[Enhancement] [Tydra] Support Vertex Animation Texture export?

[syoyo]

What is Vertex Animation Texture?

Bake the sequence of position/normal values to a texture.

https://medium.com/tech-at-wildlife-studios/texture-animation-techniques-1daecb316657

Procedure in TinyUSDZ Tydra API

• Convert mesh as usual(Tydra RenderData)
• Extract timeSample data of position and normal(and any primvars including texcoords) from USD GeomMesh Prim
• Save it to texture
  • PNG(16bit) : stb_image_write, fpng
  • EXR(fp16/fp32) : tinyexr
  • DNG/TIFF(10/12 bit int, fp16/fp32) : tinydngwriter
  • BC6H? : Currently no support in TinyUSDZ

BlendShapes?

BlendShape points/normals can also be converted to VAT. It would make BlendShape animation easier on realtime rendering engines.