /* evaluate - solved as separate loop */
};

/* ----------- Pivot ------------- */

static void pivotcon_id_looper (bConstraint *con, ConstraintIDFunc func, void *userdata)
{
        bPivotConstraint *data= con->data;
        
        /* target only */
        func(con, (ID**)&data->tar, userdata);
}

static int pivotcon_get_tars (bConstraint *con, ListBase *list)
{
        if (con && list) {
                bPivotConstraint *data= con->data;
                bConstraintTarget *ct;
                
                /* standard target-getting macro for single-target constraints */
                SINGLETARGET_GET_TARS(con, data->tar, data->subtarget, ct, list)
                
                return 1;
        }
        
        return 0;
}

static void pivotcon_flush_tars (bConstraint *con, ListBase *list, short nocopy)
{
        if (con && list) {
                bPivotConstraint *data= con->data;
                bConstraintTarget *ct= list->first;
                
                /* the following macro is used for all standard single-target constraints */
                SINGLETARGET_FLUSH_TARS(con, data->tar, data->subtarget, ct, list, nocopy)
        }
}

static void pivotcon_evaluate (bConstraint *con, bConstraintOb *cob, ListBase *targets)
{
        bPivotConstraint *data= con->data;
        bConstraintTarget *ct= targets->first;
        
        float pivot[3], vec[3];
        float rotMat[3][3];

        /* pivot correction */
        float axis[3], angle;
        
        /* firstly, check if pivoting should take place based on the current rotation */
        if (data->rotAxis != PIVOTCON_AXIS_NONE) {
                float rot[3];
                
                /* extract euler-rotation of target */
                mat4_to_eulO(rot, cob->rotOrder, cob->matrix);
                
                /* check which range might be violated */
                if (data->rotAxis < PIVOTCON_AXIS_X) {
                        /* negative rotations (data->rotAxis = 0 -> 2) */
                        if (rot[data->rotAxis] > 0.0f)
                                return;
                }
                else {
                        /* positive rotations (data->rotAxis = 3 -> 5 */
                        if (rot[data->rotAxis - PIVOTCON_AXIS_X] < 0.0f)
                                return;
                }
        }
        
        /* find the pivot-point to use  */
        if (VALID_CONS_TARGET(ct)) {
                /* apply offset to target location */
                add_v3_v3v3(pivot, ct->matrix[3], data->offset);
        }
        else {
                /* no targets to worry about... */
                if ((data->flag & PIVOTCON_FLAG_OFFSET_ABS) == 0) {
                        /* offset is relative to owner */
                        add_v3_v3v3(pivot, cob->matrix[3], data->offset);
                }
                else {
                        /* directly use the 'offset' specified as an absolute position instead */
                        copy_v3_v3(pivot, data->offset);
                }
        }
        
        /* get rotation matrix representing the rotation of the owner */
        // TODO: perhaps we might want to include scaling based on the pivot too?
        copy_m3_m4(rotMat, cob->matrix);
        normalize_m3(rotMat);


        /* correct the pivot by the rotation axis otherwise the pivot translates when it shouldnt */
        mat3_to_axis_angle(axis, &angle, rotMat);
        if(angle) {
                float dvec[3];
                sub_v3_v3v3(vec, pivot, cob->matrix[3]);
                project_v3_v3v3(dvec, vec, axis);
                sub_v3_v3(pivot, dvec);
        }

        /* perform the pivoting... */
                /* 1. take the vector from owner to the pivot */
        sub_v3_v3v3(vec, cob->matrix[3], pivot);
                /* 2. rotate this vector by the rotation of the object... */
        mul_m3_v3(rotMat, vec);
                /* 3. make the rotation in terms of the pivot now */
        add_v3_v3v3(cob->matrix[3], pivot, vec);
}


static bConstraintTypeInfo CTI_PIVOT = {
        CONSTRAINT_TYPE_PIVOT, /* type */
        sizeof(bPivotConstraint), /* size */
        "Pivot", /* name */
        "bPivotConstraint", /* struct name */
        NULL, /* free data */
        NULL, /* relink data */
        pivotcon_id_looper, /* id looper */
        NULL, /* copy data */
        NULL, /* new data */ // XXX: might be needed to get 'normal' pivot behaviour...
        pivotcon_get_tars, /* get constraint targets */
        pivotcon_flush_tars, /* flush constraint targets */
        default_get_tarmat, /* get target matrix */
        pivotcon_evaluate /* evaluate */
};

/* ************************* Constraints Type-Info *************************** */
/* All of the constraints api functions use bConstraintTypeInfo structs to carry out
 * and operations that involve constraint specific code.
 */

/* These globals only ever get directly accessed in this file */
static bConstraintTypeInfo *constraintsTypeInfo[NUM_CONSTRAINT_TYPES];
static short CTI_INIT= 1; /* when non-zero, the list needs to be updated */

/* This function only gets called when CTI_INIT is non-zero */
static void constraints_init_typeinfo (void) {
        constraintsTypeInfo[0]=  NULL;                                  /* 'Null' Constraint */
        constraintsTypeInfo[1]=  &CTI_CHILDOF;                  /* ChildOf Constraint */
        constraintsTypeInfo[2]=  &CTI_TRACKTO;                  /* TrackTo Constraint */
        constraintsTypeInfo[3]=  &CTI_KINEMATIC;                /* IK Constraint */
        constraintsTypeInfo[4]=  &CTI_FOLLOWPATH;               /* Follow-Path Constraint */
        constraintsTypeInfo[5]=  &CTI_ROTLIMIT;                 /* Limit Rotation Constraint */
        constraintsTypeInfo[6]=  &CTI_LOCLIMIT;                 /* Limit Location Constraint */
        constraintsTypeInfo[7]=  &CTI_SIZELIMIT;                /* Limit Scaling Constraint */
        constraintsTypeInfo[8]=  &CTI_ROTLIKE;                  /* Copy Rotation Constraint */
        constraintsTypeInfo[9]=  &CTI_LOCLIKE;                  /* Copy Location Constraint */
        constraintsTypeInfo[10]= &CTI_SIZELIKE;                 /* Copy Scaling Constraint */
        constraintsTypeInfo[11]= &CTI_PYTHON;                   /* Python/Script Constraint */
        constraintsTypeInfo[12]= &CTI_ACTION;                   /* Action Constraint */
        constraintsTypeInfo[13]= &CTI_LOCKTRACK;                /* Locked-Track Constraint */
        constraintsTypeInfo[14]= &CTI_DISTLIMIT;                /* Limit Distance Constraint */
        constraintsTypeInfo[15]= &CTI_STRETCHTO;                /* StretchTo Constaint */ 
        constraintsTypeInfo[16]= &CTI_MINMAX;                   /* Floor Constraint */
        constraintsTypeInfo[17]= &CTI_RIGIDBODYJOINT;   /* RigidBody Constraint */
        constraintsTypeInfo[18]= &CTI_CLAMPTO;                  /* ClampTo Constraint */        
        constraintsTypeInfo[19]= &CTI_TRANSFORM;                /* Transformation Constraint */
        constraintsTypeInfo[20]= &CTI_SHRINKWRAP;               /* Shrinkwrap Constraint */
        constraintsTypeInfo[21]= &CTI_DAMPTRACK;                /* Damped TrackTo Constraint */
        constraintsTypeInfo[22]= &CTI_SPLINEIK;                 /* Spline IK Constraint */
        constraintsTypeInfo[23]= &CTI_TRANSLIKE;                /* Copy Transforms Constraint */
        constraintsTypeInfo[24]= &CTI_SAMEVOL;                  /* Maintain Volume Constraint */
        constraintsTypeInfo[25]= &CTI_PIVOT;                    /* Pivot Constraint */
}

/* This function should be used for getting the appropriate type-info when only
 * a constraint type is known
 */
bConstraintTypeInfo *get_constraint_typeinfo (int type)
{
        /* initialise the type-info list? */
        if (CTI_INIT) {
                constraints_init_typeinfo();
                CTI_INIT = 0;
        }
        
        /* only return for valid types */
        if ( (type >= CONSTRAINT_TYPE_NULL) && 
                 (type < NUM_CONSTRAINT_TYPES ) ) 
        {
                /* there shouldn't be any segfaults here... */
                return constraintsTypeInfo[type];
        }
        else {
                printf("No valid constraint type-info data available. Type = %i \n", type);
        }
        
        return NULL;
} 
 
/* This function should always be used to get the appropriate type-info, as it
 * has checks which prevent segfaults in some weird cases.
 */
bConstraintTypeInfo *constraint_get_typeinfo (bConstraint *con)
{
        /* only return typeinfo for valid constraints */
        if (con)
                return get_constraint_typeinfo(con->type);
        else
                return NULL;
}

/* ************************* General Constraints API ************************** */
/* The functions here are called by various parts of Blender. Very few (should be none if possible)
 * constraint-specific code should occur here.
 */
 
/* ---------- Data Management ------- */

/* Free data of a specific constraint if it has any info.
 * be sure to run BIK_clear_data() when freeing an IK constraint,
 * unless DAG_scene_sort is called. */
void free_constraint_data (bConstraint *con)
{
        if (con->data) {
                bConstraintTypeInfo *cti= constraint_get_typeinfo(con);
                
                /* perform any special freeing constraint may have */
                if (cti && cti->free_data)
                        cti->free_data(con);
                
                /* free constraint data now */
                MEM_freeN(con->data);
        }
}

/* Free all constraints from a constraint-stack */
void free_constraints (ListBase *list)
{
        bConstraint *con;
        
        /* Free constraint data and also any extra data */
        for (con= list->first; con; con= con->next)
                free_constraint_data(con);
        
        /* Free the whole list */
        BLI_freelistN(list);
}


/* Remove the specified constraint from the given constraint stack */
int remove_constraint (ListBase *list, bConstraint *con)
{
        if (con) {
                free_constraint_data(con);
                BLI_freelinkN(list, con);
                return 1;
        }
        else
                return 0;
}

/* Remove all the constraints of the specified type from the given constraint stack */
void remove_constraints_type (ListBase *list, short type, short last_only)
{
        bConstraint *con, *conp;
        
        if (list == NULL)
                return;
        
        /* remove from the end of the list to make it faster to find the last instance */
        for (con= list->last; con; con= conp) {
                conp= con->prev;
                
                if (con->type == type) {
                        remove_constraint(list, con);
                        if (last_only) 
                                return;
                }
        }
}

/* ......... */

/* Creates a new constraint, initialises its data, and returns it */
static bConstraint *add_new_constraint_internal (const char *name, short type)
{
        bConstraint *con= MEM_callocN(sizeof(bConstraint), "Constraint");
        bConstraintTypeInfo *cti= get_constraint_typeinfo(type);
        const char *newName;

        /* Set up a generic constraint datablock */
        con->type = type;
        con->flag |= CONSTRAINT_EXPAND;
        con->enforce = 1.0f;

        /* Determine a basic name, and info */
        if (cti) {
                /* initialise constraint data */
                con->data = MEM_callocN(cti->size, cti->structName);
                
                /* only constraints that change any settings need this */
                if (cti->new_data)
                        cti->new_data(con->data);
                
                /* if no name is provided, use the type of the constraint as the name */
                newName= (name && name[0]) ? name : cti->name;
        }
        else {
                /* if no name is provided, use the generic "Const" name */
                // NOTE: any constraint type that gets here really shouldn't get added...
                newName= (name && name[0]) ? name : "Const";
        }
        
        /* copy the name */
        BLI_strncpy(con->name, newName, sizeof(con->name));
        
        /* return the new constraint */
        return con;
}

/* if pchan is not NULL then assume we're adding a pose constraint */
static bConstraint *add_new_constraint (Object *ob, bPoseChannel *pchan, const char *name, short type)
{
        bConstraint *con;
        ListBase *list;
        
        /* add the constraint */
        con= add_new_constraint_internal(name, type);
        
        /* find the constraint stack - bone or object? */
        list = (pchan) ? (&pchan->constraints) : (&ob->constraints);
        
        if (list) {
                /* add new constraint to end of list of constraints before ensuring that it has a unique name
                 * (otherwise unique-naming code will fail, since it assumes element exists in list)
                 */
                BLI_addtail(list, con);
                unique_constraint_name(con, list);
                
                /* if the target list is a list on some PoseChannel belonging to a proxy-protected
                 * Armature layer, we must tag newly added constraints with a flag which allows them
                 * to persist after proxy syncing has been done
                 */
                if (proxylocked_constraints_owner(ob, pchan))
                        con->flag |= CONSTRAINT_PROXY_LOCAL;
                
                /* make this constraint the active one */
                constraints_set_active(list, con);
        }
        
        /* set type+owner specific immutable settings */
        // TODO: does action constraint need anything here - i.e. spaceonce?
        switch (type) {
                case CONSTRAINT_TYPE_CHILDOF:
                {
                        /* if this constraint is being added to a posechannel, make sure
                         * the constraint gets evaluated in pose-space */
                        if (pchan) {
                                con->ownspace = CONSTRAINT_SPACE_POSE;
                                con->flag |= CONSTRAINT_SPACEONCE;
                        }
                }
                        break;
        }
        
        return con;
}

/* ......... */

/* Add new constraint for the given bone */
bConstraint *add_pose_constraint (Object *ob, bPoseChannel *pchan, const char *name, short type)
{
        if (pchan == NULL)
                return NULL;
        
        return add_new_constraint(ob, pchan, name, type);
}

/* Add new constraint for the given object */
bConstraint *add_ob_constraint(Object *ob, const char *name, short type)
{
        return add_new_constraint(ob, NULL, name, type);
}

/* ......... */

/* Reassign links that constraints have to other data (called during file loading?) */
void relink_constraints (ListBase *conlist)
{
        bConstraint *con;
        bConstraintTarget *ct;
        
        for (con= conlist->first; con; con= con->next) {
                bConstraintTypeInfo *cti= constraint_get_typeinfo(con);
                
                if (cti) {
                        /* relink any targets */
                        if (cti->get_constraint_targets) {
                                ListBase targets = {NULL, NULL};
                                
                                cti->get_constraint_targets(con, &targets);
                                for (ct= targets.first; ct; ct= ct->next) {
                                        ID_NEW(ct->tar);
                                }
                                
                                if (cti->flush_constraint_targets)
                                        cti->flush_constraint_targets(con, &targets, 0);
                        }
                        
                        /* relink any other special data */
                        if (cti->relink_data)
                                cti->relink_data(con);
                }
        }
}

/* Run the given callback on all ID-blocks in list of constraints */
void id_loop_constraints (ListBase *conlist, ConstraintIDFunc func, void *userdata)
{
        bConstraint *con;
        
        for (con= conlist->first; con; con= con->next) {
                bConstraintTypeInfo *cti= constraint_get_typeinfo(con);
                
                if (cti) {
                        if (cti->id_looper)
                                cti->id_looper(con, func, userdata);
                }
        }
}

/* ......... */

/* helper for copy_constraints(), to be used for making sure that ID's are valid */
static void con_extern_cb(bConstraint *UNUSED(con), ID **idpoin, void *UNUSED(userData))
{
        if (*idpoin && (*idpoin)->lib)
                id_lib_extern(*idpoin);
}

/* duplicate all of the constraints in a constraint stack */
void copy_constraints (ListBase *dst, const ListBase *src, int do_extern)
{
        bConstraint *con, *srccon;
        
        dst->first= dst->last= NULL;
        BLI_duplicatelist(dst, src);
        
        for (con=dst->first, srccon=src->first; con && srccon; srccon=srccon->next, con=con->next) {
                bConstraintTypeInfo *cti= constraint_get_typeinfo(con);
                
                /* make a new copy of the constraint's data */
                con->data = MEM_dupallocN(con->data);
                
                /* only do specific constraints if required */
                if (cti) {
                        /* perform custom copying operations if needed */
                        if (cti->copy_data)
                                cti->copy_data(con, srccon);
                        
                        /* for proxies we dont want to make extern */
                        if (do_extern) {
                                /* go over used ID-links for this constraint to ensure that they are valid for proxies */
                                if (cti->id_looper)
                                        cti->id_looper(con, con_extern_cb, NULL);
                        }
                }
        }
}

/* ......... */

bConstraint *constraints_findByName(ListBase *list, const char *name)
{
        return BLI_findstring(list, name, offsetof(bConstraint, name));
}

/* finds the 'active' constraint in a constraint stack */
bConstraint *constraints_get_active (ListBase *list)
{
        bConstraint *con;
        
        /* search for the first constraint with the 'active' flag set */
        if (list) {
                for (con= list->first; con; con= con->next) {
                        if (con->flag & CONSTRAINT_ACTIVE)
                                return con;
                }
        }
        
        /* no active constraint found */
        return NULL;
}

/* Set the given constraint as the active one (clearing all the others) */
void constraints_set_active (ListBase *list, bConstraint *con)
{
        bConstraint *c;
        
        if (list) {
                for (c= list->first; c; c= c->next) {
                        if (c == con) 
                                c->flag |= CONSTRAINT_ACTIVE;
                        else 
                                c->flag &= ~CONSTRAINT_ACTIVE;
                }
        }
}

/* -------- Constraints and Proxies ------- */

/* Rescue all constraints tagged as being CONSTRAINT_PROXY_LOCAL (i.e. added to bone that's proxy-synced in this file) */
void extract_proxylocal_constraints (ListBase *dst, ListBase *src)
{
        bConstraint *con, *next;
        
        /* for each tagged constraint, remove from src and move to dst */
        for (con= src->first; con; con= next) {
                next= con->next;
                
                /* check if tagged */
                if (con->flag & CONSTRAINT_PROXY_LOCAL) {
                        BLI_remlink(src, con);
                        BLI_addtail(dst, con);
                }
        }
}

/* Returns if the owner of the constraint is proxy-protected */
short proxylocked_constraints_owner (Object *ob, bPoseChannel *pchan)
{
        /* Currently, constraints can only be on object or bone level */
        if (ob && ob->proxy) {
                if (ob->pose && pchan) {
                        bArmature *arm= ob->data;
                        
                        /* On bone-level, check if bone is on proxy-protected layer */
                        if ((pchan->bone) && (pchan->bone->layer & arm->layer_protected))
                                return 1;
                }
                else {
                        /* FIXME: constraints on object-level are not handled well yet */
                        return 1;
                }       
        }
        
        return 0;
}

/* -------- Target-Matrix Stuff ------- */

/* This function is a relic from the prior implementations of the constraints system, when all
 * constraints either had one or no targets. It used to be called during the main constraint solving
 * loop, but is now only used for the remaining cases for a few constraints. 
 *
 * None of the actual calculations of the matricies should be done here! Also, this function is 
 * not to be used by any new constraints, particularly any that have multiple targets.
 */
void get_constraint_target_matrix (struct Scene *scene, bConstraint *con, int n, short ownertype, void *ownerdata, float mat[][4], float ctime)
{
        bConstraintTypeInfo *cti= constraint_get_typeinfo(con);
        ListBase targets = {NULL, NULL};
        bConstraintOb *cob;
        bConstraintTarget *ct;
        
        if (cti && cti->get_constraint_targets) {
                /* make 'constraint-ob' */
                cob= MEM_callocN(sizeof(bConstraintOb), "tempConstraintOb");
                cob->type= ownertype;
                cob->scene = scene;
                switch (ownertype) {
                        case CONSTRAINT_OBTYPE_OBJECT: /* it is usually this case */
                        {
                                cob->ob= (Object *)ownerdata;
                                cob->pchan= NULL;
                                if (cob->ob) {
                                        copy_m4_m4(cob->matrix, cob->ob->obmat);
                                        copy_m4_m4(cob->startmat, cob->matrix);
                                }
                                else {
                                        unit_m4(cob->matrix);
                                        unit_m4(cob->startmat);
                                }
                        }       
                                break;
                        case CONSTRAINT_OBTYPE_BONE: /* this may occur in some cases */
                        {
                                cob->ob= NULL; /* this might not work at all :/ */
                                cob->pchan= (bPoseChannel *)ownerdata;
                                if (cob->pchan) {
                                        copy_m4_m4(cob->matrix, cob->pchan->pose_mat);
                                        copy_m4_m4(cob->startmat, cob->matrix);
                                }
                                else {
                                        unit_m4(cob->matrix);
                                        unit_m4(cob->startmat);
                                }
                        }
                                break;
                }
                
                /* get targets - we only need the first one though (and there should only be one) */
                cti->get_constraint_targets(con, &targets);
                
                /* only calculate the target matrix on the first target */
                ct= (bConstraintTarget *)targets.first;
                while(ct && n-- > 0)
                        ct= ct->next;

                if (ct) {
                        if (cti->get_target_matrix)
                                cti->get_target_matrix(con, cob, ct, ctime);
                        copy_m4_m4(mat, ct->matrix);
                }
                
                /* free targets + 'constraint-ob' */
                if (cti->flush_constraint_targets)
                        cti->flush_constraint_targets(con, &targets, 1);
                MEM_freeN(cob);
        }
        else {
                /* invalid constraint - perhaps... */
                unit_m4(mat);
        }
}
 
/* ---------- Evaluation ----------- */

/* This function is called whenever constraints need to be evaluated. Currently, all
 * constraints that can be evaluated are everytime this gets run.
 *
 * constraints_make_evalob and constraints_clear_evalob should be called before and 
 * after running this function, to sort out cob
 */
void solve_constraints (ListBase *conlist, bConstraintOb *cob, float ctime)
{
        bConstraint *con;
        float oldmat[4][4];
        float enf;

        /* check that there is a valid constraint object to evaluate */
        if (cob == NULL)
                return;
        
        /* loop over available constraints, solving and blending them */
        for (con= conlist->first; con; con= con->next) {
                bConstraintTypeInfo *cti= constraint_get_typeinfo(con);
                ListBase targets = {NULL, NULL};
                
                /* these we can skip completely (invalid constraints...) */
                if (cti == NULL) continue;
                if (con->flag & (CONSTRAINT_DISABLE|CONSTRAINT_OFF)) continue;
                /* these constraints can't be evaluated anyway */
                if (cti->evaluate_constraint == NULL) continue;
                /* influence == 0 should be ignored */
                if (con->enforce == 0.0f) continue;
                
                /* influence of constraint
                 *      - value should have been set from animation data already
                 */
                enf = con->enforce;
                
                /* make copy of worldspace matrix pre-constraint for use with blending later */
                copy_m4_m4(oldmat, cob->matrix);
                
                /* move owner matrix into right space */
                constraint_mat_convertspace(cob->ob, cob->pchan, cob->matrix, CONSTRAINT_SPACE_WORLD, con->ownspace);
                
                /* prepare targets for constraint solving */
                if (cti->get_constraint_targets) {
                        bConstraintTarget *ct;
                        
                        /* get targets 
                         *      - constraints should use ct->matrix, not directly accessing values
                         *      - ct->matrix members have not yet been calculated here! 
                         */
                        cti->get_constraint_targets(con, &targets);
                        
                        /* set matrices 
                         *      - calculate if possible, otherwise just initialise as identity matrix 
                         */
                        if (cti->get_target_matrix) {
                                for (ct= targets.first; ct; ct= ct->next) 
                                        cti->get_target_matrix(con, cob, ct, ctime);
                        }
                        else {
                                for (ct= targets.first; ct; ct= ct->next)
                                        unit_m4(ct->matrix);
                        }
                }
                
                /* Solve the constraint and put result in cob->matrix */
                cti->evaluate_constraint(con, cob, &targets);
                
                /* clear targets after use 
                 *      - this should free temp targets but no data should be copied back
                 *        as constraints may have done some nasty things to it...
                 */
                if (cti->flush_constraint_targets) {
                        cti->flush_constraint_targets(con, &targets, 1);
                }
                
                /* move owner back into worldspace for next constraint/other business */
                if ((con->flag & CONSTRAINT_SPACEONCE) == 0) 
                        constraint_mat_convertspace(cob->ob, cob->pchan, cob->matrix, con->ownspace, CONSTRAINT_SPACE_WORLD);
                        
                /* Interpolate the enforcement, to blend result of constraint into final owner transform 
                 *      - all this happens in worldspace to prevent any weirdness creeping in ([#26014] and [#25725]),
                 *        since some constraints may not convert the solution back to the input space before blending
                 *        but all are guaranteed to end up in good "worldspace" result
                 */
                /* Note: all kind of stuff here before (caused trouble), much easier to just interpolate, or did I miss something? -jahka */
                if (enf < 1.0f) {
                        float solution[4][4];
                        copy_m4_m4(solution, cob->matrix);
                        blend_m4_m4m4(cob->matrix, oldmat, solution, enf);
                }
        }
}