[TODO] Colorspace support

[syoyo]

This feature is related to MatrialX support

https://github.com/PixarAnimationStudios/USD/issues/1523

Status

• [x] Parsing 'colorSpace' metadataum https://github.com/syoyo/tinyusdz/commit/8dce7bc170b466291f070884e53f8bee3c6e093a
• Colorspace support in Tydra
  • [x] Colorspace conversion
  • [x] Setup texture info with colorSpace https://github.com/syoyo/tinyusdz/commit/61fb00604985596a9e0c1c5bce138c4a8110b6c3
  • [ ] OCIO lut support

Mandatory.

This will be provided as a built-in colorspace

• srgb_texture
• lin_rec709
• srgb_displayp3 https://www.wwdcnotes.com/notes/wwdc23/10086/

Others

ocio colorspace will be provided only by SPI1D or SPI3D LUT through TinyColorIO https://github.com/syoyo/tinycolorio

Physical unit

This relates to spectral color support in USD https://github.com/syoyo/tinyusdz/issues/57

• irradiance, candela(for texel value)

Colorspace conversion implementation status

Implementation is located in Tydra and image-utils.cc https://github.com/syoyo/tinyusdz/blob/dev/src/image-util.hh

• [x] sRGB <-> Linear
• [x] Rec709 <-> Linear
• [ ] OCIO