Given the comparable performance of OpenGL and Metal on the same hardware I was under the impression that is how Apple had been implementing OpenGL for quite a while.

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my123 2 hours ago | parent [-]

OpenGL on Apple GPUs is implemented on top of Metal with some private extensions to be closer to OpenGL behaviour. Making things work performantly on top of regular Metal is quite a bit harder.

	▲	LoganDark 2 hours ago \| parent [-]
		Not sure why this is downvoted, it's true: https://rosenzweig.io/blog/asahi-gpu-part-6.html > Comparing traces, the render pass "OpenGL mode" sets an unknown bit in this kernel-processed block. If we set the same bit in our OpenGL driver, we find the clip space changes to -1/1.