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

[Ilia Mirkin]

On Wed, Jul 23, 2014 at 6:10 AM, Neil Roberts <neil at linux.intel.com> wrote:
> 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.

Is there a way to read back the image once it's compressed that
ensures that software would be used to unpack it? If so, just compare
that using the texture in a shader == reading it back post
compression. Anyways, however you want to test is fine with me. My
main point is that it doesn't _have_ to be some huge complex thing, as
long as there's some verification that texturing from a shader/blits
isn't totally broken. But perhaps there's no easy way to do that.

  -ilia