[Piglit] [PATCH] primitive-restart: test primitive-restart with VBO

Jordan Justen jljusten at gmail.com
Thu May 10 08:58:45 PDT 2012

On Thu, May 10, 2012 at 7:10 AM, Brian Paul <brianp at vmware.com> wrote:
> 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
>> appreciated.
> 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.

Sure. Can you provide your Signed-off-by for the patch?

> 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?

Sure. Something like tests/spec/arb_vertex_buffer_object/combined-vbo.c?

> 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.

Okay, I'll add this.


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