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 ;-)

What's new

• XX YY, ZZZZ : New data strcutre and API!
• Jan 29, 2016 : Support n-polygon(no triangulation) and OpenSubdiv crease tag! Thanks dboogert!
• Nov 26, 2015 : Now single-header only!.
• Nov 08, 2015 : Improved API.
• Jun 23, 2015 : Various fixes and added more projects using tinyobjloader. Thanks many contributors!
• Mar 03, 2015 : Replace atof() with hand-written parser for robust reading of numeric value. Thanks skurmedel!
• Feb 06, 2015 : Fix parsing multi-material object
• Sep 14, 2014 : Add support for multi-material per object/group. Thanks Mykhailo!
• Mar 17, 2014 : Fixed trim newline bugs. Thanks ardneran!
• Apr 29, 2014 : Add API to read .obj from std::istream. Good for reading compressed .obj or connecting to procedural primitive generator. Thanks burnse!
• Apr 21, 2014 : Define default material if no material definition exists in .obj. Thanks YarmUI!
• Apr 10, 2014 : Add support for parsing 'illum' and 'd'/'Tr' statements. Thanks mmp!
• Jan 27, 2014 : Added CMake project. Thanks bradc6!
• Nov 26, 2013 : Performance optimization by NeuralSandwich. 9% improvement in his project, thanks!
• Sep 12, 2013 : Added multiple .obj sticher example.

Example

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

• examples/viewer/ OpenGL .obj viewer

Use case

TinyObjLoader is successfully used in ...

• 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
• Your project here!

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)
• Callback API for custom loading.

TODO

• Fix Python binding.
• Fix obj_sticker example.
• More unit test codes.

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.