Hi, I have a simple (to describe) problem: when i use alpha-blending on two polygons that are sharing an edge (such as additive blending), the edge is processed twice (making it appear twice brigher). Strangely, i didn''t have the problem with an older driver, and my code hasn''t changed a lot. I don''t have the problem with normal polygons (only blended, since i must use the GL_LEQUAL depth test). I''m wondering how to fix the problem.. can''t i tell OpenGL not to draw the last right or bottom pixels of a polygon when it''s filled ? Y.