59 lines
2.1 KiB
C++
59 lines
2.1 KiB
C++
#include "object.h"
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#include <fstream>
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// https://en.wikibooks.org/wiki/OpenGL_Programming/Modern_OpenGL_Tutorial_Load_OBJ
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void LoadOBJ(Logger& logger, std::string file, std::vector<glm::vec3>& vertices, std::vector<glm::vec3>& normals, std::vector<GLushort>& elements) {
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std::ifstream in(file, std::ios::in);
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if (!in) {
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logger << LOGGER_ERROR << "Cannot open " << file << LOGGER_ENDL;
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return;
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}
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std::string line;
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while (getline(in, line)) {
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if (line.substr(0,2) == "v ") {
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std::istringstream s(line.substr(2));
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glm::vec3 v; s >> v.x; s >> v.y; s >> v.z;
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vertices.push_back(v);
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} else if (line.substr(0,2) == "f ") {
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std::istringstream s(line.substr(2));
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GLushort a,b,c;
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s >> a; s >> b; s >> c;
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a--; b--; c--;
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elements.push_back(a); elements.push_back(b); elements.push_back(c);
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} else if (line[0] == '#') { }
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else {}
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}
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normals.resize(vertices.size(), glm::vec3(0.0, 0.0, 0.0));
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for (int i = 0; i < elements.size(); i += 3) {
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GLushort ia = elements[i];
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GLushort ib = elements[i+1];
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GLushort ic = elements[i+2];
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glm::vec3 normal = glm::normalize(glm::cross(
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glm::vec3(vertices[ib]) - glm::vec3(vertices[ia]),
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glm::vec3(vertices[ic]) - glm::vec3(vertices[ia])));
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normals[ia] = normals[ib] = normals[ic] = normal;
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}
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logger << LOGGER_INFO << "Loaded OBJ: " << file << LOGGER_ENDL;
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}
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void FlatShade(std::vector<glm::vec3>& vertices, std::vector<glm::vec3>& normals, std::vector<GLushort>& elements) {
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std::vector<glm::vec3> shared_vertices;
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for (int i = 0; i < elements.size(); i++) {
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vertices.push_back(shared_vertices[elements[i]]);
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if ((i % 3) == 2) {
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GLushort ia = elements[i-2];
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GLushort ib = elements[i-1];
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GLushort ic = elements[i];
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glm::vec3 normal = glm::normalize(glm::cross(
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shared_vertices[ic] - shared_vertices[ia],
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shared_vertices[ib] - shared_vertices[ia]));
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for (int n = 0; n < 3; n++)
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normals.push_back(normal);
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}
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}
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}
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