[Gzz] 28th-29th (jvk)

[Janne Kujala]

28th & 29th: irregular shape work

Implemented texture shader and multitexture profiles.
Also added an option to use dot4 interpolation with
register combiners and an option to use the nearest of 
four precomputed angles with standard GL profile.

The nearest of four looks very good on nvidia, better than
interpolating between three angles. However, the low texture 
color resolution of G400 (only 4 bit alpha) makes it look
bad on anything but very small scales. Furthermore, the
texture binding cannot be changed between Begin and End.

Today: thinking about a new irregu renderable and
       a table of all the different profiles

- The renderable will have to contain many hard-coded
  parts for different profiles (multitexture on/off, 
  shader texcoords on/off, ...)

- Need a way to pass a polygon structure to the renderable.


        jvk