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Having looked at Skia against a lot of different OS/GPU/driver combinations, I would be surprised to see bit identical results from GPU rendering except perhaps across different nvidia cards. I wouldn't even necessarily expect identical results in replicated runs on the same machine.

Worth keeping in mind that what Skia's GPU backend decides to do depends on GPU features, and sometimes on GPU workarounds. There's no guaranteed way to force it to render identically on all platforms short of something like swiftshader.



hey thanks for answering! You're one of the main skia contributor right?

I thought GrGlCaps was supposed to fallback most of the time to equivalents. Also thought that golden images baseline where pixel tested against a large set of different hardware.

But yeah, Skia blacklists MSAA for Intel GPU, so if you opt-in for sampling, you're not guaranted it's going to be enabled and therefore observe differences


Can you force CPU only and control MSAA or are you always restricted by the hardware of the host system in some ways?


you can force CPU only and also disable MSAA on the GPU renderer. Enabling the GPU renderer doesn't guarantee that everything will be generated on the GPU. Skia can still decide to rasterize a path on the CPU before uploading it on the GPU.


But if you force CPU everything should be on CPU? or do things get offloaded the developer doesn't know about?


If you use the Software renderer, then yes, it's fully rasterized on the CPU. You can even build skia without any on the GPU source code.




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