GltfReader

Parses a glTF 2.0 JSON document + optional BIN buffer into a GltfModel suitable for driving textured + lit mesh draws. Built for the b3dm / i3dm / cmpt content paths plus the 3D Tiles 1.1 3DTILES_content_gltf extension; reads enough of the spec for photogrammetry-style assets and ignores features the renderer doesn't yet consume (skinning, morph targets, animations, KHR_draco compression, KTX2 textures).

Distinct from the older GltfLoader which is wired to the tutorial's single-asset GltfScene API and supports only data-URI buffers; this reader supports the BIN-chunk pathway used by every b3dm in the wild.