131 lines
3.0 KiB
C++
131 lines
3.0 KiB
C++
#ifndef MTLREADER_H
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#define MTLREADER_H
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#include <vector>
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#include <unordered_map>
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#include <string>
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#include <fstream>
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#include "../../../geo/Point2.h"
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#include "../../../geo/Point3.h"
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/**
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* prase .mtl files
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*/
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class MTLReader {
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public:
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struct Material {
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std::string textureFile = "";
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Point3 diffuse = Point3(1,1,1);
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float alpha = 1.0;
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};
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Material* cur = nullptr;
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std::unordered_map<std::string, Material> map;
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/** ctor. use readXYZ() */
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MTLReader() {
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;
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}
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/** read .obj from the given file */
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void readFile(const std::string& file) {
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std::ifstream is(file);
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std::string line;
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while(getline(is, line)) {parseLine(line);}
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is.close();
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}
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/** read obj from the given data string (.obj file contents) */
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void readData(const std::string& data) {
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std::stringstream is(data);
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std::string line;
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while(getline(is, line)) {parseLine(line);}
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}
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/** get the given material */
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const Material& getMaterial(const std::string& mat) const {
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const auto& it = map.find(mat);
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if (it == map.end()) {throw Exception("material not available");}
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return it->second;
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}
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private:
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template<typename Out>
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void split(const std::string &s, char delim, Out result) {
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std::stringstream ss(s);
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std::string item;
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while (std::getline(ss, item, delim)) {
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*(result++) = item;
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}
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}
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void replaceAll(std::string& str, const std::string& from, const std::string& to) {
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size_t start_pos = 0;
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while((start_pos = str.find(from, start_pos)) != std::string::npos) {
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size_t end_pos = start_pos + from.length();
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str.replace(start_pos, end_pos, to);
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start_pos += to.length(); // In case 'to' contains 'from', like replacing 'x' with 'yx'
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}
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}
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/** remove empty strings from the vector */
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std::vector<std::string> nonEmpty(const std::vector<std::string>& src) {
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std::vector<std::string> res;
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for (const std::string& s : src) {
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if (!s.empty()) {res.push_back(s);}
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}
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return res;
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}
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std::vector<std::string> split(const std::string &s, char delim) {
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std::vector<std::string> elems;
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split(s, delim, std::back_inserter(elems));
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return elems;
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}
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/** parse one line of the .obj file */
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void parseLine(std::string line) {
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if (line.length() < 2) {return;}
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// remove leading "#"
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while (line[0] == ' ' || line[0] == '\t') {
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line.erase(line.begin());
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}
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// remove other linebreaks
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replaceAll(line, "\r", "");
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const std::vector<std::string> tokens = nonEmpty(split(line, ' '));
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const std::string token = tokens.front();
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if ("newmtl" == token) {
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const std::string id = tokens[1];
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map[id] = Material();
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cur = &map[id];
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} else if ("map_Ka" == token) {
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const std::string texFile = tokens[1];
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cur->textureFile = texFile;
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} else if ("map_Kd" == token) {
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const std::string texFile = tokens[1];
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cur->textureFile = texFile;
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} else if ("Kd" == token) {
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cur->diffuse.x = std::stof(tokens[1]);
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cur->diffuse.y = std::stof(tokens[2]);
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cur->diffuse.z = std::stof(tokens[3]);
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} else if ("d" == token) {
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cur->alpha = std::stof(tokens[1]);
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}
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}
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};
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#endif // MTLREADER_H
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