/tinyobjloader

Tiny but powerful single file wavefront obj loader

Primary LanguageC++

tinyobjloader

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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

Rungholt

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

Use case

TinyObjLoader is successfully used in ...

New version(v1.0.x)

Old version(v0.9.x)

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.