My friend just asked me this. He has a triangle and distinct color at each vertices.
Now I know, if we specify color at each vertex, openGL does a gourad interpolation and fills the whole triangle accordingly. He also has a transparency value at each vertex. Now how is it possible to render the triangle using the transparency values at each vertex such that at any point inside the triangle the transparency is based on the three values like it does with the color. I am wondering, if we specify RGBA in the color field for each vertex, would openGL interpolate the alpha channel too ??
Or do I find out the Alpha at any point using barycentric co-ordinates but then how do I tell openGL to do the blend in absence of a texture ???
[This message has been edited by bivasb (edited 04-09-2001).]