[Piglit] [PATCH] primitive-restart: test primitive-restart with VBO
brianp at vmware.com
Thu May 10 07:10:22 PDT 2012
On 05/09/2012 05:56 PM, Jordan Justen wrote:
> One additional note:
> This test passed with NVidia's driver, but failed with llvmpipe.
> I'm not certain if the test or llvmpipe is to blame. So, feedback
> either pointing out a test flaw, or known issue with llvmpipe would be
It looks like you've exposed a new bug with VBOs. You're storing both
the vertex arrays and vertex indexes in a single VBO (which is a
little unusual). Looks like something in Gallium is choking on that.
I modified your code to use separate VBOs for vertex data and indexes
and then the test passes with softpipe/llvmpipe. Perhaps you can roll
the attached patch into your change.
I'd like to have a separate test to check the case of one VBO
containing both vertex data and index data. Would you be interested
in writing such a test?
Also, the primitive-restart test could be improved in another way.
After drawing the test pattern, we should probe pixel (0,0) to check
that it's black. As it turns out, when there are primitive restart
failures/bugs, we often get a bogus vertex at (0,0) and the
triangles/lines are distorted/stretched to (0,0). When I was
debugging the llvmpipe failure I noticed that one of the line strip
tests was passing the test, but was in fact drawn incorrectly.
Probing (0,0) would have caught the false positive.
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