volume_precache.c

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/*
 *
 * ***** 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): Matt Ebb, Ra˙l Fern·ndez Hern·ndez (Farsthary).
 *
 * ***** END GPL LICENSE BLOCK *****
 */

#include <math.h>
#include <stdlib.h>
#include <string.h>
#include <float.h>

#include "MEM_guardedalloc.h"

#include "BLI_blenlib.h"
#include "BLI_math.h"
#include "BLI_threads.h"
#include "BLI_voxel.h"
#include "BLI_utildefines.h"

#include "PIL_time.h"

#include "RE_shader_ext.h"

#include "DNA_material_types.h"

#include "rayintersection.h"
#include "rayobject.h"
#include "render_types.h"
#include "rendercore.h"
#include "renderdatabase.h"
#include "volumetric.h"
#include "volume_precache.h"

#if defined( _MSC_VER ) && !defined( __cplusplus )
# define inline __inline
#endif // defined( _MSC_VER ) && !defined( __cplusplus )

#include "BKE_global.h"

/* ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ */
/* defined in pipeline.c, is hardcopy of active dynamic allocated Render */
/* only to be used here in this file, it's for speed */
extern struct Render R;
/* ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ */

/* *** utility code to set up an individual raytree for objectinstance, for checking inside/outside *** */

/* Recursive test for intersections, from a point inside the mesh, to outside
 * Number of intersections (depth) determine if a point is inside or outside the mesh */
static int intersect_outside_volume(RayObject *tree, Isect *isect, float *offset, int limit, int depth)
{
        if (limit == 0) return depth;
        
        if (RE_rayobject_raycast(tree, isect)) {
                
                isect->start[0] = isect->start[0] + isect->dist*isect->dir[0];
                isect->start[1] = isect->start[1] + isect->dist*isect->dir[1];
                isect->start[2] = isect->start[2] + isect->dist*isect->dir[2];
                
                isect->dist = FLT_MAX;
                isect->skip = RE_SKIP_VLR_NEIGHBOUR;
                isect->orig.face= isect->hit.face;
                isect->orig.ob= isect->hit.ob;
                
                return intersect_outside_volume(tree, isect, offset, limit-1, depth+1);
        } else {
                return depth;
        }
}

/* Uses ray tracing to check if a point is inside or outside an ObjectInstanceRen */
static int point_inside_obi(RayObject *tree, ObjectInstanceRen *UNUSED(obi), float *co)
{
        Isect isect= {{0}};
        float dir[3] = {0.0f,0.0f,1.0f};
        int final_depth=0, depth=0, limit=20;
        
        /* set up the isect */
        VECCOPY(isect.start, co);
        VECCOPY(isect.dir, dir);
        isect.mode= RE_RAY_MIRROR;
        isect.last_hit= NULL;
        isect.lay= -1;
        
        isect.dist = FLT_MAX;
        isect.orig.face= NULL;
        isect.orig.ob = NULL;

        final_depth = intersect_outside_volume(tree, &isect, dir, limit, depth);
        
        /* even number of intersections: point is outside
         * odd number: point is inside */
        if (final_depth % 2 == 0) return 0;
        else return 1;
}

/* find the bounding box of an objectinstance in global space */
void global_bounds_obi(Render *re, ObjectInstanceRen *obi, float *bbmin, float *bbmax)
{
        ObjectRen *obr = obi->obr;
        VolumePrecache *vp = obi->volume_precache;
        VertRen *ver= NULL;
        float co[3];
        int a;
        
        if (vp->bbmin != NULL && vp->bbmax != NULL) {
                copy_v3_v3(bbmin, vp->bbmin);
                copy_v3_v3(bbmax, vp->bbmax);
                return;
        }
        
        vp->bbmin = MEM_callocN(sizeof(float)*3, "volume precache min boundbox corner");
        vp->bbmax = MEM_callocN(sizeof(float)*3, "volume precache max boundbox corner");
        
        INIT_MINMAX(bbmin, bbmax);
        
        for(a=0; a<obr->totvert; a++) {
                if((a & 255)==0) ver= obr->vertnodes[a>>8].vert;
                else ver++;
                
                copy_v3_v3(co, ver->co);
                
                /* transformed object instance in camera space */
                if(obi->flag & R_TRANSFORMED)
                        mul_m4_v3(obi->mat, co);
                
                /* convert to global space */
                mul_m4_v3(re->viewinv, co);
                
                DO_MINMAX(co, vp->bbmin, vp->bbmax);
        }
        
        copy_v3_v3(bbmin, vp->bbmin);
        copy_v3_v3(bbmax, vp->bbmax);
        
}

/* *** light cache filtering *** */

static float get_avg_surrounds(float *cache, int *res, int xx, int yy, int zz)
{
        int x, y, z, x_, y_, z_;
        int added=0;
        float tot=0.0f;
        
        for (z=-1; z <= 1; z++) {
                z_ = zz+z;
                if (z_ >= 0 && z_ <= res[2]-1) {
                
                        for (y=-1; y <= 1; y++) {
                                y_ = yy+y;
                                if (y_ >= 0 && y_ <= res[1]-1) {
                                
                                        for (x=-1; x <= 1; x++) {
                                                x_ = xx+x;
                                                if (x_ >= 0 && x_ <= res[0]-1) {
                                                        const int i= V_I(x_, y_, z_, res);
                                                        
                                                        if (cache[i] > 0.0f) {
                                                                tot += cache[i];
                                                                added++;
                                                        }
                                                        
                                                }
                                        }
                                }
                        }
                }
        }
        
        if (added > 0) tot /= added;
        
        return tot;
}

/* function to filter the edges of the light cache, where there was no volume originally.
 * For each voxel which was originally external to the mesh, it finds the average values of
 * the surrounding internal voxels and sets the original external voxel to that average amount.
 * Works almost a bit like a 'dilate' filter */
static void lightcache_filter(VolumePrecache *vp)
{
        int x, y, z;

        for (z=0; z < vp->res[2]; z++) {
                for (y=0; y < vp->res[1]; y++) {
                        for (x=0; x < vp->res[0]; x++) {
                                /* trigger for outside mesh */
                                const int i= V_I(x, y, z, vp->res);
                                
                                if (vp->data_r[i] < -0.f)
                                        vp->data_r[i] = get_avg_surrounds(vp->data_r, vp->res, x, y, z);
                                if (vp->data_g[i] < -0.f)
                                        vp->data_g[i] = get_avg_surrounds(vp->data_g, vp->res, x, y, z);
                                if (vp->data_b[i] < -0.f)
                                        vp->data_b[i] = get_avg_surrounds(vp->data_b, vp->res, x, y, z);
                        }
                }
        }
}

#if 0
static void lightcache_filter2(VolumePrecache *vp)
{
        int x, y, z;
        float *new_r, *new_g, *new_b;
        int field_size = vp->res[0]*vp->res[1]*vp->res[2]*sizeof(float);
        
        new_r = MEM_mallocN(field_size, "temp buffer for light cache filter r channel");
        new_g = MEM_mallocN(field_size, "temp buffer for light cache filter g channel");
        new_b = MEM_mallocN(field_size, "temp buffer for light cache filter b channel");
        
        memcpy(new_r, vp->data_r, field_size);
        memcpy(new_g, vp->data_g, field_size);
        memcpy(new_b, vp->data_b, field_size);
        
        for (z=0; z < vp->res[2]; z++) {
                for (y=0; y < vp->res[1]; y++) {
                        for (x=0; x < vp->res[0]; x++) {
                                /* trigger for outside mesh */
                                const int i= V_I(x, y, z, vp->res);
                                if (vp->data_r[i] < -0.f)
                                        new_r[i] = get_avg_surrounds(vp->data_r, vp->res, x, y, z);
                                if (vp->data_g[i] < -0.f)
                                        new_g[i] = get_avg_surrounds(vp->data_g, vp->res, x, y, z);
                                if (vp->data_b[i] < -0.f)
                                        new_b[i] = get_avg_surrounds(vp->data_b, vp->res, x, y, z);
                        }
                }
        }
        
        SWAP(float *, vp->data_r, new_r);
        SWAP(float *, vp->data_g, new_g);
        SWAP(float *, vp->data_b, new_b);
        
        if (new_r) { MEM_freeN(new_r); new_r=NULL; }
        if (new_g) { MEM_freeN(new_g); new_g=NULL; }
        if (new_b) { MEM_freeN(new_b); new_b=NULL; }
}
#endif

static inline int ms_I(int x, int y, int z, int *n) //has a pad of 1 voxel surrounding the core for boundary simulation
{ 
        /* different ordering to light cache */
        return x*(n[1]+2)*(n[2]+2) + y*(n[2]+2) + z;    
}

static inline int v_I_pad(int x, int y, int z, int *n) //has a pad of 1 voxel surrounding the core for boundary simulation
{ 
        /* same ordering to light cache, with padding */
        return z*(n[1]+2)*(n[0]+2) + y*(n[0]+2) + x;    
}

static inline int lc_to_ms_I(int x, int y, int z, int *n)
{ 
        /* converting light cache index to multiple scattering index */
        return (x-1)*(n[1]*n[2]) + (y-1)*(n[2]) + z-1;
}

/* *** multiple scattering approximation *** */

/* get the total amount of light energy in the light cache. used to normalise after multiple scattering */
static float total_ss_energy(VolumePrecache *vp)
{
        int x, y, z;
        int *res = vp->res;
        float energy=0.f;
        
        for (z=0; z < res[2]; z++) {
                for (y=0; y < res[1]; y++) {
                        for (x=0; x < res[0]; x++) {
                                const int i=V_I(x, y, z, res);
                        
                                if (vp->data_r[i] > 0.f) energy += vp->data_r[i];
                                if (vp->data_g[i] > 0.f) energy += vp->data_g[i];
                                if (vp->data_b[i] > 0.f) energy += vp->data_b[i];
                        }
                }
        }
        
        return energy;
}

static float total_ms_energy(float *sr, float *sg, float *sb, int *res)
{
        int x, y, z;
        float energy=0.f;
        
        for (z=1;z<=res[2];z++) {
                for (y=1;y<=res[1];y++) {
                        for (x=1;x<=res[0];x++) {
                                const int i = ms_I(x,y,z,res);
                                
                                if (sr[i] > 0.f) energy += sr[i];
                                if (sg[i] > 0.f) energy += sg[i];
                                if (sb[i] > 0.f) energy += sb[i];
                        }
                }
        }
        
        return energy;
}

static void ms_diffuse(float *x0, float *x, float diff, int *n) //n is the unpadded resolution
{
        int i, j, k, l;
        const float dt = VOL_MS_TIMESTEP;
        const float a = dt*diff*n[0]*n[1]*n[2];
        
        for (l=0; l<20; l++)
        {
                for (k=1; k<=n[2]; k++)
                {
                        for (j=1; j<=n[1]; j++)
                        {
                                for (i=1; i<=n[0]; i++)
                                {
                                   x[v_I_pad(i,j,k,n)] = (x0[v_I_pad(i,j,k,n)]) + a*(   x0[v_I_pad(i-1,j,k,n)]+ x0[v_I_pad(i+1,j,k,n)]+ x0[v_I_pad(i,j-1,k,n)]+
                                                                                                                                                x0[v_I_pad(i,j+1,k,n)]+ x0[v_I_pad(i,j,k-1,n)]+x0[v_I_pad(i,j,k+1,n)]
                                                                                                                                                ) / (1+6*a);
                                }
                        }
                }
        }
}

static void multiple_scattering_diffusion(Render *re, VolumePrecache *vp, Material *ma)
{
        const float diff = ma->vol.ms_diff * 0.001f;    /* compensate for scaling for a nicer UI range */
        const int simframes = (int)(ma->vol.ms_spread * (float)MAX3(vp->res[0], vp->res[1], vp->res[2]));
        const int shade_type = ma->vol.shade_type;
        float fac = ma->vol.ms_intensity;
        
        int x, y, z, m;
        int *n = vp->res;
        const int size = (n[0]+2)*(n[1]+2)*(n[2]+2);
        double time, lasttime= PIL_check_seconds_timer();
        float total;
        float c=1.0f;
        float origf;    /* factor for blending in original light cache */
        float energy_ss, energy_ms;

        float *sr0=(float *)MEM_callocN(size*sizeof(float), "temporary multiple scattering buffer");
        float *sr=(float *)MEM_callocN(size*sizeof(float), "temporary multiple scattering buffer");
        float *sg0=(float *)MEM_callocN(size*sizeof(float), "temporary multiple scattering buffer");
        float *sg=(float *)MEM_callocN(size*sizeof(float), "temporary multiple scattering buffer");
        float *sb0=(float *)MEM_callocN(size*sizeof(float), "temporary multiple scattering buffer");
        float *sb=(float *)MEM_callocN(size*sizeof(float), "temporary multiple scattering buffer");

        total = (float)(n[0]*n[1]*n[2]*simframes);
        
        energy_ss = total_ss_energy(vp);
        
        /* Scattering as diffusion pass */
        for (m=0; m<simframes; m++)
        {
                /* add sources */
                for (z=1; z<=n[2]; z++)
                {
                        for (y=1; y<=n[1]; y++)
                        {
                                for (x=1; x<=n[0]; x++)
                                {
                                        const int i = lc_to_ms_I(x, y ,z, n);   //lc index                                      
                                        const int j = ms_I(x, y, z, n);                 //ms index
                                        
                                        time= PIL_check_seconds_timer();
                                        c++;                                                                            
                                        if (vp->data_r[i] > 0.0f)
                                                sr[j] += vp->data_r[i];
                                        if (vp->data_g[i] > 0.0f)
                                                sg[j] += vp->data_g[i];
                                        if (vp->data_b[i] > 0.0f)
                                                sb[j] += vp->data_b[i];
                                        
                                        /* Displays progress every second */
                                        if(time-lasttime>1.0f) {
                                                char str[64];
                                                BLI_snprintf(str, sizeof(str), "Simulating multiple scattering: %d%%", (int)(100.0f * (c / total)));
                                                re->i.infostr= str;
                                                re->stats_draw(re->sdh, &re->i);
                                                re->i.infostr= NULL;
                                                lasttime= time;
                                        }
                                }
                        }
                }
                SWAP(float *,sr,sr0);
                SWAP(float *,sg,sg0);
                SWAP(float *,sb,sb0);

                /* main diffusion simulation */
                ms_diffuse(sr0, sr, diff, n);
                ms_diffuse(sg0, sg, diff, n);
                ms_diffuse(sb0, sb, diff, n);
                
                if (re->test_break(re->tbh)) break;
        }
        
        /* normalisation factor to conserve energy */
        energy_ms = total_ms_energy(sr, sg, sb, n);
        fac *= (energy_ss / energy_ms);
        
        /* blend multiple scattering back in the light cache */
        if (shade_type == MA_VOL_SHADE_SHADEDPLUSMULTIPLE) {
                /* conserve energy - half single, half multiple */
                origf = 0.5f;
                fac *= 0.5f;
        } else {
                origf = 0.0f;
        }

        for (z=1;z<=n[2];z++)
        {
                for (y=1;y<=n[1];y++)
                {
                        for (x=1;x<=n[0];x++)
                        {
                                const int i = lc_to_ms_I(x, y ,z, n);   //lc index                                      
                                const int j = ms_I(x, y, z, n);                 //ms index
                                
                                vp->data_r[i] = origf * vp->data_r[i] + fac * sr[j];
                                vp->data_g[i] = origf * vp->data_g[i] + fac * sg[j];
                                vp->data_b[i] = origf * vp->data_b[i] + fac * sb[j];
                        }
                }
        }

        MEM_freeN(sr0);
        MEM_freeN(sr);
        MEM_freeN(sg0);
        MEM_freeN(sg);
        MEM_freeN(sb0);
        MEM_freeN(sb);
}



#if 0 // debug stuff
static void *vol_precache_part_test(void *data)
{
        VolPrecachePart *pa = data;

        printf("part number: %d \n", pa->num);
        printf("done: %d \n", pa->done);
        printf("x min: %d   x max: %d \n", pa->minx, pa->maxx);
        printf("y min: %d   y max: %d \n", pa->miny, pa->maxy);
        printf("z min: %d   z max: %d \n", pa->minz, pa->maxz);

        return NULL;
}
#endif

/* Iterate over the 3d voxel grid, and fill the voxels with scattering information
 *
 * It's stored in memory as 3 big float grids next to each other, one for each RGB channel.
 * I'm guessing the memory alignment may work out better this way for the purposes
 * of doing linear interpolation, but I haven't actually tested this theory! :)
 */
static void *vol_precache_part(void *data)
{
        VolPrecachePart *pa =  (VolPrecachePart *)data;
        ObjectInstanceRen *obi = pa->obi;
        RayObject *tree = pa->tree;
        ShadeInput *shi = pa->shi;
        float scatter_col[3] = {0.f, 0.f, 0.f};
        float co[3], cco[3];
        int x, y, z, i;
        int res[3];

        res[0]= pa->res[0];
        res[1]= pa->res[1];
        res[2]= pa->res[2];

        for (z= pa->minz; z < pa->maxz; z++) {
                co[2] = pa->bbmin[2] + (pa->voxel[2] * (z + 0.5f));
                
                for (y= pa->miny; y < pa->maxy; y++) {
                        co[1] = pa->bbmin[1] + (pa->voxel[1] * (y + 0.5f));
                        
                        for (x=pa->minx; x < pa->maxx; x++) {
                                co[0] = pa->bbmin[0] + (pa->voxel[0] * (x + 0.5f));
                                
                                if (pa->re->test_break && pa->re->test_break(pa->re->tbh))
                                        break;
                                
                                /* convert from world->camera space for shading */
                                mul_v3_m4v3(cco, pa->viewmat, co);
                                
                                i= V_I(x, y, z, res);
                                
                                // don't bother if the point is not inside the volume mesh
                                if (!point_inside_obi(tree, obi, cco)) {
                                        obi->volume_precache->data_r[i] = -1.0f;
                                        obi->volume_precache->data_g[i] = -1.0f;
                                        obi->volume_precache->data_b[i] = -1.0f;
                                        continue;
                                }
                                
                                copy_v3_v3(shi->view, cco);
                                normalize_v3(shi->view);
                                vol_get_scattering(shi, scatter_col, cco);
                        
                                obi->volume_precache->data_r[i] = scatter_col[0];
                                obi->volume_precache->data_g[i] = scatter_col[1];
                                obi->volume_precache->data_b[i] = scatter_col[2];
                                
                        }
                }
        }
        
        pa->done = 1;
        
        return NULL;
}


static void precache_setup_shadeinput(Render *re, ObjectInstanceRen *obi, Material *ma, ShadeInput *shi)
{
        memset(shi, 0, sizeof(ShadeInput)); 
        shi->depth= 1;
        shi->mask= 1;
        shi->mat = ma;
        shi->vlr = NULL;
        memcpy(&shi->r, &shi->mat->r, 23*sizeof(float));        // note, keep this synced with render_types.h
        shi->har= shi->mat->har;
        shi->obi= obi;
        shi->obr= obi->obr;
        shi->lay = re->lay;
}

static void precache_init_parts(Render *re, RayObject *tree, ShadeInput *shi, ObjectInstanceRen *obi, int totthread, int *parts)
{
        VolumePrecache *vp = obi->volume_precache;
        int i=0, x, y, z;
        float voxel[3];
        int sizex, sizey, sizez;
        float bbmin[3], bbmax[3];
        int *res;
        int minx, maxx;
        int miny, maxy;
        int minz, maxz;
        
        if (!vp) return;

        BLI_freelistN(&re->volume_precache_parts);
        
        /* currently we just subdivide the box, number of threads per side */
        parts[0] = parts[1] = parts[2] = totthread;
        res = vp->res;
        
        /* using boundbox in worldspace */
        global_bounds_obi(re, obi, bbmin, bbmax);
        sub_v3_v3v3(voxel, bbmax, bbmin);
        
        voxel[0] /= (float)res[0];
        voxel[1] /= (float)res[1];
        voxel[2] /= (float)res[2];

        for (x=0; x < parts[0]; x++) {
                sizex = ceil(res[0] / (float)parts[0]);
                minx = x * sizex;
                maxx = minx + sizex;
                maxx = (maxx>res[0])?res[0]:maxx;
                
                for (y=0; y < parts[1]; y++) {
                        sizey = ceil(res[1] / (float)parts[1]);
                        miny = y * sizey;
                        maxy = miny + sizey;
                        maxy = (maxy>res[1])?res[1]:maxy;
                        
                        for (z=0; z < parts[2]; z++) {
                                VolPrecachePart *pa= MEM_callocN(sizeof(VolPrecachePart), "new precache part");
                                
                                sizez = ceil(res[2] / (float)parts[2]);
                                minz = z * sizez;
                                maxz = minz + sizez;
                                maxz = (maxz>res[2])?res[2]:maxz;
                                                
                                pa->done = 0;
                                pa->working = 0;
                                
                                pa->re = re;
                                pa->num = i;
                                pa->tree = tree;
                                pa->shi = shi;
                                pa->obi = obi;
                                copy_m4_m4(pa->viewmat, re->viewmat);
                                
                                copy_v3_v3(pa->bbmin, bbmin);
                                copy_v3_v3(pa->voxel, voxel);
                                VECCOPY(pa->res, res);
                                
                                pa->minx = minx; pa->maxx = maxx;
                                pa->miny = miny; pa->maxy = maxy;
                                pa->minz = minz; pa->maxz = maxz;
                                
                                
                                BLI_addtail(&re->volume_precache_parts, pa);
                                
                                i++;
                        }
                }
        }
}

static VolPrecachePart *precache_get_new_part(Render *re)
{
        VolPrecachePart *pa, *nextpa=NULL;
        
        for (pa = re->volume_precache_parts.first; pa; pa=pa->next)
        {
                if (pa->done==0 && pa->working==0) {
                        nextpa = pa;
                        break;
                }
        }

        return nextpa;
}

/* calculate resolution from bounding box in world space */
static int precache_resolution(Render *re, VolumePrecache *vp, ObjectInstanceRen *obi, int res)
{
        float dim[3], div;
        float bbmin[3], bbmax[3];
        
        /* bound box in global space */
        global_bounds_obi(re, obi, bbmin, bbmax);
        sub_v3_v3v3(dim, bbmax, bbmin);
        
        div = MAX3(dim[0], dim[1], dim[2]);
        dim[0] /= div;
        dim[1] /= div;
        dim[2] /= div;
        
        vp->res[0] = ceil(dim[0] * res);
        vp->res[1] = ceil(dim[1] * res);
        vp->res[2] = ceil(dim[2] * res);
        
        if ((vp->res[0] < 1) || (vp->res[1] < 1) || (vp->res[2] < 1))
                return 0;
        
        return 1;
}

/* Precache a volume into a 3D voxel grid.
 * The voxel grid is stored in the ObjectInstanceRen, 
 * in camera space, aligned with the ObjectRen's bounding box.
 * Resolution is defined by the user.
 */
static void vol_precache_objectinstance_threads(Render *re, ObjectInstanceRen *obi, Material *ma)
{
        VolumePrecache *vp;
        VolPrecachePart *nextpa, *pa;
        RayObject *tree;
        ShadeInput shi;
        ListBase threads;
        int parts[3] = {1, 1, 1}, totparts;
        
        int caching=1, counter=0;
        int totthread = re->r.threads;
        
        double time, lasttime= PIL_check_seconds_timer();
        
        R = *re;

        /* create a raytree with just the faces of the instanced ObjectRen, 
         * used for checking if the cached point is inside or outside. */
        tree = makeraytree_object(&R, obi);
        if (!tree) return;

        vp = MEM_callocN(sizeof(VolumePrecache), "volume light cache");
        obi->volume_precache = vp;
        
        if (!precache_resolution(re, vp, obi, ma->vol.precache_resolution)) {
                MEM_freeN(vp);
                vp = NULL;
                return;
        }

        vp->data_r = MEM_callocN(sizeof(float)*vp->res[0]*vp->res[1]*vp->res[2], "volume light cache data red channel");
        vp->data_g = MEM_callocN(sizeof(float)*vp->res[0]*vp->res[1]*vp->res[2], "volume light cache data green channel");
        vp->data_b = MEM_callocN(sizeof(float)*vp->res[0]*vp->res[1]*vp->res[2], "volume light cache data blue channel");
        if (vp->data_r==NULL || vp->data_g==NULL || vp->data_b==NULL) {
                MEM_freeN(vp);
                return;
        }

        /* Need a shadeinput to calculate scattering */
        precache_setup_shadeinput(re, obi, ma, &shi);
        
        precache_init_parts(re, tree, &shi, obi, totthread, parts);
        totparts = parts[0] * parts[1] * parts[2];
        
        BLI_init_threads(&threads, vol_precache_part, totthread);
        
        while(caching) {

                if(BLI_available_threads(&threads) && !(re->test_break(re->tbh))) {
                        nextpa = precache_get_new_part(re);
                        if (nextpa) {
                                nextpa->working = 1;
                                BLI_insert_thread(&threads, nextpa);
                        }
                }
                else PIL_sleep_ms(50);

                caching=0;
                counter=0;
                for(pa= re->volume_precache_parts.first; pa; pa= pa->next) {
                        
                        if(pa->done) {
                                counter++;
                                BLI_remove_thread(&threads, pa);
                        } else
                                caching = 1;
                }
                
                if (re->test_break(re->tbh) && BLI_available_threads(&threads)==totthread)
                        caching=0;
                
                time= PIL_check_seconds_timer();
                if(time-lasttime>1.0f) {
                        char str[64];
                        BLI_snprintf(str, sizeof(str), "Precaching volume: %d%%", (int)(100.0f * ((float)counter / (float)totparts)));
                        re->i.infostr= str;
                        re->stats_draw(re->sdh, &re->i);
                        re->i.infostr= NULL;
                        lasttime= time;
                }
        }
        
        BLI_end_threads(&threads);
        BLI_freelistN(&re->volume_precache_parts);
        
        if(tree) {
                //TODO: makeraytree_object creates a tree and saves it on OBI, if we free this tree we should also clear other pointers to it
                //RE_rayobject_free(tree);
                //tree= NULL;
        }
        
        if (ELEM(ma->vol.shade_type, MA_VOL_SHADE_MULTIPLE, MA_VOL_SHADE_SHADEDPLUSMULTIPLE))
        {
                /* this should be before the filtering */
                multiple_scattering_diffusion(re, obi->volume_precache, ma);
        }
                
        lightcache_filter(obi->volume_precache);
}

static int using_lightcache(Material *ma)
{
        return (((ma->vol.shadeflag & MA_VOL_PRECACHESHADING) && (ma->vol.shade_type == MA_VOL_SHADE_SHADED))
                || (ELEM(ma->vol.shade_type, MA_VOL_SHADE_MULTIPLE, MA_VOL_SHADE_SHADEDPLUSMULTIPLE)));
}

/* loop through all objects (and their associated materials)
 * marked for pre-caching in convertblender.c, and pre-cache them */
void volume_precache(Render *re)
{
        ObjectInstanceRen *obi;
        VolumeOb *vo;

        for(vo= re->volumes.first; vo; vo= vo->next) {
                if (using_lightcache(vo->ma)) {
                        for(obi= re->instancetable.first; obi; obi= obi->next) {
                                if (obi->obr == vo->obr) {
                                        vol_precache_objectinstance_threads(re, obi, vo->ma);
                                }
                        }
                }
        }
        
        re->i.infostr= NULL;
        re->stats_draw(re->sdh, &re->i);
}

void free_volume_precache(Render *re)
{
        ObjectInstanceRen *obi;
        
        for(obi= re->instancetable.first; obi; obi= obi->next) {
                if (obi->volume_precache != NULL) {
                        MEM_freeN(obi->volume_precache->data_r);
                        MEM_freeN(obi->volume_precache->data_g);
                        MEM_freeN(obi->volume_precache->data_b);
                        MEM_freeN(obi->volume_precache->bbmin);
                        MEM_freeN(obi->volume_precache->bbmax);
                        MEM_freeN(obi->volume_precache);
                        obi->volume_precache = NULL;
                }
        }
        
        BLI_freelistN(&re->volumes);
}

int point_inside_volume_objectinstance(Render *re, ObjectInstanceRen *obi, float *co)
{
        RayObject *tree;
        int inside=0;
        
        tree = makeraytree_object(re, obi);
        if (!tree) return 0;
        
        inside = point_inside_obi(tree, obi, co);
        
        //TODO: makeraytree_object creates a tree and saves it on OBI, if we free this tree we should also clear other pointers to it
        //RE_rayobject_free(tree);
        //tree= NULL;
        
        return inside;
}