Files
test/source/blender/render/intern/source/voxeldata.c
Matt Ebb 71b3088596 Rework of volume shading
After code review and experimentation, this commit makes some changes to the way that volumes are shaded. Previously, there were problems with the 'scattering' component, in that it wasn't physically correct - it didn't conserve energy and was just acting as a brightness multiplier. This has been changed to be more correct, so that as the light is scattered out of the volume, there is less remaining to penetrate through.

Since this behaviour is very similar to absorption but more useful, absorption has been removed and has been replaced by a 'transmission colour' - controlling the colour of light penetrating through the volume after it has been scattered/absorbed. As well as this, there's now 'reflection', a non-physically correct RGB multiplier for out-scattered light. This is handy for tweaking the overall colour of the volume, without having to worry about wavelength dependent absorption, and its effects on transmitted light. Now at least, even though there is the ability to tweak things non-physically, volume shading is physically based by default, and has a better combination of correctness and ease of use.

There's more detailed information and example images here:
http://wiki.blender.org/index.php/User:Broken/VolumeRendering

Also did some tweaks/optimisation:
* Removed shading step size (was a bit annoying, if it comes back, it will be in a different form)
* Removed phase function options, now just one asymmetry slider controls the range between back-scattering, isotropic scattering, and forward scattering. (note, more extreme values gives artifacts with light cache, will fix...)
* Disabled the extra 'bounce lights' from the preview render for volumes, speeds updates significantly
* Enabled voxeldata texture in preview render
* Fixed volume shadows (they were too dark, fixed by avoiding using the shadfac/AddAlphaLight stuff)

More revisions to come later...
2009-09-29 22:01:32 +00:00

339 lines
8.0 KiB
C

/**
*
* ***** 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., 59 Temple Place - Suite 330, Boston, MA 02111-1307, 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): Raul Fernandez Hernandez (Farsthary), Matt Ebb.
*
* ***** END GPL LICENSE BLOCK *****
*/
#include <math.h>
#include <stdlib.h>
#include <stdio.h>
#include "MEM_guardedalloc.h"
#include "BLI_arithb.h"
#include "BLI_blenlib.h"
#include "BLI_voxel.h"
#include "IMB_imbuf.h"
#include "IMB_imbuf_types.h"
#include "BKE_global.h"
#include "BKE_image.h"
#include "BKE_main.h"
#include "BKE_modifier.h"
#include "smoke_API.h"
#include "DNA_texture_types.h"
#include "DNA_object_types.h"
#include "DNA_modifier_types.h"
#include "DNA_smoke_types.h"
#include "render_types.h"
#include "renderdatabase.h"
#include "texture.h"
#include "voxeldata.h"
void load_frame_blendervoxel(FILE *fp, float *F, int size, int frame, int offset)
{
fseek(fp,frame*size*sizeof(float)+offset,0);
fread(F,sizeof(float),size,fp);
}
void load_frame_raw8(FILE *fp, float *F, int size, int frame)
{
char *tmp;
int i;
tmp = (char *)MEM_mallocN(sizeof(char)*size, "temporary voxel file reading storage");
fseek(fp,(frame-1)*size*sizeof(char),0);
fread(tmp, sizeof(char), size, fp);
for (i=0; i<size; i++) {
F[i] = (float)tmp[i] / 256.f;
}
MEM_freeN(tmp);
}
void load_frame_image_sequence(Render *re, VoxelData *vd, Tex *tex)
{
ImBuf *ibuf;
Image *ima = tex->ima;
ImageUser *iuser = &tex->iuser;
int x=0, y=0, z=0;
float *rf;
if (!ima || !iuser) return;
ima->source = IMA_SRC_SEQUENCE;
iuser->framenr = 1 + iuser->offset;
/* find the first valid ibuf and use it to initialise the resolution of the data set */
/* need to do this in advance so we know how much memory to allocate */
ibuf= BKE_image_get_ibuf(ima, iuser);
while (!ibuf && (iuser->framenr < iuser->frames)) {
iuser->framenr++;
ibuf= BKE_image_get_ibuf(ima, iuser);
}
if (!ibuf) return;
if (!ibuf->rect_float) IMB_float_from_rect(ibuf);
vd->flag |= TEX_VD_STILL;
vd->resol[0] = ibuf->x;
vd->resol[1] = ibuf->y;
vd->resol[2] = iuser->frames;
vd->dataset = MEM_mapallocN(sizeof(float)*(vd->resol[0])*(vd->resol[1])*(vd->resol[2]), "voxel dataset");
for (z=0; z < iuser->frames; z++)
{
/* get a new ibuf for each frame */
if (z > 0) {
iuser->framenr++;
ibuf= BKE_image_get_ibuf(ima, iuser);
if (!ibuf) break;
if (!ibuf->rect_float) IMB_float_from_rect(ibuf);
}
rf = ibuf->rect_float;
for (y=0; y < ibuf->y; y++)
{
for (x=0; x < ibuf->x; x++)
{
/* currently converted to monchrome */
vd->dataset[ V_I(x, y, z, vd->resol) ] = (rf[0] + rf[1] + rf[2])*0.333f;
rf +=4;
}
}
BKE_image_free_anim_ibufs(ima, iuser->framenr);
}
}
void write_voxeldata_header(struct VoxelDataHeader *h, FILE *fp)
{
fwrite(h,sizeof(struct VoxelDataHeader),1,fp);
}
void read_voxeldata_header(FILE *fp, struct VoxelData *vd)
{
VoxelDataHeader *h=(VoxelDataHeader *)MEM_mallocN(sizeof(VoxelDataHeader), "voxel data header");
rewind(fp);
fread(h,sizeof(VoxelDataHeader),1,fp);
vd->resol[0]=h->resolX;
vd->resol[1]=h->resolY;
vd->resol[2]=h->resolZ;
MEM_freeN(h);
}
void init_frame_smoke(Render *re, VoxelData *vd, Tex *tex)
{
Object *ob;
ModifierData *md;
vd->dataset = NULL;
if (vd->object == NULL) return;
ob= vd->object;
/* draw code for smoke */
if( (md = (ModifierData *)modifiers_findByType(ob, eModifierType_Smoke)) )
{
SmokeModifierData *smd = (SmokeModifierData *)md;
if(smd->domain && smd->domain->fluid) {
if (smd->domain->flags & MOD_SMOKE_HIGHRES) {
smoke_turbulence_get_res(smd->domain->wt, vd->resol);
vd->dataset = smoke_turbulence_get_density(smd->domain->wt);
} else {
VECCOPY(vd->resol, smd->domain->res);
vd->dataset = smoke_get_density(smd->domain->fluid);
}
}
}
}
void cache_voxeldata(struct Render *re,Tex *tex)
{
VoxelData *vd = tex->vd;
FILE *fp;
int size;
int curframe;
if (!vd) return;
/* image sequence gets special treatment */
if (vd->file_format == TEX_VD_IMAGE_SEQUENCE) {
load_frame_image_sequence(re, vd, tex);
return;
} else if (vd->file_format == TEX_VD_SMOKE) {
init_frame_smoke(re, vd, tex);
return;
}
if (!BLI_exists(vd->source_path)) return;
fp = fopen(vd->source_path,"rb");
if (!fp) return;
if (vd->file_format == TEX_VD_BLENDERVOXEL)
read_voxeldata_header(fp, vd);
size = (vd->resol[0])*(vd->resol[1])*(vd->resol[2]);
vd->dataset = MEM_mapallocN(sizeof(float)*size, "voxel dataset");
if (vd->flag & TEX_VD_STILL) curframe = vd->still_frame;
else curframe = re->r.cfra;
switch(vd->file_format) {
case TEX_VD_BLENDERVOXEL:
load_frame_blendervoxel(fp, vd->dataset, size, curframe-1, sizeof(VoxelDataHeader));
break;
case TEX_VD_RAW_8BIT:
load_frame_raw8(fp, vd->dataset, size, curframe);
break;
}
fclose(fp);
}
void make_voxeldata(struct Render *re)
{
Tex *tex;
re->i.infostr= "Loading voxel datasets";
re->stats_draw(re->sdh, &re->i);
/* XXX: should be doing only textures used in this render */
for (tex= G.main->tex.first; tex; tex= tex->id.next) {
if(tex->id.us && tex->type==TEX_VOXELDATA) {
cache_voxeldata(re, tex);
}
}
re->i.infostr= NULL;
re->stats_draw(re->sdh, &re->i);
}
static void free_voxeldata_one(Render *re, Tex *tex)
{
VoxelData *vd = tex->vd;
if (vd->dataset) {
MEM_freeN(vd->dataset);
vd->dataset = NULL;
}
}
void free_voxeldata(Render *re)
{
Tex *tex;
for (tex= G.main->tex.first; tex; tex= tex->id.next) {
if(tex->id.us && tex->type==TEX_VOXELDATA) {
free_voxeldata_one(re, tex);
}
}
}
int voxeldatatex(struct Tex *tex, float *texvec, struct TexResult *texres)
{
int retval = TEX_INT;
VoxelData *vd = tex->vd;
float co[3], offset[3] = {0.5, 0.5, 0.5};
if ((!vd) || (vd->dataset==NULL)) {
texres->tin = 0.0f;
return 0;
}
/* scale lookup from 0.0-1.0 (original location) to -1.0, 1.0, consistent with image texture tex coords */
/* in implementation this works backwards, bringing sample locations from -1.0, 1.0
* to the range 0.0, 1.0, before looking up in the voxel structure. */
VecCopyf(co, texvec);
VecMulf(co, 0.5f);
VecAddf(co, co, offset);
/* co is now in the range 0.0, 1.0 */
switch (tex->extend) {
case TEX_CLIP:
{
if ((co[0] < 0.f || co[0] > 1.f) || (co[1] < 0.f || co[1] > 1.f) || (co[2] < 0.f || co[2] > 1.f)) {
texres->tin = 0.f;
return retval;
}
break;
}
case TEX_REPEAT:
{
co[0] = co[0] - floor(co[0]);
co[1] = co[1] - floor(co[1]);
co[2] = co[2] - floor(co[2]);
break;
}
case TEX_EXTEND:
{
CLAMP(co[0], 0.f, 1.f);
CLAMP(co[1], 0.f, 1.f);
CLAMP(co[2], 0.f, 1.f);
break;
}
}
switch (vd->interp_type) {
case TEX_VD_NEARESTNEIGHBOR:
texres->tin = voxel_sample_nearest(vd->dataset, vd->resol, co);
break;
case TEX_VD_LINEAR:
texres->tin = voxel_sample_trilinear(vd->dataset, vd->resol, co);
break;
case TEX_VD_QUADRATIC:
texres->tin = voxel_sample_triquadratic(vd->dataset, vd->resol, co);
break;
case TEX_VD_TRICUBIC_CATROM:
case TEX_VD_TRICUBIC_BSPLINE:
texres->tin = voxel_sample_tricubic(vd->dataset, vd->resol, co, (vd->interp_type == TEX_VD_TRICUBIC_BSPLINE));
break;
}
texres->tin *= vd->int_multiplier;
BRICONT;
texres->tr = texres->tin;
texres->tg = texres->tin;
texres->tb = texres->tin;
texres->ta = texres->tin;
BRICONTRGB;
return retval;
}