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Post #2374295

2026-04-30 17:44 UTC

@zeux@mastodon.gamedev.place Why is every production render in existence throwing away bitangents and breaking bump-mapping on UV skewing, instead of throwing away NORMAL and reconstructing THAT? It's the one that's actually mathematically supposed to be perpendicular to the other two.

Replies (1)

  • @zeux@mastodon.gamedev.place 2026-04-30 17:57

    @nothings@mastodon.gamedev.place Interesting question! I'm not entirely sure :) This would run into problems in UV-degenerate regions but you could solve them with a synthetic orthogonal basis. Ofc none of the techniques I describe further in the post would apply to non-orthogonal bases. I'd guess the industry just gave up on skewed mapping. There's extra complications wrt TBN in that you might need a matrix *inverse* instead of just transpose in certain parts of the pipeline. And vertex averaging muddles it anyway.

    Open ##2374296