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authorRobert Ellison <[email protected]>2009-03-24 09:53:22 -0600
committerRobert Ellison <[email protected]>2009-03-24 10:01:23 -0600
commitcc8afbd3862fedfe42e51c3774960d1c7078ec53 (patch)
treedb20a75c4acb2b24785d5bdce953742f9e9a826e /progs/trivial/tri-z-eq.c
parent2312f697a27da366ecda9cbae9ddf8c63de910d5 (diff)
i965: fix point rasterization when rendering to FBO
The FBO pixel coordinate system, with (0,0) as the upper-left pixel, is inverted in Y compared to the normal OpenGL pixel coordinate system, which has (0,0) as its lower-left pixel. Viewport and polygon stipple are sensitive to this inversion; so is point rasterization. The basic fix is simple: when rendering to an FBO, instead of the normal RASTRULE_UPPER_RIGHT that's appropriate for OpenGL windows, use the Y inversion RASTRULE_LOWER_RIGHT. Unfortunately, current Intel documentation has this value listed as "Reserved, but not seen as useful". It does work on at least some i965-class devices, though; and the worst that could happen if an older device didn't support it would be incorrect point rasterization to FBOs, which is what happens already, so this fix is at least no worse than what happens presently, and is better for some (and possibly all) i965-class devices.
Diffstat (limited to 'progs/trivial/tri-z-eq.c')
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