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tinyobjloader

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Tiny but powerful single file wavefront obj loader written in C++03. No dependency except for C++ STL. It can parse over 10M polygons with moderate memory and time.

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

If you are looking for C99 version, please see https://github.com/syoyo/tinyobjloader-c .

Version notice

We recommend to use master(main) branch. Its v2.0 release candidate. Most features are now nearly robust and stable(Remaining task for release v2.0 is polishing C++ and Python API, and fix built-in triangulation code).

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

What's new

Requirements

Old version

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

Example

Rungholt

tinyobjloader can successfully load 6M triangles Rungholt scene. http://casual-effects.com/data/index.html

Use case

TinyObjLoader is successfully used in ...

New version(v1.0.x)

Old version(v0.9.x)

Features

Primitives

Material

TODO

License

TinyObjLoader is licensed under MIT license.

Third party licenses.

Usage

Installation

One option is to simply copy the header file into your project and to make sure that TINYOBJLOADER_IMPLEMENTATION is defined exactly once.

Building tinyobjloader - Using vcpkg(not recommended though)

Although it is not a recommended way, you can download and install tinyobjloader using the vcpkg dependency manager:

git clone https://github.com/Microsoft/vcpkg.git
cd vcpkg
./bootstrap-vcpkg.sh
./vcpkg integrate install
./vcpkg install tinyobjloader

The tinyobjloader port in vcpkg is kept up to date by Microsoft team members and community contributors. If the version is out of date, please create an issue or pull request on the vcpkg repository.

Data format

attrib_t contains single and linear array of vertex data(position, normal and texcoord).

attrib_t::vertices => 3 floats per vertex

       v[0]        v[1]        v[2]        v[3]               v[n-1]
  +-----------+-----------+-----------+-----------+      +-----------+
  | x | y | z | x | y | z | x | y | z | x | y | z | .... | x | y | z |
  +-----------+-----------+-----------+-----------+      +-----------+

attrib_t::normals => 3 floats per vertex

       n[0]        n[1]        n[2]        n[3]               n[n-1]
  +-----------+-----------+-----------+-----------+      +-----------+
  | x | y | z | x | y | z | x | y | z | x | y | z | .... | x | y | z |
  +-----------+-----------+-----------+-----------+      +-----------+

attrib_t::texcoords => 2 floats per vertex

       t[0]        t[1]        t[2]        t[3]               t[n-1]
  +-----------+-----------+-----------+-----------+      +-----------+
  |  u  |  v  |  u  |  v  |  u  |  v  |  u  |  v  | .... |  u  |  v  |
  +-----------+-----------+-----------+-----------+      +-----------+

attrib_t::colors => 3 floats per vertex(vertex color. optional)

       c[0]        c[1]        c[2]        c[3]               c[n-1]
  +-----------+-----------+-----------+-----------+      +-----------+
  | x | y | z | x | y | z | x | y | z | x | y | z | .... | x | y | z |
  +-----------+-----------+-----------+-----------+      +-----------+

Each shape_t::mesh_t does not contain vertex data but contains array index to attrib_t. See loader_example.cc for more details.


mesh_t::indices => array of vertex indices.

  +----+----+----+----+----+----+----+----+----+----+     +--------+
  | i0 | i1 | i2 | i3 | i4 | i5 | i6 | i7 | i8 | i9 | ... | i(n-1) |
  +----+----+----+----+----+----+----+----+----+----+     +--------+

Each index has an array index to attrib_t::vertices, attrib_t::normals and attrib_t::texcoords.

mesh_t::num_face_vertices => array of the number of vertices per face(e.g. 3 = triangle, 4 = quad , 5 or more = N-gons).


  +---+---+---+        +---+
  | 3 | 4 | 3 | ...... | 3 |
  +---+---+---+        +---+
    |   |   |            |
    |   |   |            +-----------------------------------------+
    |   |   |                                                      |
    |   |   +------------------------------+                       |
    |   |                                  |                       |
    |   +------------------+               |                       |
    |                      |               |                       |
    |/                     |/              |/                      |/

 mesh_t::indices

  |    face[0]   |       face[1]     |    face[2]   |     |      face[n-1]           |
  +----+----+----+----+----+----+----+----+----+----+     +--------+--------+--------+
  | i0 | i1 | i2 | i3 | i4 | i5 | i6 | i7 | i8 | i9 | ... | i(n-3) | i(n-2) | i(n-1) |
  +----+----+----+----+----+----+----+----+----+----+     +--------+--------+--------+

Note that when triangulate flag is true in tinyobj::LoadObj() argument, num_face_vertices are all filled with 3(triangle).

float data type

TinyObjLoader now use real_t for floating point data type. Default is float(32bit). You can enable double(64bit) precision by using TINYOBJLOADER_USE_DOUBLE define.

Robust triangulation

When you enable triangulation(default is enabled), TinyObjLoader triangulate polygons(faces with 4 or more vertices).

Built-in triangulation code may not work well in some polygon shape.

You can define TINYOBJLOADER_USE_MAPBOX_EARCUT for robust triangulation using mapbox/earcut.hpp. This requires C++11 compiler though. And you need to copy mapbox/earcut.hpp to your project. If you have your own mapbox/earcut.hpp file incuded in your project, you can define TINYOBJLOADER_DONOT_INCLUDE_MAPBOX_EARCUT so that mapbox/earcut.hpp is not included inside of tiny_obj_loader.h.

Example code (Deprecated API)

#define TINYOBJLOADER_IMPLEMENTATION // define this in only *one* .cc
// Optional. define TINYOBJLOADER_USE_MAPBOX_EARCUT gives robust triangulation. Requires C++11
//#define TINYOBJLOADER_USE_MAPBOX_EARCUT
#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 warn;
std::string err;

bool ret = tinyobj::LoadObj(&attrib, &shapes, &materials, &warn, &err, inputfile.c_str());

if (!warn.empty()) {
  std::cout << warn << std::endl;
}

if (!err.empty()) {
  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++) {
    size_t fv = size_t(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];

      tinyobj::real_t vx = attrib.vertices[3*size_t(idx.vertex_index)+0];
      tinyobj::real_t vy = attrib.vertices[3*size_t(idx.vertex_index)+1];
      tinyobj::real_t vz = attrib.vertices[3*size_t(idx.vertex_index)+2];

      // Check if `normal_index` is zero or positive. negative = no normal data
      if (idx.normal_index >= 0) {
        tinyobj::real_t nx = attrib.normals[3*size_t(idx.normal_index)+0];
        tinyobj::real_t ny = attrib.normals[3*size_t(idx.normal_index)+1];
        tinyobj::real_t nz = attrib.normals[3*size_t(idx.normal_index)+2];
      }

      // Check if `texcoord_index` is zero or positive. negative = no texcoord data
      if (idx.texcoord_index >= 0) {
        tinyobj::real_t tx = attrib.texcoords[2*size_t(idx.texcoord_index)+0];
        tinyobj::real_t ty = attrib.texcoords[2*size_t(idx.texcoord_index)+1];
      }
      // Optional: vertex colors
      // tinyobj::real_t red   = attrib.colors[3*size_t(idx.vertex_index)+0];
      // tinyobj::real_t green = attrib.colors[3*size_t(idx.vertex_index)+1];
      // tinyobj::real_t blue  = attrib.colors[3*size_t(idx.vertex_index)+2];
    }
    index_offset += fv;

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

Example code (New Object Oriented API)

#define TINYOBJLOADER_IMPLEMENTATION // define this in only *one* .cc
// Optional. define TINYOBJLOADER_USE_MAPBOX_EARCUT gives robust triangulation. Requires C++11
//#define TINYOBJLOADER_USE_MAPBOX_EARCUT
#include "tiny_obj_loader.h"


std::string inputfile = "cornell_box.obj";
tinyobj::ObjReaderConfig reader_config;
reader_config.mtl_search_path = "./"; // Path to material files

tinyobj::ObjReader reader;

if (!reader.ParseFromFile(inputfile, reader_config)) {
  if (!reader.Error().empty()) {
      std::cerr << "TinyObjReader: " << reader.Error();
  }
  exit(1);
}

if (!reader.Warning().empty()) {
  std::cout << "TinyObjReader: " << reader.Warning();
}

auto& attrib = reader.GetAttrib();
auto& shapes = reader.GetShapes();
auto& materials = reader.GetMaterials();

// 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++) {
    size_t fv = size_t(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];
      tinyobj::real_t vx = attrib.vertices[3*size_t(idx.vertex_index)+0];
      tinyobj::real_t vy = attrib.vertices[3*size_t(idx.vertex_index)+1];
      tinyobj::real_t vz = attrib.vertices[3*size_t(idx.vertex_index)+2];

      // Check if `normal_index` is zero or positive. negative = no normal data
      if (idx.normal_index >= 0) {
        tinyobj::real_t nx = attrib.normals[3*size_t(idx.normal_index)+0];
        tinyobj::real_t ny = attrib.normals[3*size_t(idx.normal_index)+1];
        tinyobj::real_t nz = attrib.normals[3*size_t(idx.normal_index)+2];
      }

      // Check if `texcoord_index` is zero or positive. negative = no texcoord data
      if (idx.texcoord_index >= 0) {
        tinyobj::real_t tx = attrib.texcoords[2*size_t(idx.texcoord_index)+0];
        tinyobj::real_t ty = attrib.texcoords[2*size_t(idx.texcoord_index)+1];
      }

      // Optional: vertex colors
      // tinyobj::real_t red   = attrib.colors[3*size_t(idx.vertex_index)+0];
      // tinyobj::real_t green = attrib.colors[3*size_t(idx.vertex_index)+1];
      // tinyobj::real_t blue  = attrib.colors[3*size_t(idx.vertex_index)+2];
    }
    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).

Python binding

$ python -m pip install tinyobjloader

See python/sample.py for example use of Python binding of tinyobjloader.

CI + PyPI upload

cibuildwheels + twine upload for each git tagging event is handled in Github Actions and Cirrus CI(arm builds).

How to bump version(For developer)

Tests

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