[Piglit] [PATCH piglit] Add a test case for all of the modes of BPTC texture compression

[Neil Roberts]

Ilia Mirkin <imirkin at alum.mit.edu> writes:

> I may be misunderstanding, but it seems like this test only tests the
> RGBA_UNORM format. How hard would it be to test all 4 formats? If it's
> a pain to do so in the way you're doing here, you could have a more
> basic test that just ensures that a texture that was compressed by the
> library can be used for texturing (and returns the data you'd expect
> it to).

Yes, it only tests the decompressor for one of the normalized formats. I
should have made that more clear in the commit message and in the
comment in the source code. You're right there needs to be a bunch more
tests to test the half-float formats and the compressor.

It might be a bit tricky to check that you get the data you expect from
the compressor because we would want quite a lot of leeway for the
compressor to give an estimation of the image. Maybe it would be enough
to just compress some simple images that don't have more than two
colours per block because these should probably compress quite reliably.

NVidia has a nice test image that is supposed to exercise all of the
code paths through the decompressor. I'm not exactly sure what the
license for it is but potentially we could just copy the image into
Piglit and verify that it decompresses properly.

https://code.google.com/p/nvidia-texture-tools/downloads/detail?name=bc6h_export.zip&can=2&q=

- Neil