Lunarsong / tinygltf

Header only C++11 tiny glTF 2.0 library

Header only C++ tiny glTF library(loader/saver).

TinyGLTF is a header only C++11 glTF 2.0 https://github.com/KhronosGroup/glTF library.

TinyGLTF uses Niels Lohmann's json library(https://github.com/nlohmann/json), so now it requires C++11 compiler. If you are looking for old, C++03 version, please use devel-picojson branch.

Status

v2.0.0 release(22 Aug, 2018)!

Builds

Features

• Written in portable C++. C++-11 with STL dependency only.
  • macOS + clang(LLVM)
  • iOS + clang
  • Linux + gcc/clang
  • Windows + MinGW
  • Windows + Visual Studio 2015 Update 3 or later.
    • Visual Studio 2013 is not supported since they have limited C++11 support and failed to compile json.hpp.
  • Android NDK
  • Android + CrystaX(NDK drop-in replacement) GCC
  • Web using Emscripten(LLVM)
• Moderate parsing time and memory consumption.
• glTF specification v2.0.0
  • ASCII glTF
  • Binary glTF(GLB)
  • PBR material description
• Buffers
  • Parse BASE64 encoded embedded buffer data(DataURI).
  • Load .bin file.
• Image(Using stb_image)
  • Parse BASE64 encoded embedded image data(DataURI).
  • Load external image file.
  • PNG(8bit only)
  • JPEG(8bit only)
  • BMP
  • GIF
  • Custom Image decoder callback(e.g. for decoding OpenEXR image)
• Load from memory
• Custom callback handler
  • Image load
• Extensions
  • Draco mesh decoding

Examples

• glview : Simple glTF geometry viewer.
• validator : Simple glTF validator with JSON schema.
• basic : Basic glTF viewer with texturing support.

Projects using TinyGLTF

• px_render Single header C++ Libraries for Thread Scheduling, Rendering, and so on... https://github.com/pplux/px
• Physical based rendering with Vulkan using glTF 2.0 models https://github.com/SaschaWillems/Vulkan-glTF-PBR
• GLTF loader plugin for OGRE 2.1. Support for PBR materials via HLMS/PBS https://github.com/Ybalrid/Ogre_glTF
• TinyGltfImporter plugin for Magnum, a lightweight and modular C++11/C++14 graphics middleware for games and data visualization.
• Your projects here! (Please send PR)

TODOs

• Write C++ code generator which emits C++ code from JSON schema for robust parsing.
• Mesh Compression/decompression(Open3DGC, etc)
  • Load Draco compressed mesh
  • Save Draco compressed mesh
• Support extensions and extras property
• HDR image?
  • OpenEXR extension through TinyEXR.
• Write example and tests for animation and skin
  • Skinning
  • Morph targets

Licenses

TinyGLTF is licensed under MIT license.

TinyGLTF uses the following third party libraries.

• json.hpp : Copyright (c) 2013-2017 Niels Lohmann. MIT license.
• base64 : Copyright (C) 2004-2008 René Nyffenegger
• stb_image.h : v2.08 - public domain image loader - Github link
• stb_image_write.h : v1.09 - public domain image writer - Github link

Build and example

Copy stb_image.h, stb_image_write.h, json.hpp and tiny_gltf.h to your project.

Loading glTF 2.0 model

// Define these only in *one* .cc file.
#define TINYGLTF_IMPLEMENTATION
#define STB_IMAGE_IMPLEMENTATION
#define STB_IMAGE_WRITE_IMPLEMENTATION
// #define TINYGLTF_NOEXCEPTION // optional. disable exception handling.
#include "tiny_gltf.h"

using namespace tinygltf;

Model model; 
TinyGLTF loader;
std::string err;
std::string warn;
  
bool ret = loader.LoadASCIIFromFile(&model, &err, &warn, argv[1]);
//bool ret = loader.LoadBinaryFromFile(&model, &err, &warn, argv[1]); // for binary glTF(.glb) 

if (!warn.empty()) {
  printf("Warn: %s\n", warn.c_str());
}

if (!err.empty()) {
  printf("Err: %s\n", err.c_str());
}

if (!ret) {
  printf("Failed to parse glTF\n");
  return -1;
}

Compile options

• TINYGLTF_NOEXCEPTION : Disable C++ exception in JSON parsing. You can use -fno-exceptions or by defining the symbol JSON_NOEXCEPTION and TINYGLTF_NOEXCEPTION to fully remove C++ exception codes when compiling TinyGLTF.
• TINYGLTF_NO_STB_IMAGE : Do not load images with stb_image. Instead use TinyGLTF::SetImageLoader(LoadimageDataFunction LoadImageData, void *user_data) to set a callback for loading images.
• TINYGLTF_NO_STB_IMAGE_WRITE : Do not write images with stb_image_write. Instead use TinyGLTF::SetImageWriter(WriteimageDataFunction WriteImageData, void *user_data) to set a callback for writing images.
• TINYGLTF_NO_EXTERNAL_IMAGE : Do not try to load external image file. This option woulde be helpful if you do not want load image file during glTF parsing.
• TINYGLTF_ANDROID_LOAD_FROM_ASSETS: Load all files from packaged app assets instead of the regular file system. Note: You must pass a valid asset manager from your android app to tinygltf::asset_manager beforehand.
• TINYGLTF_ENABLE_DRACO: Enable Draco compression. User must provide include path and link correspnding libraries in your project file.

Saving gltTF 2.0 model

• Buffers.
  • To file
  • Embedded
  • Draco compressed?
• Images
  • To file
  • Embedded
• Binary(.glb)

Running tests.

glTF parsing test

Setup

Python 2.6 or 2.7 required. Git clone https://github.com/KhronosGroup/glTF-Sample-Models to your local dir.

Run parsing test

After building loader_example, edit test_runner.py, then,

$ python test_runner.py

Unit tests

$ cd tests
$ make
$ ./tester
$ ./tester_noexcept

Third party licenses

• json.hpp : Licensed under the MIT License http://opensource.org/licenses/MIT. Copyright (c) 2013-2017 Niels Lohmann http://nlohmann.me.
• stb_image : Public domain.
• catch : Copyright (c) 2012 Two Blue Cubes Ltd. All rights reserved. Distributed under the Boost Software License, Version 1.0.