tinyobjloader

http://syoyo.github.io/tinyobjloader/

Tiny but powerful single file wavefront obj loader written in C++. No dependency except for C++ STL. It can parse 10M over polygons with moderate memory and time.

tinyobjloader is good for embedding .obj loader to your (global illumination) renderer ;-)

If you are looking for C89 version, please see https://github.com/syoyo/tinyobjloader-c .

Notice!

We have released new version v1.0.0 on 20 Aug, 2016. Old version is available v0.9.x branch https://github.com/syoyo/tinyobjloader/tree/v0.9.x

What's new

• 20 Aug, 2016 : Bump version v1.0.0. New data strcutre and API!

Old version

Previous old version is avaiable in v0.9.x branch.

Example

tinyobjloader can successfully load 6M triangles Rungholt scene. http://graphics.cs.williams.edu/data/meshes.xml

• examples/viewer/ OpenGL .obj viewer
• examples/callback_api/ Callback API example
• examples/voxelize/ Voxelizer example

Use case

TinyObjLoader is successfully used in ...

New version(v1.0.x)

• Loading models in Vulkan Tutorial https://vulkan-tutorial.com/Loading_models
• .obj viewer with Metal https://github.com/middlefeng/NuoModelViewer/tree/master
• Your project here!

Old version(v0.9.x)

• bullet3 https://github.com/erwincoumans/bullet3
• pbrt-v2 https://github.com/mmp/pbrt-v2
• OpenGL game engine development http://swarminglogic.com/jotting/2013_10_gamedev01
• mallie https://lighttransport.github.io/mallie
• IBLBaker (Image Based Lighting Baker). http://www.derkreature.com/iblbaker/
• Stanford CS148 http://web.stanford.edu/class/cs148/assignments/assignment3.pdf
• Awesome Bump http://awesomebump.besaba.com/about/
• sdlgl3-wavefront OpenGL .obj viewer https://github.com/chrisliebert/sdlgl3-wavefront
• pbrt-v3 https://github.com/mmp/pbrt-v3
• cocos2d-x https://github.com/cocos2d/cocos2d-x/
• Android Vulkan demo https://github.com/SaschaWillems/Vulkan
• voxelizer https://github.com/karimnaaji/voxelizer
• Probulator https://github.com/kayru/Probulator
• OptiX Prime baking https://github.com/nvpro-samples/optix_prime_baking
• FireRays SDK https://github.com/GPUOpen-LibrariesAndSDKs/FireRays_SDK
• parg, tiny C library of various graphics utilities and GL demos https://github.com/prideout/parg
• Opengl unit of ChronoEngine https://github.com/projectchrono/chrono-opengl
• Point Based Global Illumination on modern GPU https://pbgi.wordpress.com/code-source/
• Fast OBJ file importing and parsing in CUDA http://researchonline.jcu.edu.au/42515/1/2015.CVM.OBJCUDA.pdf
• Sorted Shading for Uni-Directional Pathtracing by Joshua Bainbridge https://nccastaff.bournemouth.ac.uk/jmacey/MastersProjects/MSc15/02Josh/joshua_bainbridge_thesis.pdf
• GeeXLab http://www.geeks3d.com/hacklab/20160531/geexlab-0-12-0-0-released-for-windows/

Features

• Group(parse multiple group name)
• Vertex
• Texcoord
• Normal
• Material
  • Unknown material attributes are returned as key-value(value is string) map.
• Crease tag('t'). This is OpenSubdiv specific(not in wavefront .obj specification)
• PBR material extension for .MTL. Its proposed here: http://exocortex.com/blog/extending_wavefront_mtl_to_support_pbr
• Callback API for custom loading.

TODO

• Fix obj_sticker example.
• More unit test codes.
• Texture options
• Normal vector generation
  • Support smoothing groups

License

Licensed under MIT license.

Usage

attrib_t contains single and linear array of vertex data(position, normal and texcoord). Each shape_t does not contain vertex data but contains array index to attrib_t. See loader_example.cc for more details.

#define TINYOBJLOADER_IMPLEMENTATION // define this in only *one* .cc
#include "tiny_obj_loader.h"

std::string inputfile = "cornell_box.obj";
tinyobj::attrib_t attrib;
std::vector<tinyobj::shape_t> shapes;
std::vector<tinyobj::material_t> materials;
  
std::string err;
bool ret = tinyobj::LoadObj(&attrib, &shapes, &materials, &err, inputfile.c_str());
  
if (!err.empty()) { // `err` may contain warning message.
  std::cerr << err << std::endl;
}

if (!ret) {
  exit(1);
}

// Loop over shapes
for (size_t s = 0; s < shapes.size(); s++) {
  // Loop over faces(polygon)
  size_t index_offset = 0;
  for (size_t f = 0; f < shapes[s].mesh.num_face_vertices.size(); f++) {
    int fv = shapes[s].mesh.num_face_vertices[f];

    // Loop over vertices in the face.
    for (size_t v = 0; v < fv; v++) {
      // access to vertex
      tinyobj::index_t idx = shapes[s].mesh.indices[index_offset + v];
      float vx = attrib.vertices[3*idx.vertex_index+0];
      float vy = attrib.vertices[3*idx.vertex_index+1];
      float vz = attrib.vertices[3*idx.vertex_index+2];
      float nx = attrib.normals[3*idx.normal_index+0];
      float ny = attrib.normals[3*idx.normal_index+1];
      float nz = attrib.normals[3*idx.normal_index+2];
      float tx = attrib.texcoords[2*idx.texcoord_index+0];
      float ty = attrib.texcoords[2*idx.texcoord_index+1];
    }
    index_offset += fv;

    // per-face material
    shapes[s].mesh.material_ids[f];
  }
}

Optimized loader

Optimized multi-threaded .obj loader is available at experimental/ directory. If you want absolute performance to load .obj data, this optimized loader will fit your purpose. Note that the optimized loader uses C++11 thread and it does less error checks but may work most .obj data.

Here is some benchmark result. Time are measured on MacBook 12(Early 2016, Core m5 1.2GHz).

• Rungholt scene(6M triangles)
  • old version(v0.9.x): 15500 msecs.
  • baseline(v1.0.x): 6800 msecs(2.3x faster than old version)
  • optimised: 1500 msecs(10x faster than old version, 4.5x faster than basedline)

Tests

Unit tests are provided in tests directory. See tests/README.md for details.