On Tue, Aug 21, 2012 at 5:57 PM, Matt Turner <[email protected]> wrote: > On Tue, Aug 21, 2012 at 4:32 PM, Anuj Phogat <[email protected]> wrote: >> Draw and probe a QUAD (in place of a LINE) in case of GL_TEXTURE_1D. This >> fixes the test failures on NVIDIA's proprietary linux drivers. In case of >> LINE, glReadPixels() misses the relevant pixels by one pixel on NVIDIA. >> >> Signed-off-by: Anuj Phogat <[email protected]> >> --- >> Brian, both these patches (including the one I sent earlier today) resolve >> separate issues. So, I'm keeping this fix in a separate patch. Let me know >> if you have any comments on the patches. >> >> tests/texturing/copyteximage.c | 16 +++++----------- >> 1 files changed, 5 insertions(+), 11 deletions(-) > > I've only been following this casually, but does this cover up a test > failure on NVIDIA? They've got a bug -- right? I don't understand why > we'd want to modify the test so that it misses the driver bug.
I don't think this is a driver bug. NVIDIA's GPU might be using a different line rasterization algorithm which generates slightly different fragments as compared to intel's GPU. OpenGL 3.0 specification, section 3.5.1 says: "Because the initial and final conditions of the diamond-exit rule may be difficult to implement, other line segment rasterization algorithms are allowed, subject to the following rules: 1. The coordinates of a fragment produced by the algorithm may not deviate by more than one unit in either x or y window coordinates from a corresponding fragment produced by the diamond-exit rule." This might or might not be the case with NVIDIA's driver. _______________________________________________ Piglit mailing list [email protected] http://lists.freedesktop.org/mailman/listinfo/piglit
