cgltf

by jkuhlmann

jkuhlmann /cgltf

:diamond_shape_with_a_dot_inside: Single-file glTF 2.0 loader and writer written in C99

522 Stars 34 Forks Last release: about 2 months ago (v1.7) MIT License 294 Commits 8 Releases

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:diamondshapewithadot_inside: cgltf

Single-file/stb-style C glTF loader and writer

Build Status

Used in: bgfx, Filament, meshoptimizer, raylib, and more!

Usage: Loading

Loading from file: ```c

define CGLTF_IMPLEMENTATION

include "cgltf.h"

cgltfoptions options = {0}; cgltfdata* data = NULL; cgltfresult result = cgltfparsefile(&options, "scene.gltf", &data); if (result == cgltfresultsuccess) { /* TODO make awesome stuff */ cgltffree(data); } ```

Loading from memory: ```c

define CGLTF_IMPLEMENTATION

include "cgltf.h"

void* buf; /* Pointer to glb or gltf file data / size_t size; / Size of the file data */

cgltfoptions options = {0}; cgltfdata* data = NULL; cgltfresult result = cgltfparse(&options, buf, size, &data); if (result == cgltfresultsuccess) { /* TODO make awesome stuff */ cgltf_free(data); } ```

Note that cgltf does not load the contents of extra files such as buffers or images into memory by default. You'll need to read these files yourself using URIs from

data.buffers[]
or
data.images[]
respectively. For buffer data, you can alternatively call
cgltf_load_buffers
, which will use
FILE*
APIs to open and read buffer files.

For more in-depth documentation and a description of the public interface refer to the top of the

cgltf.h
file.

Usage: Writing

When writing glTF data, you need a valid

cgltf_data
structure that represents a valid glTF document. You can construct such a structure yourself or load it using the loader functions described above. The writer functions do not deallocate any memory. So, you either have to do it manually or call
cgltf_free()
if you got the data by loading it from a glTF document.

Writing to file: ```c

define CGLTF_IMPLEMENTATION

define CGLTFWRITEIMPLEMENTATION

include "cgltf_write.h"

cgltfoptions options = {0}; cgltfdata* data = /* TODO must be valid data /; cgltfresult result = cgltfwritefile(&options, "out.gltf", data); if (result != cgltfresult_success) { / TODO handle error */ } ```

Writing to memory: ```c

define CGLTF_IMPLEMENTATION

define CGLTFWRITEIMPLEMENTATION

include "cgltf_write.h"

cgltfoptions options = {0}; cgltfdata* data = /* TODO must be valid data */;

cgltfsize size = cgltfwrite(&options, NULL, 0, data);

char* buf = malloc(size);

cgltfsize written = cgltfwrite(&options, buf, size, data); if (written != size) { /* TODO handle error */ } ```

Note that cgltf does not write the contents of extra files such as buffers or images. You'll need to write this data yourself.

Writing does not yet support "extras" data.

For more in-depth documentation and a description of the public interface refer to the top of the

cgltf_write.h
file.

Features

cgltf supports core glTF 2.0: - glb (binary files) and gltf (JSON files) - meshes (including accessors, buffer views, buffers) - materials (including textures, samplers, images) - scenes and nodes - skins - animations - cameras - morph targets - extras data

cgltf also supports some glTF extensions: - KHRdracomeshcompression (requires a library like Google's Draco for decompression though) - KHRlightspunctual - KHRmaterialsclearcoat - KHRmaterialsior - KHRmaterialspbrSpecularGlossiness - KHRmaterialstransmission - KHRmaterialsunlit - KHRtexture_transform

cgltf does not yet support unlisted extensions. However, unlisted extensions can be accessed via "extensions" member on objects.

Building

The easiest approach is to integrate the

cgltf.h
header file into your project. If you are unfamiliar with single-file C libraries (also known as stb-style libraries), this is how it goes:
  1. Include
    cgltf.h
    where you need the functionality.
  2. Have exactly one source file that defines
    CGLTF_IMPLEMENTATION
    before including
    cgltf.h
    .
  3. Use the cgltf functions as described above.

Support for writing can be found in a separate file called

cgltf_write.h
(which includes
cgltf.h
). Building it works analogously using the
CGLTF_WRITE_IMPLEMENTATION
define.

Contributing

Everyone is welcome to contribute to the library. If you find any problems, you can submit them using GitHub's issue system. If you want to contribute code, you should fork the project and then send a pull request.

Dependencies

None.

C headers being used by implementation: ```

include

include

include

include

include

include

Note, this library has a copy of the [JSMN JSON parser](https://github.com/zserge/jsmn) embedded in its source.

Testing

There is a Python script in the test/ folder that retrieves the glTF 2.0 sample files from the glTF-Sample-Models repository (https://github.com/KhronosGroup/glTF-Sample-Models/tree/master/2.0) and runs the library against all gltf and glb files.

Here's one way to build and run the test:

cd test ; mkdir build ; cd build ; cmake .. -DCMAKE_BUILD_TYPE=Debug
make -j
cd ..
./test_all.py

There is also a llvm-fuzz test in fuzz/. See http://llvm.org/docs/LibFuzzer.html for more information.

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