Add option to compress vertex normal tangent to axis angle#24535
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Add option to compress vertex normal tangent to axis angle#24535beicause wants to merge 1 commit into
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Objective
Followup to #21926. Adds option to compress vertex normal tangent into axis angle which saves 4 bytes per vertex.
Solution
Add a new
MeshAttributeCompressionFlags::PACKED_AXIS_ANGLE_TBNflag. If it's enabled and position, normal and tangent are all need to be compressed, we convert TBN to axis angle representation - octahedral encoded Snorm16x2 axis in normal location + Snorm16 angle in position.w.Compared to oct encoded normal + oct encoded tangent, byte usage is reduced by 2, but it utilizes the unused w component in compressed position so the actual reduction is 4 bytes, considering most users don't fill position.w with custom data.
Testing
I modified the
deferred_renderingexample to use axis-angle compression for the cube with parallax mapping.