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tinyobjloader
=============
http://syoyo.github.io/tinyobjloader/
Tiny but poweful 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.
Good for embedding .obj loader to your (global illumination) renderer ;-)
Example
-------
tinyobjloader can successfully load 6M triangles Rungholt scene.
http://graphics.cs.williams.edu/data/meshes.xml
Features
--------
* Group
* Vertex
* Texcoord
* Normal
* Material
* Unknown material attributes are treated as key-value.
Notes
-----
Polygon is converted into triangle.
License
-------
Licensed under 2 clause BSD.
Usage
-----
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) |
+----+----+----+----+----+----+----+----+----+----+ +--------+--------+--------+
```c++
#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;
LoadObj(attrib, shapes, inputfile.c_str());
// 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.indices.size(); f++) {
int fv = 3;
// 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*idx.vertex_index+0];
tinyobj::real_t vy = attrib.vertices[3*idx.vertex_index+1];
tinyobj::real_t vz = attrib.vertices[3*idx.vertex_index+2];
tinyobj::real_t nx = attrib.normals[3*idx.normal_index+0];
tinyobj::real_t ny = attrib.normals[3*idx.normal_index+1];
tinyobj::real_t nz = attrib.normals[3*idx.normal_index+2];
tinyobj::real_t tx = attrib.texcoords[2*idx.texcoord_index+0];
tinyobj::real_t ty = attrib.texcoords[2*idx.texcoord_index+1];
}
index_offset += fv;
}
}
```
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