[cairo] Re: Xgl server

[Luca Barbieri]

Another way to approach this could be to eliminate overlap geometrically 
and then directly use OpenGL polygon smoothing.

If done over the whole scene (using a retained-mode layer), this will
give mathematically perfect results (subject to numerical precision and
accuracy of texture filtering and shading) and is probably the only way
to do so.
.
It should be faster in some cases (e.g. the same large opaque primitive
repeated a lot times) but slower in others (e.g. drawing all even
horizontal lines with 1 x screen_size quads and then all even vertical
ones).