Less than a month ago, I began investigating the Apple M1 GPU in hopes of developing a free and open-source driver. This week, I’ve reached a second milestone: drawing a triangle with my own open-source code. The vertex and fragment shaders are handwritten in machine code, and I interface with the hardware via the IOKit kernel driver in an identical fashion to the system’s Metal userspace driver.

Dissecting the Apple M1 GPU, part I
- https://rosenzweig.io/blog/asahi-gpu-part-1.html