When drawing long lines that extend well off the edge of the screen, some of these lines disappear completely instead of being clipped in the usual way. I am using a G965 with the latest git version of Mesa DRI. The problem seems to lie in the generated clip program. In the case that _both_ dot products are positive (meaning that the line should not be clipped against that particular plane), an erroneous clip is sometimes generated.
Created attachment 9518 [details] [review] Patch to correct line clipping for i965 I see some chatter about a "-ve rhw" workaround in the code that might have something to do with this bug. Regardless, the attached patch seems to work.
Created attachment 11044 [details] Test case that demonstrates the missing lines Here is a sample program that demonstrates the bug. This program draws 10 long lines at a slightly askew angle. However, only 7 lines appear on screen. If the angle of the glRotatef() command is modified slightly, all 10 lines will appear. I would be very appreciative if an engineer from Intel could try to reproduce this on their end. Thanks.
Eric, would you please review the patch?
Committed. Thanks!
Mass version move, cvs -> git
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