Carlos Garnacho authored Mar 09, 2018 and Florian Müllner committed Mar 21, 2018

By the looks of it, commit 95e9fa10 was taping over an Intel DRI bug
that would make it return post-swizzling pixel data on glReadPixels().
There's been reports over time of that commit resulting in wrong colors
on other drivers, and lately Mesa >17.3 started showing the same symptoms
on Intel.

But texture swizzling works by changing parameters before fragment shaders
and reading pixels from an already drawn FBO/texture doesn't involve those.
This should thus use pixel_format_to_gl_with_target(), which will result in
correctly requesting the same pixel format than the underlying texture,
while still considering it BGRA for the upper layers in the swizzling case.

GNOME/mutter#72

Closes: #72