[Radiance-general] Slow rendering with transparant textures

[Lars O. Grobe]

> Do you mean hard-coded in Radiance here? Such a feature makes sense to 
> me also.
> In my case the mixfunc for transparancy is consuming lots of rendering 
> time. Although .cal files makes the whole system very flexible, some 
> features are so commonly used that of course it would be great if 
> these were optimized a bit. At the other hand I imagine that these 
> kind of changes are not that easily done, if it is possible at all, in 
> the first place.

The problem is that while adding such modifiers should be rather easy, 
they would break consistency in a couple of places. E.g. imagine a scene 
using a colorpict_xz modifier. Everything would be fine - until you run 
xform to rotate the scene. Xform would have to replace the optimized 
modifier now. And having two ways to do the same is always a mess to 
support. So I guess the rather few cases where this is needed do not 
rectify the trouble one would introduce in that case.

CU Lars.