Wheee!

Initial commit for supporting rendering particles directly as 
volume density. It works by looking up how many particles are 
within a specified radius of the currently shaded point and using 
that to calculate density (which is used just as any other 
measure of density would be).

http://mke3.net/blender/devel/rendering/volumetrics/smoke_test01.mov
http://mke3.net/blender/devel/rendering/volumetrics/smoke_test01.blend

Right now it's an early implementation, just to see that it can 
work - it may end up changing quite a bit. Currently, it's just a 
single switch on the volume material - it looks up all particles 
in the scene for density at the current shaded point in world 
space (so the volume region must enclose the particles in order 
to render them.

This will probably change - one idea I have is to make the 
particle density estimation a procedural texture with options for:
* the object and particle system to use
* the origin of the co-ordinate system, i.e. object center, world 
space, etc.

This would allow you in a sense, to instance particle systems for 
render - you only need to bake one particle system, but you can 
render it anywhere.

Anyway, plenty of work to do here, firstly on getting a nice
density evaluation with falloff etc...

1 files changed, 12 insertions, 0 deletions

diff --git a/source/blender/render/intern/include/render_types.h b/source/blender/render/intern/include/render_types.h
index 1768b052b54..2db70c460f9 100644
--- a/source/blender/render/intern/include/render_types.h
+++ b/source/blender/render/intern/include/render_types.h
@@ -198,6 +198,8 @@ struct Render
 	ListBase *sss_points;
 	struct Material *sss_mat;
 
+	struct KDTree *particles_tree;
+
 	ListBase customdata_names;
 
 	struct Object *excludeob;
@@ -347,6 +349,16 @@ typedef struct HaloRen
 
 /* ------------------------------------------------------------------------- */
 
+typedef struct ParticleRen
+{
+	struct ParticleRen *next, *prev;
+	float co[3];	// location
+	// float col[3]; // colour
+	// float vec[3]; // direction
+} ParticleRen;
+
+/* ------------------------------------------------------------------------- */
+
 typedef struct StrandVert {
 	float co[3];
 	float strandco;