[Soc-2012-dev] Weekly progress report #8 - Smoke Simulator Improvements

[Miika Hämäläinen]

> What you did this week
* I finished smoke color 3D-view preview. This was matter of adding 
support for rgba 3D-textures besides already supported intensity ones 
and rewriting the shader to process the premultiplied color data correctly.
* While experimenting with colors I noticed an unexpected issue: Smoke 
colors didn't mix up so nicely as I had hoped. It seems like different 
smoke flows just collide while mostly preserving their original color.
* I decided to add color diffusion step that would slowly mix colors 
within smoke nearby. However that slowed down the simulation a lot and 
caused some strange artifacts that I had to solve.
* Finally I noticed that color diffusion makes colors to no longer work 
for high resolution smoke. Only solution would be to do full diffusion 
step on high resolution data as well and that would slow down simulation 
significantly.
* Eventually me and Daniel decided to just skip color diffusion and go 
with not so well mixing but at least consistently working colors.
* So with all delays I now have high resolution colors and rendering 
support almost done but still have some things to do for next week. :p

> What you plan to do next week
I'm going to finish this smoke color implementation. For rest of the 
week I'm planning to do smaller tweaking, cleanup and optimization on 
smoke code and prepare couple of example .blend files so users can 
better get started with these new features.