glTF 0.8 to 1.0 Guide

[pjcozzi]

To help 0.8 users upgrade.

I can write it.

[pjcozzi]

Notes in progress (CC @tfili, CesiumGS/cesium#3034)

• material/technique simplifications, Update material and technique schema #419
• node.rotation is now a unit quaternion (x, y, z, w), Animation: quaternion vs. axis-angle #144
  • When it is targeted for animation, spherical linear interpolation (slerp) should be used, Animation: sampler.interpolation values #156
• node.instanceSkin was removed. Its properties are now directly on node, meshes vs instanceSkin #255
• mesh.primitive.primitive -> mesh.primitive.mode, Rename primitive in mesh/primitive to mode #341
• mesh.primitive.indices are now optional, Add indices #60
• technique.parameter.source -> technique.parameter.node (in 0.8 schema, but not converter), Technique parameter questions #239
• allExtensions -> extensionsUsed, Process for adding and promoting glTF extensions #404
• asset.profile (string) to asset.profile (object) with api and version string properties, we should split API and version in profile #325
• Extensions: CESIUM_binary_glTF -> KHR_binary_glTF, [binary_glTF] First Version #400, Rename EXT_binary_glTF to KHR_binary_glTF #413

[pjcozzi]

@tfili as of the changes we've made so far for 1.0 in COLLADA2GLTF and Cesium, is there anything missing above?

[tfili]

@pjcozzi I think that is everything.

[pjcozzi]

@tfili is there anything else in the dev-0.9 branch that you want to merge into dev-1.0? Let me know when we can delete dev-0.9.

[pjcozzi]

Added the guide to the wiki: https://github.com/KhronosGroup/glTF/wiki/glTF-0.8-to-1.0-Guide

[pjcozzi]

@tfili last call for anything in the dev-0.9 branch - do you need anything before I delete it?

[tfili]

There are a bunch of string -> constant changes. Not a big deal. The only other thing is quaternion stuff which I've already implemented.