gltforge

Spec-compliant, extension-first glTF 2.0 for Rust

gltforge is a glTF 2.0 toolkit built around a single principle: extensions are first-class citizens, not afterthoughts. Every intermediate stage of parsing, validation, and processing is owned by the caller — nothing is hidden.

• Extension-first — typed extension registration, import and export treated equally
• Open by design — every intermediate representation is public and caller-owned
• Spec-compliant — extensionsRequired enforced as hard errors, not warnings

Workspace

Usage

[dependencies]

gltforge = "0.0.4"

use std::path::Path;
use gltforge::parser;

// Parse a .gltf file
let json = std::fs::read_to_string("model.gltf")?;
let gltf = parser::parse(&json)?;
let buffers = parser::load_buffers(&gltf, Path::new("."))?;

// Or parse a self-contained .glb file
let data = std::fs::read("model.glb")?;
let (gltf, buffers) = parser::parse_glb(&data)?;

// Resolve an accessor to raw bytes
let accessors = gltf.accessors.as_deref().unwrap_or(&[]);
let buffer_views = gltf.buffer_views.as_deref().unwrap_or(&[]);
let bytes = parser::resolve_accessor(&accessors[0], buffer_views, &buffers)?;

CLI

cargo install gltforge-cli


# Summary (works with .gltf and .glb)

gltforge inspect model.glb


# With node hierarchy and mesh details

gltforge inspect model.gltf --nodes --mesh


# Dump raw POSITION vertices for mesh 0 (glTF coordinate space)

gltforge inspect model.gltf --dump-verts 0

glTF 2.0
generator: Khronos Blender glTF 2.0 exporter
scenes:      1
nodes:       22
meshes:      1
accessors:   83
buffer views:8
buffers:     1
materials:   1
textures:    1
animations:  1
skins:       1

node 0: Z_UP
  matrix:
    [  1.0000    0.0000    0.0000    0.0000]
    [  0.0000    0.0000    1.0000    0.0000]
    [  0.0000   -1.0000    0.0000    0.0000]
    [  0.0000    0.0000    0.0000    1.0000]
  node 1: Armature
    node 3: Skeleton_torso_joint_1
      translation: [0.0000, 0.0050, 0.6790]
      rotation:    [0.0000, -0.0378, 0.0000, -0.9993]  (xyzw)
      scale:       [1.0000, 1.0000, 1.0000]

mesh 0: Cesium_Man
  primitive 0  [TRIANGLES]
    indices:  accessor 0    SCALAR  UNSIGNED_SHORT  14016
    JOINTS_0  accessor 1    VEC4    UNSIGNED_SHORT  3273
    NORMAL    accessor 2    VEC3    FLOAT           3273
    POSITION  accessor 3    VEC3    FLOAT           3273
    TEXCOORD_0 accessor 4   VEC2    FLOAT           3273
    WEIGHTS_0 accessor 5    VEC4    FLOAT           3273

Unity

gltforge-unity compiles to a native plugin (gltforge_unity.dll) and exposes a P/Invoke API. A ScriptedImporter lets you drag .gltf and .glb files directly into the Unity project panel.

The importer builds the full scene graph as a prefab hierarchy, with mesh geometry, materials, and transforms ready to use. Coordinates are converted from glTF's right-handed system to Unity's left-handed system (X negated, winding reversed). Index format (UInt16/UInt32) is selected automatically based on vertex count.

What's imported today:

Roadmap

• glTF 2.0 schema types
• JSON parser + buffer loading
• GLB binary container parsing
• Accessor resolution
• CLI inspector (--nodes, --mesh, --dump-verts)
• Unity P/Invoke bindings — scene graph, node transforms, meshes, normals, tangents, UVs, sub-meshes
• Coordinate system conversion (glTF right-handed → Unity left-handed)
• Materials and textures (PBR Metallic Roughness)
• Skinning (JOINTS_0 / WEIGHTS_0) and animations
• Extension registry + typed dispatch
• KHR_draco_mesh_compression
• EXT_meshopt_compression
• PyO3 / Blender addon
• WASM bindings

License

MIT — see LICENSE