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#include "obj_parser.h"
#include <iostream>
#include <fstream>
#include <string>
#include <vector>
#include <cstddef>
#include <array>
#include "math/vector.h"
#include "o3d/mesh.h"
#include "o3d/vertex_data.h"
namespace engine {
namespace {
std::vector<std::string> split(const std::string& s, char sep) {
std::vector<std::string> res;
std::string::size_type last_ind = 0;
for (std::string::size_type ind = 0; ind < s.length(); ind++) {
if (s[ind] == sep) {
res.push_back(s.substr(last_ind, ind - last_ind));
last_ind = ind + 1;
}
}
res.push_back(s.substr(last_ind));
return res;
}
float parse_float(const std::string& s) {
std::string::size_type ind = 0;
bool positive = true;
while (ind < s.length() && (s[ind] == '+' || s[ind] == '-'))
if (s[ind++] == '-')
positive = !positive;
// improve error checking
if (ind == s.length())
return 0.f;
int n = 0;
while (ind < s.length() && s[ind] >= '0' && s[ind] <= '9')
n = n * 10 + static_cast<int>(s[ind++]) - static_cast<int>('0');
if (ind == s.length())
return (positive ? 1.f : -1.f) * static_cast<float>(n);
// improve error checking
if (s[ind] != '.')
return 0.f;
ind++;
float decimal_part = 0.f;
float decimal_fac = .1f;
while (ind < s.length() && s[ind] >= '0' && s[ind] <= '9') {
decimal_part += decimal_fac * static_cast<float>(static_cast<int>(s[ind++]) - static_cast<int>('0'));
decimal_fac *= .1f;
}
// improve error checking
if (ind != s.length())
return 0.f;
return (positive ? 1.f : -1.f) * (static_cast<float>(n) + decimal_part);
}
float parse_int(const std::string& s) {
std::string::size_type ind = 0;
bool positive = true;
while (ind < s.length() && (s[ind] == '+' || s[ind] == '-'))
if (s[ind++] == '-')
positive = !positive;
// improve error checking
if (ind == s.length())
return 0.f;
int n = 0;
while (ind < s.length() && s[ind] >= '0' && s[ind] <= '9')
n = n * 10 + static_cast<int>(s[ind++]) - static_cast<int>('0');
// improve error checking
if (ind != s.length())
return 0.f;
return (positive ? 1.f : -1.f) * n;
}
}
o3d::Mesh parse_object(const std::string& obj_path) {
o3d::Mesh mesh;
mesh.vertices_data.push_back(o3d::VertexData(0.f, 0.f));
std::ifstream obj_file(obj_path);
std::string line;
while (std::getline(obj_file, line)) {
if (line.length() == 0 || line[0] == '#')
continue;
if (line.rfind("o ", 0) == 0) {
// std::cout << "Object: " << line.substr(2) << std::endl;
} else if (line.rfind("v ", 0) == 0) {
auto s_coords = split(line.substr(2), ' ');
math::Vector4 v{parse_float(s_coords[0]), parse_float(s_coords[1]), parse_float(s_coords[2]), 1.f};
// std::cout << "Vertex x: " << v.x << " y: " << v.y << " z: " << v.z << std::endl;
mesh.vertices.push_back(v);
} else if (line.rfind("vn ", 0) == 0) {
auto s_coords = split(line.substr(3), ' ');
math::Vector3 vn{parse_float(s_coords[0]), parse_float(s_coords[1]), parse_float(s_coords[2])};
// std::cout << "Vertex normal x: " << vn.x << " y: " << vn.y << " z: " << vn.z << std::endl;
mesh.normals.push_back(vn);
} else if (line.rfind("s ", 0) == 0) {
// auto smooth = false;
// auto s_smooth = line.substr(2);
// if (s_smooth == "0" || s_smooth == "off") {
// smooth = false;
// } else if (s_smooth == "1" || s_smooth == "on") {
// smooth = true;
// }
// std::cout << "Smooth: " << std::boolalpha << smooth << std::endl;
} else if (line.rfind("f ", 0) == 0) {
std::array<std::array<std::size_t, 3>, 3> indices;
auto line_split = split(line.substr(2), ' ');
for (int i = 0; i < 3; i++) {
auto indices_s_group = split(line_split[i], '/');
indices[i][0] = parse_int(indices_s_group[0]) - 1;
indices[i][1] = parse_int(indices_s_group[2]) - 1;
indices[i][2] = 0;
}
// std::cout << "Face:"
// << " 1: vertex: " << indices[0][0] << " normal: " << indices[0][1]
// << " 2: vertex: " << indices[1][0] << " normal: " << indices[1][1]
// << " 3: vertex: " << indices[2][0] << " normal: " << indices[2][1]
// << std::endl;
mesh.indices.push_back(indices);
}
}
return mesh;
}
}
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