Hi,
I don’t understand very well how GL_PATCH and the primitive generator are supposed to work.
I am currently manipulating GL_PATCH primitives with 3 vertices. I basically have 1 origin vertex, 1 U-axis vertex and 1 V-axis vertex.
My patches are entirely generated off uniform values, that is, patch vertices are not even used. So I don’t need any actual patch vertex at all. 1 would be sufficient as I need to “declare” the GL_PATCH primitive.
Problem: when I try to only have 1 patch vertex, my code doesn’t work. I can’t understand why, conceptually speaking.
The primitive generator doesn’t use patch vertices, right? I mean, it just generates U,V parametric values (all sitting between 0.0 and 1.0) and calls the evaluation shader with them, right?
Patch vertices are just there for my own convenience, or am I missing something?
Cheers,
Fred