* First commit merging 2.4-based sim_physics in to volume25 branch.

Integration is still very rough around the edges and WIP, but it works, and can render smoke (using new Smoke format in Voxel Data texture) --> http://vimeo.com/6030983

More to come, but this makes things much easier to work on for me :)

source/blender/render/extern/include/RE_shader_ext.h

@@ -113,7 +113,7 @@ typedef struct ShadeInput
 	
 	/* internal face coordinates */
 	float u, v, dx_u, dx_v, dy_u, dy_v;
-	float co[3], view[3];
+	float co[3], view[3], camera_co[3];
 	
 	/* copy from material, keep synced so we can do memcopy */
 	/* current size: 23*4 */
@@ -161,6 +161,7 @@ typedef struct ShadeInput
 	
 	int samplenr;			/* sample counter, to detect if we should do shadow again */
 	int depth;				/* 1 or larger on raytrace shading */
+	int volume_depth;		/* number of intersections through volumes */
 	
 	/* stored copy of original face normal (facenor) 
 	 * before flipping. Used in Front/back output on geometry node */