[Impeller] implemented golden image tests for opengles

[gaaclarke]

fixes flutter/flutter#142354

This sets up impeller_golden_tests to run with ANGLE.

Pre-launch Checklist

• I read the Contributor Guide and followed the process outlined there for submitting PRs.
• I read the Tree Hygiene wiki page, which explains my responsibilities.
• I read and followed the Flutter Style Guide and the C++, Objective-C, Java style guides.
• I listed at least one issue that this PR fixes in the description above.
• I added new tests to check the change I am making or feature I am adding, or the PR is test-exempt. See testing the engine for instructions on writing and running engine tests.
• I updated/added relevant documentation (doc comments with ///).
• I signed the CLA.
• All existing and new tests are passing.

If you need help, consider asking for advice on the #hackers-new channel on Discord.

[gaaclarke]

This fails now currently when shaders are attempted to be compiled because they are being compiled for OpenGL, not opengles. They have #version 120 in them, not #version 100.

[gaaclarke]

This fails now currently when shaders are attempted to be compiled because they are being compiled for OpenGL, not opengles. They have #version 120 in them, not #version 100.

Fixed with impellerc flags.

[gaaclarke]

@jonahwilliams I added the flip in on the CPU side that respects Texture::GetYCoordScale. Thanks for pointing that out. I briefly looked into doing the flip on the GPU but it was more involved. We can do that later.

[jonahwilliams]

Thanks! it looks like there is a remaining color format issue BGRA vs RGBA?

[gaaclarke]

Thanks! it looks like there is a remaining color format issue BGRA vs RGBA?

Yep, looks like it. Is there something in Texture I can used to decide that? Maybe the TextureDescriptor?

[gaaclarke]

The conventional wisdom has been that BGRA is faster on some hardware. We should look to make sure we are taking advantage of that in our renderers.

[gaaclarke]

Thanks! it looks like there is a remaining color format issue BGRA vs RGBA?

Yep, looks like it. Is there something in Texture I can used to decide that? Maybe the TextureDescriptor?

Yep, the texture descriptor format has the info we want.

The conventional wisdom has been that BGRA is faster on some hardware. We should look to make sure we are taking advantage of that in our renderers.

OpenGLES is the one using RGBA, we should fix that.

[gaaclarke]

Thanks! it looks like there is a remaining color format issue BGRA vs RGBA?

Done.

[gaaclarke]

The conventional wisdom has been that BGRA is faster on some hardware. We should look to make sure we are taking advantage of that in our renderers.

I've looked into this a bit. For Android RGBA may be better. It's not clear there is a need to change this considering who is using OpenGLES.

[flutter-dashboard]

Golden file changes are available for triage from new commit, Click here to view.

Changes reported for pull request #50146 at sha 327502b

[jonahwilliams]

LGTM

It looks like there are a number of goldens on page 3-4 that aren't showing up at all, you should file a tracking issue to investigate if that is specific to the golden harness.

[gaaclarke]

Here are the ones that rendered nothing.

impeller_Play_AiksTest_CanRenderClippedLayers_OpenGLES
impeller_Play_AiksTest_ClippedBlurFilterRendersCorrectly_OpenGLES
impeller_Play_AiksTest_GaussianBlurOneDimension_OpenGLES
impeller_Play_AiksTest_CanRenderBackdropBlurHugeSigma_OpenGLES
impeller_Play_AiksTest_CanDrawPaintMultipleTimes_OpenGLES
impeller_Play_AiksTest_CanDrawPaint_OpenGLES
impeller_Play_AiksTest_CanRenderColorFilterWithInvertColorsDrawPaint_OpenGLES
impeller_Play_AiksTest_GaussianBlurRotatedAndClipped_OpenGLES
impeller_Play_AiksTest_ImageFilteredUnboundedSaveLayerWithUnboundedContents_OpenGLES
impeller_Play_AiksTest_CanDrawPaintWithAdvancedBlend_OpenGLES
impeller_Play_AiksTest_SubpassWithClearColorOptimization_OpenGLES
impeller_Play_AiksTest_CanRenderClippedBlur_OpenGLES
impeller_Play_AiksTest_DrawScaledTextWithPerspectiveNoSaveLayer_OpenGLES
impeller_Play_AiksTest_CanRenderLinearGradientMaskBlur_OpenGLES
impeller_Play_AiksTest_GaussianBlurScaledAndClipped_OpenGLES
impeller_Play_AiksTest_CollapsedDrawPaintInSubpass_OpenGLES

I suspect the blur ones are probably covered under flutter/flutter#142355. I'll double check these against Metal since drawing nothing may be the correct behavior in some cases.

Note: I'm going to land the update of the TODO(tbd) in a separate PR because of the overhead of running CI.

[jonahwilliams]

SGTM