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Leaving No Pixel Behind: Three Years in Xenia's GPU Emulation (xenia.jp)
135 points by crummy 13 days ago | hide | past | favorite | 6 comments

This origin story of the Xenos GPU is pretty interesting:

> Information about the interface and the behavior of the Xbox 360’s GPU was obtained from publicly available sources, such as [...] the unofficial Freedreno driver (as the Adreno 200 GPU is heavily based on the Xenos)

> Contrary to a common misconception, the Xbox 360, however, is not just a “DirectX 9 box”. It essentially contains a tile-based (though not entirely — we’ll return to this later) mobile-like GPU, though with much more raw power than a comparable mobile GPU. If you compare the registers of the Xenos and the Qualcomm Adreno 200, you can see that most of them are the same, as they are almost the same GPUs — the Adreno 200 was called the AMD Z430 before having been acquired by Qualcomm, and was even referred to as the “mini-Xenos”!

Adreno is even an anagram for Radeon.

Lots of interesting details. I especially liked the section on gamma handling. I knew most of the theory there, but it was a readable refresher and seeing before/after images of emulated games really helped to make things understandable.

(Xenia is an xbox 360 emulator)

I'm surprised by how small Xenia is, 11.1MB to emulate an XBOX 360!

Phew. Those are the sort of release notes one might expect after 6 years.

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