I believe the solution to my problem is
to write my own texture mappping routines, but I hope someone can tell me I am wrong.
I have a materials editor that has a list of loaded materials and used textures.
I want to display the texture maps in the viewport. The effect I want is alpha blending of the texture in decal mode with the object’s color. To my knowledge this would require me to have a separate texture for each object, because while textures may be common to objects, their transparency may differ by material. Is there a way to get this effect by explicitly setting a blend
factor instead of packing the texture with
a constant alpha value?