CesiumGSglTF Pipeline
Content pipeline tools for optimizing glTF assets by Richard Lee and the Cesium team.
Supports common operations including:
- Converting glTF to glb (and reverse)
- Saving buffers/textures as embedded or separate files
- Converting glTF 1.0 models to glTF 2.0
- Applying Draco mesh compression
gltf-pipeline can be used as a command-line tool or Node.js module.
Getting Started
Install Node.js if you don't already have it, and then:
npm install -g gltf-pipelineUsing gltf-pipeline as a command-line tool:
Converting a glTF to glb
gltf-pipeline -i model.gltf -o model.glb
gltf-pipeline -i model.gltf -b
Converting a glb to glTF
gltf-pipeline -i model.glb -o model.gltf
gltf-pipeline -i model.glb -j
Converting a glTF to Draco glTF
gltf-pipeline -i model.gltf -o modelDraco.gltf -d
Saving separate textures
gltf-pipeline -i model.gltf -t
Using gltf-pipeline as a library:
Converting a glTF to glb:
const gltfPipeline = require("gltf-pipeline");
const fsExtra = require("fs-extra");
const gltfToGlb = gltfPipeline.gltfToGlb;
const gltf = fsExtra.readJsonSync("./input/model.gltf");
const options = { resourceDirectory: "./input/" };
gltfToGlb(gltf, options).then(function (results) {
fsExtra.writeFileSync("model.glb", results.glb);
});Converting a glb to embedded glTF
const gltfPipeline = require("gltf-pipeline");
const fsExtra = require("fs-extra");
const glbToGltf = gltfPipeline.glbToGltf;
const glb = fsExtra.readFileSync("model.glb");
glbToGltf(glb).then(function (results) {
fsExtra.writeJsonSync("model.gltf", results.gltf);
});Converting a glTF to Draco glTF
const gltfPipeline = require("gltf-pipeline");
const fsExtra = require("fs-extra");
const processGltf = gltfPipeline.processGltf;
const gltf = fsExtra.readJsonSync("model.gltf");
const options = {
dracoOptions: {
compressionLevel: 10,
},
};
processGltf(gltf, options).then(function (results) {
fsExtra.writeJsonSync("model-draco.gltf", results.gltf);
});Saving separate textures
const gltfPipeline = require("gltf-pipeline");
const fsExtra = require("fs-extra");
const processGltf = gltfPipeline.processGltf;
const gltf = fsExtra.readJsonSync("model.gltf");
const options = {
separateTextures: true,
};
processGltf(gltf, options).then(function (results) {
fsExtra.writeJsonSync("model-separate.gltf", results.gltf);
// Save separate resources
const separateResources = results.separateResources;
for (const relativePath in separateResources) {
if (separateResources.hasOwnProperty(relativePath)) {
const resource = separateResources[relativePath];
fsExtra.writeFileSync(relativePath, resource);
}
}
});Command-Line Flags
| Flag | Description | Required |
|---|---|---|
--help, -h |
Display help | No |
--input, -i |
Path to the glTF or glb file. | :white_check_mark: Yes |
--output, -o |
Output path of the glTF or glb file. Separate resources will be saved to the same directory. | No |
--binary, -b |
Convert the input glTF to glb. | No, default false |
--json, -j |
Convert the input glb to glTF. | No, default false |
--separate, -s |
Write separate buffers, shaders, and textures instead of embedding them in the glTF. | No, default false |
--separateTextures, -t |
Write out separate textures only. | No, default false |
--stats |
Print statistics to console for output glTF file. | No, default false |
--keepUnusedElements |
Keep unused materials, nodes and meshes. | No, default false |
--keepLegacyExtensions |
When false, materials with KHR_techniques_webgl, KHR_blend, or KHR_materials_common will be converted to PBR. |
No, default false |
--draco.compressMeshes, -d |
Compress the meshes using Draco. Adds the KHR_draco_mesh_compression extension. |
No, default false |
--draco.compressionLevel |
Draco compression level [0-10], most is 10, least is 0. A value of 0 will apply sequential encoding and preserve face order. | No, default 7 |
--draco.quantizePositionBits |
Quantization bits for position attribute when using Draco compression. | No, default 11 |
--draco.quantizeNormalBits |
Quantization bits for normal attribute when using Draco compression. | No, default 8 |
--draco.quantizeTexcoordBits |
Quantization bits for texture coordinate attribute when using Draco compression. | No, default 10 |
--draco.quantizeColorBits |
Quantization bits for color attribute when using Draco compression. | No, default 8 |
--draco.quantizeGenericBits |
Quantization bits for skinning attribute (joint indices and joint weights) and custom attributes when using Draco compression. | No, default 8 |
--draco.unifiedQuantization |
Quantize positions of all primitives using the same quantization grid. If not set, quantization is applied separately. | No, default false |
--draco.uncompressedFallback |
Adds uncompressed fallback versions of the compressed meshes. | No, default false |
--baseColorTextureNames |
Names of uniforms that should be considered to refer to base color textures when updating from the KHR_techniques_webgl extension to PBR materials. |
No. (The defaults are not specified here) |
--baseColorFactorNames |
Names of uniforms that should be considered to refer to base color factors when updating from the KHR_techniques_webgl extension to PBR materials. |
No. (The defaults are not specified here) |
Build Instructions
Run the tests:
npm run testTo run ESLint on the entire codebase, run:
npm run eslintTo run ESLint automatically when a file is saved, run the following and leave it open in a console window:
npm run eslint-watchBuilding for CesiumJS integration
Some functionality of gltf-pipeline is used by CesiumJS as a third party library. The necessary files can be generated using:
npm run build-cesiumThis will output a portion of the gltf-pipeline code into the dist/cesium folder for use with CesiumJS in the browser. Copy the files into Source/Scene/GltfPipeline/ in the cesium repository and submit a pull request.
Running Test Coverage
Coverage uses nyc. Run:
npm run coverageFor complete coverage details, open coverage/lcov-report/index.html.
The tests and coverage covers the Node.js module; it does not cover the command-line interface, which is tiny.
Generating Documentation
To generate the documentation:
npm run jsdocThe documentation will be placed in the doc folder.
Contributions
Pull requests are appreciated! Please use the same Contributor License Agreement (CLA) and Coding Guide used for Cesium.