Full glTF 2.0 support

[bwasty]

Tracking issue for supported features.
Bold ones are "more important" and should be implemented soon.
For details about each entity, refer to the Properties Reference of the specification.

LAST UPDATE: 2018-08-17

• Scene
  • choosing scenes
• Node
  • Transformations (matrix, TRS)
  • children
  • mesh
  • camera
    • perspective
      • finite
      • infinite
    • orthographic
    • choosing cameras (CLI param --cam-index)
  • skin
  • weights
• Mesh
  • primitives
  • weights
• Primitive
  • Attributes
    • positions, normals, tangents, 2 tex coord sets, 1 color set, joints, weights
    • all tex coord formats
    • TEX_COORD_1
    • all color formats
    • COLOR_0
    • [ ] generate missing normals and tangents (optional, since only an 'implementation note' -> Generate normals/tangents/bitangents gltf-rs/gltf#22)
  • Indices
  • No Indices (-> glDrawArrays())
  • Material
  • Mode
    • Triangles
    • Others: Points, Lines, LineLoop, LineStrip, TriangleStrip, TriangleFan
  • targets
• Material
  • pbrMetallicRoughness
    • base color (factor + texture)
    • full PBR lighting
  • normalTexture
  • occlusionTexture
  • emissiveTexture + emissiveFactor
  • alphaMode + alphaCutoff*
    (works, but not always correct - transparency/depth sorting is missing)
  • doubleSided
• Texture
  • Sampler
  • Image
  • textureInfo (texCoord set index)
• Animation
• Skin

[alteous]

FYI, here is the reference implementation.

[bwasty]

@alteous Thanks, I'm already watching it :)
Though I'll continue porting learnopengl.com anyway and start with that probably (porting is fun^^).

---

Also: updated the "Attributes" section, not quite done after all...

[bwasty]

Ticked off a few boxes and marked where sample models are missing for the remaining features.

[bwasty]

Recently ticked off: Scene (--scene parameter), camera (orthographic, infinite perspective, CLI parameters) and vertex colors (COLOR_0).

[bwasty]

Ticket off a few items (-> #51) - all that remains is related to animations.

[berkus]

Hi, what's the progress with animations support?