tree 546acf824881a4a51a01fd27836d7ece0b0efd5d
parent 1821df6cd73fd31ef0b3d0c6e8fc4219bdce2002
author Alec Mouri <alecmouri@google.com> 1654210505 +0000
committer Alec Mouri <alecmouri@google.com> 1654533633 +0000

Use the correct dataspace in shaders.cpp

This improves the quality of HDR->SDR tone-mapping in TextureView by
removing an incorrect gamut mapping which was causing undesired hue
shift.

The technical detail is that in TextureView, skia will color manage the
input image to the destination colorspace prior to tone-mapping. The
tone-mapping shader library compensates when authoring the shader to use
the correct EOTF when re-decoding the image, but did not compensate when
binding uniforms. This patch compensates accordingly so that the correct
gamut->gamut mapping is applied.

This patch adds a brief test suite for libshaders to verify that the
correct color gamut matrices are being selected.

Bug: 234355355
Test: Observe accurate HLG colors in Photos and Instagram where
TextureView is used for media playback.
Test: libshaders_test

Change-Id: I801349cfe1780880a55528fd7e91ff1ac553281b