Various fixes for wide color gamut rendering
This CL addresses multiple issues:
- A logic issue where the wide gamut color mode was not set at the right time
- The presence of scRGB surfaces was not detected
- The sRGB to Display P3 matrix was transposed
- The color matrix was applied in gamma space instead of linear space*
- The GPU code path was doing a division by w for each pixel when a
color transform is set, which shouldn't be necessary (the code now
checks that the matrix has the expected form)
- Incorrect comment
- Dead code in Description.cpp (mDirtyUniforms was never used)
- Screenshots were taken using the last render engine configuration,
the configuration is now properly set every time
* This can in theory cause a discrepancy when we switch to/from hardware
composer mode. I was not able to create a visible discrepancy in practice
using Night Light, color blindness compensation modes and color inversion.
More importantly, how/where the hardware composer applies the color
transform is not specified: it could be gamma or linear space, before or
after the hardware color LUT. We'll address this in a future CL if needed.
In addition, this code assumes that fp16 surfaces are encoded in non-linear
space (scRGB-nl instead of scRGB) but we do not have EGL/Vulkan extensions
to specify this behavior. We need to address this as well
This CL also fixes potential divides by 0 in the GPU code path.
Bug: 29940137
Test: CtsUiRenderingTestsCases, CtsGraphicsTestCases
Change-Id: I9ae15850f8b9d48c39ebc2724ca3da202be9b008
diff --git a/services/surfaceflinger/RenderEngine/GLES20RenderEngine.cpp b/services/surfaceflinger/RenderEngine/GLES20RenderEngine.cpp
index a1ee294..37a530b 100644
--- a/services/surfaceflinger/RenderEngine/GLES20RenderEngine.cpp
+++ b/services/surfaceflinger/RenderEngine/GLES20RenderEngine.cpp
@@ -139,11 +139,10 @@
// Display-P3 only.
mat3 srgbToP3 = ColorSpaceConnector(ColorSpace::sRGB(), ColorSpace::DisplayP3()).getTransform();
- // color transform needs to be transposed and expanded to 4x4
- // to be what the shader wants
+ // color transform needs to be expanded to 4x4 to be what the shader wants
// mat has an initializer that expands mat3 to mat4, but
// not an assignment operator
- mat4 gamutTransform(transpose(srgbToP3));
+ mat4 gamutTransform(srgbToP3);
mSrgbToDisplayP3 = gamutTransform;
}
#endif
@@ -386,6 +385,7 @@
Description wideColorState = mState;
if (mDataSpace != HAL_DATASPACE_DISPLAY_P3) {
wideColorState.setColorMatrix(mState.getColorMatrix() * mSrgbToDisplayP3);
+ wideColorState.setWideGamut(true);
ALOGV("drawMesh: gamut transform applied");
}
ProgramCache::getInstance().useProgram(wideColorState);