Revision: 23563
          
http://projects.blender.org/plugins/scmsvn/viewcvs.php?view=rev&root=bf-blender&revision=23563
Author:   broken
Date:     2009-09-30 00:01:32 +0200 (Wed, 30 Sep 2009)

Log Message:
-----------
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has been removed and has been replaced by a 'transmission colour' - controlling 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...

Modified Paths:
--------------
    trunk/blender/release/scripts/ui/buttons_material.py
    trunk/blender/release/scripts/ui/buttons_texture.py
    trunk/blender/source/blender/blenkernel/intern/material.c
    trunk/blender/source/blender/blenkernel/intern/texture.c
    trunk/blender/source/blender/blenloader/intern/readfile.c
    trunk/blender/source/blender/editors/render/render_preview.c
    trunk/blender/source/blender/makesdna/DNA_material_types.h
    trunk/blender/source/blender/makesdna/DNA_texture_types.h
    trunk/blender/source/blender/makesrna/intern/rna_material.c
    trunk/blender/source/blender/makesrna/intern/rna_texture.c
    trunk/blender/source/blender/render/intern/include/volume_precache.h
    trunk/blender/source/blender/render/intern/include/volumetric.h
    trunk/blender/source/blender/render/intern/source/convertblender.c
    trunk/blender/source/blender/render/intern/source/rayshade.c
    trunk/blender/source/blender/render/intern/source/texture.c
    trunk/blender/source/blender/render/intern/source/volume_precache.c
    trunk/blender/source/blender/render/intern/source/volumetric.c
    trunk/blender/source/blender/render/intern/source/voxeldata.c

Modified: trunk/blender/release/scripts/ui/buttons_material.py
===================================================================
--- trunk/blender/release/scripts/ui/buttons_material.py        2009-09-29 
21:42:40 UTC (rev 23562)
+++ trunk/blender/release/scripts/ui/buttons_material.py        2009-09-29 
22:01:32 UTC (rev 23563)
@@ -609,7 +609,24 @@
                mat = context.material
                engine = context.scene.render_data.engine
                return mat and (mat.type == 'VOLUME') and (engine in 
self.COMPAT_ENGINES)
+
+class MATERIAL_PT_volume_density(VolumeButtonsPanel):
+       __label__ = "Density"
+       __default_closed__ = False
+       COMPAT_ENGINES = set(['BLENDER_RENDER'])
+
+       def draw(self, context):
+               layout = self.layout
+
+               mat = context.material
+               vol = context.material.volume
                
+               split = layout.split()
+               row = split.row()
+               row.itemR(vol, "density")
+               row.itemR(vol, "density_scale")
+
+               
 class MATERIAL_PT_volume_shading(VolumeButtonsPanel):
        __label__ = "Shading"
        __default_closed__ = False
@@ -620,22 +637,23 @@
 
                vol = context.material.volume
                
-               row = layout.row()
-               row.itemR(vol, "density")
-               row.itemR(vol, "scattering")
-
                split = layout.split()
                
                col = split.column()
-               col.itemR(vol, "absorption")
-               col.itemR(vol, "absorption_color", text="")
-
+               col.itemR(vol, "scattering")
+               col.itemR(vol, "asymmetry")
+               col.itemR(vol, "transmission_color")
+               
                col = split.column()
-               col.itemR(vol, "emission")
-               col.itemR(vol, "emission_color", text="")
+               sub = col.column(align=True)
+               sub.itemR(vol, "emission")
+               sub.itemR(vol, "emission_color", text="")
+               sub = col.column(align=True)
+               sub.itemR(vol, "reflection")
+               sub.itemR(vol, "reflection_color", text="")     
 
-class MATERIAL_PT_volume_scattering(VolumeButtonsPanel):
-       __label__ = "Scattering"
+class MATERIAL_PT_volume_lighting(VolumeButtonsPanel):
+       __label__ = "Lighting"
        __default_closed__ = False
        COMPAT_ENGINES = set(['BLENDER_RENDER'])
 
@@ -648,25 +666,27 @@
                
                col = split.column()
                col.itemR(vol, "scattering_mode", text="")
+               
+               col = split.column()
+               
                if vol.scattering_mode == 'SINGLE_SCATTERING':
                        col.itemR(vol, "light_cache")
                        sub = col.column()
                        sub.active = vol.light_cache
                        sub.itemR(vol, "cache_resolution")
                elif vol.scattering_mode in ('MULTIPLE_SCATTERING', 
'SINGLE_PLUS_MULTIPLE_SCATTERING'):
+                       sub = col.column()
+                       sub.enabled = True
+                       sub.active = False
+                       sub.itemR(vol, "light_cache")
                        col.itemR(vol, "cache_resolution")
                        
                        sub = col.column(align=True)
                        sub.itemR(vol, "ms_diffusion")
                        sub.itemR(vol, "ms_spread")
                        sub.itemR(vol, "ms_intensity")
-               
-               col = split.column()
-               # col.itemL(text="Anisotropic Scattering:")
-               col.itemR(vol, "phase_function", text="")
-               if vol.phase_function in ('SCHLICK', 'HENYEY-GREENSTEIN'):
-                       col.itemR(vol, "asymmetry")
 
+
 class MATERIAL_PT_volume_transp(VolumeButtonsPanel):
        __label__= "Transparency"
        COMPAT_ENGINES = set(['BLENDER_RENDER'])
@@ -693,16 +713,15 @@
                col = split.column()
                col.itemL(text="Step Calculation:")
                col.itemR(vol, "step_calculation", text="")
-               sub = col.column(align=True)
-               sub.itemR(vol, "step_size")
-               sub.itemR(vol, "shading_step_size")
+               col = col.column(align=True)
+               col.itemR(vol, "step_size")
                
                col = split.column()
                col.itemL()
                col.itemR(vol, "depth_cutoff")
-               col.itemR(vol, "density_scale")
 
+bpy.types.register(MATERIAL_PT_volume_density)
 bpy.types.register(MATERIAL_PT_volume_shading)
-bpy.types.register(MATERIAL_PT_volume_scattering)
+bpy.types.register(MATERIAL_PT_volume_lighting)
 bpy.types.register(MATERIAL_PT_volume_transp)
 bpy.types.register(MATERIAL_PT_volume_integration)

Modified: trunk/blender/release/scripts/ui/buttons_texture.py
===================================================================
--- trunk/blender/release/scripts/ui/buttons_texture.py 2009-09-29 21:42:40 UTC 
(rev 23562)
+++ trunk/blender/release/scripts/ui/buttons_texture.py 2009-09-29 22:01:32 UTC 
(rev 23563)
@@ -246,13 +246,14 @@
                                col = split.column()
                                factor_but(col, tex.map_density, "map_density", 
"density_factor", "Density")
                                factor_but(col, tex.map_emission, 
"map_emission", "emission_factor", "Emission")
-                               factor_but(col, tex.map_absorption, 
"map_absorption", "absorption_factor", "Absorption")
                                factor_but(col, tex.map_scattering, 
"map_scattering", "scattering_factor", "Scattering")
+                               factor_but(col, tex.map_reflection, 
"map_reflection", "reflection_factor", "Reflection")
                                
                                col = split.column()
                                col.itemL(text=" ")
                                factor_but(col, tex.map_alpha, 
"map_coloremission", "coloremission_factor", "Emission Color")
-                               factor_but(col, tex.map_colorabsorption, 
"map_colorabsorption", "colorabsorption_factor", "Absorption Color")
+                               factor_but(col, tex.map_colortransmission, 
"map_colortransmission", "colortransmission_factor", "Transmission Color")
+                               factor_but(col, tex.map_colorreflection, 
"map_colorreflection", "colorreflection_factor", "Reflection Color")
 
                elif la:
                        row = layout.row()
@@ -642,6 +643,7 @@
                row.itemR(vd, "still_frame_number")
                
                layout.itemR(vd, "interpolation")
+               layout.itemR(vd, "extension")
                layout.itemR(vd, "intensity")
                
 class TEXTURE_PT_pointdensity(TextureButtonsPanel):

Modified: trunk/blender/source/blender/blenkernel/intern/material.c
===================================================================
--- trunk/blender/source/blender/blenkernel/intern/material.c   2009-09-29 
21:42:40 UTC (rev 23562)
+++ trunk/blender/source/blender/blenkernel/intern/material.c   2009-09-29 
22:01:32 UTC (rev 23563)
@@ -172,15 +172,15 @@
 
        ma->vol.density = 1.0f;
        ma->vol.emission = 0.0f;
-       ma->vol.absorption = 1.0f;
        ma->vol.scattering = 1.0f;
+       ma->vol.reflection = 1.0f;
+       ma->vol.transmission_col[0] = ma->vol.transmission_col[1] = 
ma->vol.transmission_col[2] = 1.0f;
+       ma->vol.reflection_col[0] = ma->vol.reflection_col[1] = 
ma->vol.reflection_col[2] = 1.0f;
        ma->vol.emission_col[0] = ma->vol.emission_col[1] = 
ma->vol.emission_col[2] = 1.0f;
-       ma->vol.absorption_col[0] = ma->vol.absorption_col[1] = 
ma->vol.absorption_col[2] = 0.0f;
        ma->vol.density_scale = 1.0f;
        ma->vol.depth_cutoff = 0.01f;
        ma->vol.stepsize_type = MA_VOL_STEP_RANDOMIZED;
        ma->vol.stepsize = 0.2f;
-       ma->vol.shade_stepsize = 0.2f;
        ma->vol.shade_type = MA_VOL_SHADE_SINGLE;
        ma->vol.shadeflag |= MA_VOL_PRECACHESHADING;
        ma->vol.precache_resolution = 50;

Modified: trunk/blender/source/blender/blenkernel/intern/texture.c
===================================================================
--- trunk/blender/source/blender/blenkernel/intern/texture.c    2009-09-29 
21:42:40 UTC (rev 23562)
+++ trunk/blender/source/blender/blenkernel/intern/texture.c    2009-09-29 
22:01:32 UTC (rev 23563)
@@ -984,6 +984,7 @@
        vd->interp_type= TEX_VD_LINEAR;
        vd->file_format= TEX_VD_SMOKE;
        vd->int_multiplier = 1.0;
+       vd->extend = TEX_CLIP;
        vd->object = NULL;
        
        return vd;

Modified: trunk/blender/source/blender/blenloader/intern/readfile.c
===================================================================
--- trunk/blender/source/blender/blenloader/intern/readfile.c   2009-09-29 
21:42:40 UTC (rev 23562)
+++ trunk/blender/source/blender/blenloader/intern/readfile.c   2009-09-29 
22:01:32 UTC (rev 23563)
@@ -9573,15 +9573,12 @@
                        if (ma->vol.stepsize < 0.0001f) {
                                ma->vol.density = 1.0f;
                                ma->vol.emission = 0.0f;
-                               ma->vol.absorption = 1.0f;
                                ma->vol.scattering = 1.0f;
                                ma->vol.emission_col[0] = 
ma->vol.emission_col[1] = ma->vol.emission_col[2] = 1.0f;
-                               ma->vol.absorption_col[0] = 
ma->vol.absorption_col[1] = ma->vol.absorption_col[2] = 0.0f;
                                ma->vol.density_scale = 1.0f;
                                ma->vol.depth_cutoff = 0.01f;
                                ma->vol.stepsize_type = MA_VOL_STEP_RANDOMIZED;
                                ma->vol.stepsize = 0.2f;
-                               ma->vol.shade_stepsize = 0.2f;
                                ma->vol.shade_type = MA_VOL_SHADE_SINGLE;
                                ma->vol.shadeflag |= MA_VOL_PRECACHESHADING;
                                ma->vol.precache_resolution = 50;
@@ -9703,6 +9700,8 @@
        {
                Scene *sce;
                Object *ob;
+               Material *ma;
+               Tex *tex;
 
                for(sce = main->scene.first; sce; sce = sce->id.next)
                        if(sce->unit.scale_length == 0.0f)
@@ -9716,7 +9715,21 @@
                        /* rotation modes were added, but old objects would now 
default to being 'quaternion based' */
                        ob->rotmode= ROT_MODE_EUL;
                }
+               
+               for (ma = main->mat.first; ma; ma=ma->id.next) {
+                       if (ma->vol.reflection == 0.f) {
+                               ma->vol.reflection = 1.f;
+                               ma->vol.transmission_col[0] = 
ma->vol.transmission_col[1] = ma->vol.transmission_col[2] = 1.0f;
+                               ma->vol.reflection_col[0] = 
ma->vol.reflection_col[1] = ma->vol.reflection_col[2] = 1.0f;
+                       }
+               }
 
+               for (tex = main->tex.first; tex; tex=tex->id.next) {
+                       if (tex->vd) {
+                               if (tex->vd->extend == 0) tex->vd->extend = 
TEX_CLIP;
+                       }
+               }
+               
                for(sce= main->scene.first; sce; sce= sce->id.next)
                {
                        if(sce->audio.main == 0.0)

Modified: trunk/blender/source/blender/editors/render/render_preview.c
===================================================================
--- trunk/blender/source/blender/editors/render/render_preview.c        
2009-09-29 21:42:40 UTC (rev 23562)
+++ trunk/blender/source/blender/editors/render/render_preview.c        
2009-09-29 22:01:32 UTC (rev 23563)
@@ -334,6 +334,19 @@
                                                }
                                        }
                                }
+                               
+                               /* turn off bounce lights for volume, 
+                                * doesn't make much visual difference and 
slows it down too */
+                               if(mat->material_type == MA_TYPE_VOLUME) {
+                                       for(base= sce->base.first; base; base= 
base->next) {
+                                               if(base->object->type == 
OB_LAMP) {
+                                                       /* if doesn't match 
'Lamp.002' --> main key light */
+                                                       if( 
strcmp(base->object->id.name+2, "Lamp.002") != 0 ) {
+                                                               
base->object->restrictflag |= OB_RESTRICT_RENDER;
+                                                       }
+                                               }
+                                       }
+                               }
 
                                
                                if(sp->pr_method==PR_ICON_RENDER) {
@@ -363,6 +376,8 @@
 
                                                if(matar && actcol < 
base->object->totcol)
                                                        (*matar)[actcol]= mat;
+                                       } else if (base->object->type == 
OB_LAMP) {
+                                               base->object->restrictflag &= 
~OB_RESTRICT_RENDER;
                                        }
                                }
                        }

Modified: trunk/blender/source/blender/makesdna/DNA_material_types.h
===================================================================
--- trunk/blender/source/blender/makesdna/DNA_material_types.h  2009-09-29 
21:42:40 UTC (rev 23562)
+++ trunk/blender/source/blender/makesdna/DNA_material_types.h  2009-09-29 
22:01:32 UTC (rev 23563)
@@ -50,26 +50,23 @@
 typedef struct VolumeSettings {
        float density;
        float emission;
-       float absorption;
        float scattering;
+       float reflection;
 
        float emission_col[3];

@@ Diff output truncated at 10240 characters. @@

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