[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:

> 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.

I don't think there is a way to do that for the normalized formats
because glGetTexImage is actually implemented using a render via the
Mesa meta code so it's effectively always decompressed using a render.

For the half-float modes it would work to use glGetTexImage to invoke
the software decompressor because for some reason the meta code disables
itself for non-normalized formats. However it's probably not very good
to rely on this because we should really fix the meta code path to work
for non-normalized formats too.

- Neil