[Piglit] Default window sizes and NPOT

[Brian Paul]

On 08/15/2014 08:52 AM, Ilia Mirkin wrote:
> Brian,
>
> You recently went on a campaign against setting .window_width/height
> in piglit tests, in order to fix issues on Windows I guess? I noticed
> that a bunch of failures on a NV17 card (GeForce4 MX 440) are due to
> the fact that the window sizes are now 160x160 (NPOT) and the tests
> use that in order to size their textures.
>
> What is the proper way to resolve this? Temporarily I've changed the
> default window width/height to 128, but that's not going to work more
> generally for the same reason you increased it to 160x160. Should I
> just do so on tests I identify as runnable on nouveau_vieux and that
> also have this issue? Perhaps increase to 256x256? Something else?
>
> You can find such tests with
>
> git grep -C2 piglit_width tests/fbo | grep glTexImage
>
> Not all of them run on nouveau_vieux, but some do.
>
> Thanks for any advice,

If a test like fbo-alphatest-formats.c creates a texture equal in size 
to the window and the window size is not explicit and the test doesn't 
check if NPOT textures are supported, I'd say the test is broken.  I 
didn't see any regressions when I removed the original window size 
because llvmpipe and more recent nvidia hardware support NPOT textures.

For these tests, the simplest thing is probably just setting the window 
size to 256x256.  Otherwise, we should probably create the texture with 
an explicit POT size and check that the window is at least that size 
before probing.  See sample patch attached.

-Brian


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