rayobject_instance.cpp

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/*
 * $Id: rayobject_instance.cpp 35233 2011-02-27 19:31:27Z jesterking $
 *
 * ***** 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) 2009 Blender Foundation.
 * All rights reserved.
 *
 * The Original Code is: all of this file.
 *
 * Contributor(s): André Pinto.
 *
 * ***** END GPL LICENSE BLOCK *****
 */

#include <assert.h>

#include "MEM_guardedalloc.h"

#include "BLI_math.h"
#include "BLI_utildefines.h"

#include "rayintersection.h"
#include "rayobject.h"

#define RE_COST_INSTANCE (1.0f)

static int  RE_rayobject_instance_intersect(RayObject *o, Isect *isec);
static void RE_rayobject_instance_free(RayObject *o);
static void RE_rayobject_instance_bb(RayObject *o, float *min, float *max);
static float RE_rayobject_instance_cost(RayObject *o);

static void RE_rayobject_instance_hint_bb(RayObject *o, RayHint *hint, float *min, float *max)
{}

static RayObjectAPI instance_api =
{
        RE_rayobject_instance_intersect,
        NULL, //static void RE_rayobject_instance_add(RayObject *o, RayObject *ob);
        NULL, //static void RE_rayobject_instance_done(RayObject *o);
        RE_rayobject_instance_free,
        RE_rayobject_instance_bb,
        RE_rayobject_instance_cost,
        RE_rayobject_instance_hint_bb   
};

typedef struct InstanceRayObject
{
        RayObject rayobj;
        RayObject *target;

        void *ob; //Object represented by this instance
        void *target_ob; //Object represented by the inner RayObject, needed to handle self-intersection
        
        float global2target[4][4];
        float target2global[4][4];
        
} InstanceRayObject;


RayObject *RE_rayobject_instance_create(RayObject *target, float transform[][4], void *ob, void *target_ob)
{
        InstanceRayObject *obj= (InstanceRayObject*)MEM_callocN(sizeof(InstanceRayObject), "InstanceRayObject");
        assert( RE_rayobject_isAligned(obj) ); /* RayObject API assumes real data to be 4-byte aligned */       
        
        obj->rayobj.api = &instance_api;
        obj->target = target;
        obj->ob = ob;
        obj->target_ob = target_ob;
        
        copy_m4_m4(obj->target2global, transform);
        invert_m4_m4(obj->global2target, obj->target2global);
        
        return RE_rayobject_unalignRayAPI((RayObject*) obj);
}

static int  RE_rayobject_instance_intersect(RayObject *o, Isect *isec)
{
        InstanceRayObject *obj = (InstanceRayObject*)o;
        float start[3], dir[3], idot_axis[3], dist;
        int changed = 0, i, res;
        
        // TODO - this is disabling self intersection on instances
        if(isec->orig.ob == obj->ob && obj->ob)
        {
                changed = 1;
                isec->orig.ob = obj->target_ob;
        }
        
        // backup old values
        copy_v3_v3(start, isec->start);
        copy_v3_v3(dir, isec->dir);
        copy_v3_v3(idot_axis, isec->idot_axis);
        dist = isec->dist;

        // transform to target coordinates system
        mul_m4_v3(obj->global2target, isec->start);
        mul_mat3_m4_v3(obj->global2target, isec->dir);
        isec->dist *= normalize_v3(isec->dir);
        
        // update idot_axis and bv_index
        for(i=0; i<3; i++)
        {
                isec->idot_axis[i]              = 1.0f / isec->dir[i];
                
                isec->bv_index[2*i]             = isec->idot_axis[i] < 0.0 ? 1 : 0;
                isec->bv_index[2*i+1]   = 1 - isec->bv_index[2*i];
                
                isec->bv_index[2*i]             = i+3*isec->bv_index[2*i];
                isec->bv_index[2*i+1]   = i+3*isec->bv_index[2*i+1];
        }

        // raycast
        res = RE_rayobject_intersect(obj->target, isec);

        // map dist into original coordinate space
        if(res == 0)
        {
                isec->dist = dist;
        }
        else
        {
                // note we don't just multiply dist, because of possible
                // non-uniform scaling in the transform matrix
                float vec[3];

                mul_v3_v3fl(vec, isec->dir, isec->dist);
                mul_mat3_m4_v3(obj->target2global, vec);

                isec->dist = len_v3(vec);
                isec->hit.ob = obj->ob;

#ifdef RT_USE_LAST_HIT  
                // TODO support for last hit optimization in instances that can jump
                // directly to the last hit face.
                // For now it jumps directly to the last-hit instance root node.
                isec->last_hit = RE_rayobject_unalignRayAPI((RayObject*) obj);
#endif
        }

        // restore values
        copy_v3_v3(isec->start, start);
        copy_v3_v3(isec->dir, dir);
        copy_v3_v3(isec->idot_axis, idot_axis);
        
        if(changed)
                isec->orig.ob = obj->ob;

        // restore bv_index
        for(i=0; i<3; i++)
        {
                isec->bv_index[2*i]             = isec->idot_axis[i] < 0.0 ? 1 : 0;
                isec->bv_index[2*i+1]   = 1 - isec->bv_index[2*i];
                
                isec->bv_index[2*i]             = i+3*isec->bv_index[2*i];
                isec->bv_index[2*i+1]   = i+3*isec->bv_index[2*i+1];
        }
                
        return res;
}

static void RE_rayobject_instance_free(RayObject *o)
{
        InstanceRayObject *obj = (InstanceRayObject*)o;
        MEM_freeN(obj);
}

static float RE_rayobject_instance_cost(RayObject *o)
{
        InstanceRayObject *obj = (InstanceRayObject*)o;
        return RE_rayobject_cost(obj->target) + RE_COST_INSTANCE;
}

static void RE_rayobject_instance_bb(RayObject *o, float *min, float *max)
{
        //TODO:
        // *better bb.. calculated without rotations of bb
        // *maybe cache that better-fitted-BB at the InstanceRayObject
        InstanceRayObject *obj = (InstanceRayObject*)o;

        float m[3], M[3], t[3];
        int i, j;
        INIT_MINMAX(m, M);
        RE_rayobject_merge_bb(obj->target, m, M);

        //There must be a faster way than rotating all the 8 vertexs of the BB
        for(i=0; i<8; i++)
        {
                for(j=0; j<3; j++) t[j] = i&(1<<j) ? M[j] : m[j];
                mul_m4_v3(obj->target2global, t);
                DO_MINMAX(t, min, max);
        }
}