What kind of mask buffers are available on GL? Actually, I would be interested to do following. I want an float-variable array, size of the screen (like color buffer, depth buffer, stencil buffer ...) so, that while drawing an triangle, I could draw the texture''s alpha values to that mask-array. Then, when drawing an other triangle, I would like to use this mask-buffer as kind of alpha mask. So that the new triangle would not appear where the value of this buffer is zero, and would appear 100% where it is 1. Is this possible?