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Initial commit.

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Syoyo Fujita
2012-08-19 14:36:48 +09:00
commit cf78dd845b
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//
// Copyright 2012, Syoyo Fujita.
//
// Licensed under 2-clause BSD liecense.
//
//
// version 0.9.0: Initial
//
//
// @todo { Read .mtl }
//
#include <cassert>
#include <string>
#include <vector>
#include <map>
#include <fstream>
#include <sstream>
#include "tiny_obj_loader.h"
namespace tinyobj {
struct vertex_index {
int v_idx, vt_idx, vn_idx;
vertex_index() {};
vertex_index(int idx) : v_idx(idx), vt_idx(idx), vn_idx(idx) {};
vertex_index(int vidx, int vtidx, int vnidx) : v_idx(vidx), vt_idx(vtidx), vn_idx(vnidx) {};
};
// for std::map
static inline bool operator<(const vertex_index& a, const vertex_index& b)
{
if (a.v_idx != b.v_idx) return (a.v_idx < b.v_idx);
if (a.vn_idx != b.vn_idx) return (a.vn_idx < b.vn_idx);
if (a.vt_idx != b.vt_idx) return (a.vt_idx < b.vt_idx);
return false;
}
struct obj_shape {
std::vector<float> v;
std::vector<float> vn;
std::vector<float> vt;
};
static inline bool isSpace(const char c) {
return (c == ' ') || (c == '\t');
}
// Make index zero-base, and also support relative index.
static inline int fixIndex(int idx, int n)
{
int i;
if (idx > 0) {
i = idx - 1;
} else if (idx == 0) {
i = 0;
} else { // negative value = relative
i = n + idx;
}
return i;
}
static inline float parseFloat(const char*& token)
{
token += strspn(token, " \t");
float f = (float)atof(token);
token += strcspn(token, " \t\r");
return f;
}
static inline void parseFloat2(
float& x, float& y,
const char*& token)
{
x = parseFloat(token);
y = parseFloat(token);
}
static inline void parseFloat3(
float& x, float& y, float& z,
const char*& token)
{
x = parseFloat(token);
y = parseFloat(token);
z = parseFloat(token);
}
// Parse triples: i, i/j/k, i//k, i/j
static vertex_index parseTriple(
const char* &token,
int vsize,
int vnsize,
int vtsize)
{
vertex_index vi(-1);
vi.v_idx = fixIndex(atoi(token), vsize);
token += strcspn(token, "/ \t\r");
if (token[0] != '/') {
return vi;
}
token++;
// i//k
if (token[0] == '/') {
token++;
vi.vn_idx = fixIndex(atoi(token), vnsize);
token += strcspn(token, "/ \t\r");
return vi;
}
// i/j/k or i/j
vi.vt_idx = fixIndex(atoi(token), vtsize);
token += strcspn(token, "/ \t\r");
if (token[0] != '/') {
return vi;
}
// i/j/k
vi.vn_idx = fixIndex(atoi(token), vnsize);
token += strcspn(token, "/ \t\r");
return vi;
}
static unsigned int
updateVertex(
std::map<vertex_index, unsigned int>& vertexCache,
std::vector<float>& positions,
std::vector<float>& normals,
std::vector<float>& texcoords,
const std::vector<float>& in_positions,
const std::vector<float>& in_normals,
const std::vector<float>& in_texcoords,
const vertex_index& i)
{
const std::map<vertex_index, unsigned int>::iterator it = vertexCache.find(i);
if (it != vertexCache.end()) {
// found cache
return it->second;
}
assert(in_positions.size() > (3*i.v_idx+2));
positions.push_back(in_positions[3*i.v_idx+0]);
positions.push_back(in_positions[3*i.v_idx+1]);
positions.push_back(in_positions[3*i.v_idx+2]);
if (i.vn_idx >= 0) {
normals.push_back(in_normals[3*i.vn_idx+0]);
normals.push_back(in_normals[3*i.vn_idx+1]);
normals.push_back(in_normals[3*i.vn_idx+2]);
}
if (i.vt_idx >= 0) {
texcoords.push_back(in_texcoords[3*i.vt_idx+0]);
texcoords.push_back(in_texcoords[3*i.vt_idx+1]);
texcoords.push_back(in_texcoords[3*i.vt_idx+2]);
}
unsigned int idx = positions.size() / 3 - 1;
vertexCache[i] = idx;
return idx;
}
static bool
exportFaceGroupToShape(
shape_t& shape,
const std::vector<float> in_positions,
const std::vector<float> in_normals,
const std::vector<float> in_texcoords,
const std::vector<std::vector<vertex_index> >& faceGroup,
const std::string name)
{
if (faceGroup.empty()) {
return false;
}
// Flattened version of vertex data
std::vector<float> positions;
std::vector<float> normals;
std::vector<float> texcoords;
std::map<vertex_index, unsigned int> vertexCache;
std::vector<unsigned int> indices;
// Flatten vertices and indices
for (size_t i = 0; i < faceGroup.size(); i++) {
const std::vector<vertex_index>& face = faceGroup[i];
vertex_index i0 = face[0];
vertex_index i1(-1);
vertex_index i2 = face[1];
size_t npolys = face.size();
// Polygon -> triangle fan conversion
for (size_t k = 2; k < npolys; k++) {
i1 = i2;
i2 = face[k];
unsigned int v0 = updateVertex(vertexCache, positions, normals, texcoords, in_positions, in_normals, in_texcoords, i0);
unsigned int v1 = updateVertex(vertexCache, positions, normals, texcoords, in_positions, in_normals, in_texcoords, i1);
unsigned int v2 = updateVertex(vertexCache, positions, normals, texcoords, in_positions, in_normals, in_texcoords, i2);
indices.push_back(v0);
indices.push_back(v1);
indices.push_back(v2);
}
}
//
// Construct shape.
//
shape.name = name;
shape.mesh.positions.swap(positions);
shape.mesh.normals.swap(normals);
shape.mesh.texcoords.swap(texcoords);
shape.mesh.indices.swap(indices);
// @todo { material, name }
return true;
}
std::string
LoadObj(
std::vector<shape_t>& shapes,
const char* filename)
{
shapes.clear();
std::stringstream err;
std::ifstream ifs(filename);
if (!ifs) {
err << "Cannot open file [" << filename << "]" << std::endl;
return err.str();
}
std::vector<float> v;
std::vector<float> vn;
std::vector<float> vt;
std::vector<std::vector<vertex_index> > faceGroup;
std::string name;
int maxchars = 8192; // Alloc enough size.
std::vector<char> buf(maxchars); // Alloc enough size.
while (ifs.peek() != -1) {
ifs.getline(&buf[0], maxchars);
std::string linebuf(&buf[0]);
// Trim newline '\r\n' or '\r'
if (linebuf.size() > 0) {
if (linebuf[linebuf.size()-1] == '\n') linebuf.erase(linebuf.size()-1);
}
if (linebuf.size() > 0) {
if (linebuf[linebuf.size()-1] == '\n') linebuf.erase(linebuf.size()-1);
}
// Skip if empty line.
if (linebuf.empty()) {
continue;
}
// Skip leading space.
const char* token = linebuf.c_str();
token += strspn(token, " \t");
assert(token);
if (token[0] == '\0') continue; // empty line
if (token[0] == '#') continue; // comment line
// vertex
if (token[0] == 'v' && isSpace((token[1]))) {
token += 2;
float x, y, z;
parseFloat3(x, y, z, token);
v.push_back(x);
v.push_back(y);
v.push_back(z);
continue;
}
// normal
if (token[0] == 'v' && token[1] == 'n' && isSpace((token[2]))) {
token += 3;
float x, y, z;
parseFloat3(x, y, z, token);
vn.push_back(x);
vn.push_back(y);
vn.push_back(z);
continue;
}
// texcoord
if (token[0] == 'v' && token[1] == 't' && isSpace((token[2]))) {
token += 3;
float x, y;
parseFloat2(x, y, token);
vt.push_back(x);
vt.push_back(y);
continue;
}
// face
if (token[0] == 'f' && isSpace((token[1]))) {
token += 2;
token += strspn(token, " \t");
std::vector<vertex_index> face;
while (token[0] && (token[1] != '\0')) {
vertex_index vi = parseTriple(token, v.size() / 3, vn.size() / 3, vt.size() / 2);
face.push_back(vi);
int n = strspn(token, " \t");
token += n;
}
faceGroup.push_back(face);
continue;
}
// use mtl
if ((0 == strncmp(token, "usemtl", 6)) && isSpace((token[6]))) {
// flush previous face group.
shape_t shape;
bool ret = exportFaceGroupToShape(shape, v, vn, vt, faceGroup, name);
if (ret) {
shapes.push_back(shape);
}
faceGroup.clear();
continue;
}
// load mtl
if ((0 == strncmp(token, "mtllib", 6)) && isSpace((token[6]))) {
continue;
}
// object name
if (token[0] == 'o' && isSpace((token[1]))) {
char namebuf[4096];
token += 2;
sscanf(token, "%s", namebuf);
name = std::string(namebuf);
continue;
}
// Ignore unknown command.
}
shape_t shape;
bool ret = exportFaceGroupToShape(shape, v, vn, vt, faceGroup, name);
if (ret) {
shapes.push_back(shape);
}
faceGroup.clear(); // for safety
return err.str();
}
};