glTF Export Phase 2

[atteneder]

glTF Export has landed in 4.4.0. Now it's time get it out of experimental

TODO

• Run-time export via API
  • Save to file
  • Save to stream
• Interfaces
  • Editor context menu export of scene/objects
• Documentation
• Optimize output for size
  • node transform (skip default values)
  • Skip properties technically not required (like names)
  • (Option for) Minimized JSON
  • Precision rounding (e.g. 0.2 instead of 0.199999993)
• Buffer layout
  • Separate (non-interleaved; required for meshopt and 2019 LTS support)
• Materials
  • Shaders
    • BiRP Specular-Glossiness
    • URP Lit
    • URP Unlit
    • HDRP Lit
    • HDRP Unlit
  • Textures
    • Samplers
      • fix redundant glTF textures
    • Occlusion (ORM swizzle)
    • Emissive
    • MetallicRoughness (ORM swizzle)
• Tests
  • ~80% code coverage
  • Validator Integration
• Skinning (weights and joints)
• Morph targets
• Animation
• Expose Export Settings
  • Texture compression (Auto/Always PNG)
  • Jpeg compression level
  • Separate .gltf/.bin or Binary
  • Active in hierarchy only

Long-Term Features

• Async export
• Mesh quantization
• Sparse accessors
• GPU instancing
• Buffer layout
  • (Ideal) Unity layout
• Compression
  • Draco mesh-level compression
  • meshopt bufferview-level compression
  • KTX2/BasisU texture compression
• Custom data in extras property
• XMP meta data
• Materials
  • TransmissionFactor/Texture
  • Clear coat
  • Specular
  • Sheen
  • Volume
  • IOR
  • Specular/Glossiness workflow
  • Variants
• Punctual lights
• Camera
• DOTS export entity hierarchies

[ROBYER1]

Should I make an extra issue about GPU Instancing support? I want to use instanced meshes with an imported GLTF to save on file sizes.

[atteneder]

Should I make an extra issue about GPU Instancing support? I want to use instanced meshes with an imported GLTF to save on file sizes.

So you want the glTFast export to recognize Renderers with identical Meshes/Materials, so that it not only re-uses the Mesh, but adds a EXT_mesh_gpu_instancing extension, minimizing the instance overhead, right?

Yes, I'd suggest to make a dedicated issue, if it is of importance to you.

[ROBYER1]

Yes, I'd suggest to make a dedicated issue, if it is of importance to you.

I've set one up here #461