shader2/model.cpp

#include "model.h"
#include "misc.h"
#include <stdio.h>
#include <string>
#include <sstream>
#include <vector>

VertexData * LoadObjModel(const char * filePath, unsigned int ** indexes, int & vertexCount, int & indexCount)
{
	char* fileContent = LoadFileContent(filePath);
	if (fileContent != nullptr) {
		
		struct VertexInfo {
			float v[3];
		};

		struct VertexDefine {
			int positionIndex;
			int texcoordIndex;
			int normalIndex;
		};

		std::vector<VertexInfo> position;
		std::vector<VertexInfo> texcoord;
		std::vector<VertexInfo> normal;
		
		std::vector<unsigned int> objIndexes; //点的索引 对应opengl的indexes
		std::vector<VertexDefine> vertices; //每一个点 对应opengl的vertex

		std::stringstream ssObjFile(fileContent);
		char szOneLine[256];
		std::string temp;
		while (!ssObjFile.eof()) {
			memset(szOneLine, 0, 256);
			ssObjFile.getline(szOneLine, 256);
			//printf("%s \n", szOneLine);
			if (strlen(szOneLine) > 0) {
				std::stringstream ssOneLine(szOneLine);
				if (szOneLine[0] == 'v') {
					if (szOneLine[1] == 't') {
						ssOneLine >> temp;
						VertexInfo vi;
						ssOneLine >> vi.v[0];
						ssOneLine >> vi.v[1];
						texcoord.push_back(vi);
					}
					else if (szOneLine[1] == 'n') {
						ssOneLine >> temp;
						VertexInfo vi;
						ssOneLine >> vi.v[0];
						ssOneLine >> vi.v[1];
						ssOneLine >> vi.v[2];
						normal.push_back(vi);
					}
					else {
						ssOneLine >> temp;
						VertexInfo vi;
						ssOneLine >> vi.v[0];
						ssOneLine >> vi.v[1];
						ssOneLine >> vi.v[2];

						position.push_back(vi);
					}
				}
				else if(szOneLine[0] == 'f'){
					ssOneLine >> temp;
					std::string vertexStr;
					for (int i = 0; i < 3; i++) {
						ssOneLine >> vertexStr;

						size_t pos = vertexStr.find_first_of('/');
						std::string positionIndexStr = vertexStr.substr(0, pos);
						size_t pos2 = vertexStr.find_first_of('/', pos + 1);
						std::string texcoordIndexStr = vertexStr.substr(pos + 1, pos2 - pos - 1);
						std::string normalIndexStr = vertexStr.substr(pos2 + 1, vertexStr.length() - pos2 - 1);

						VertexDefine vd;
						vd.positionIndex = atoi(positionIndexStr.c_str()) - 1;
						vd.texcoordIndex = atoi(texcoordIndexStr.c_str()) - 1;
						vd.normalIndex = atoi(normalIndexStr.c_str()) - 1;

						int nCurrentIndex = -1;
						size_t nCurrentVerticeCount = vertices.size();
						for (size_t j = 0; j < nCurrentVerticeCount; j++) {
							if (vertices[j].positionIndex == vd.positionIndex &&
								vertices[j].texcoordIndex == vd.texcoordIndex &&
								vertices[j].normalIndex == vd.normalIndex) {
								nCurrentIndex = j;
								break;
							}
						}

						if (nCurrentIndex == -1) {
							nCurrentIndex = vertices.size();
							vertices.push_back(vd);
						}

						objIndexes.push_back(nCurrentIndex);

					}
				}
			}
		}
		printf("face count %u\n", objIndexes.size() / 3);

		indexCount = (int)objIndexes.size();
		*indexes = new unsigned int[indexCount];
		for (int i = 0; i < indexCount; i++) {
			(*indexes)[i] = objIndexes[i];
		}

		vertexCount = (int)vertices.size();
		VertexData *vertexes = new VertexData[vertexCount];
		for (int i = 0; i < vertexCount; i++) {
			memcpy(vertexes[i].position, position[vertices[i].positionIndex].v, sizeof(float) * 3);
			memcpy(vertexes[i].texcoord, texcoord[vertices[i].texcoordIndex].v, sizeof(float) * 2);
			memcpy(vertexes[i].normal, normal[vertices[i].normalIndex].v, sizeof(float) * 3);
		}
		return vertexes;
	}
	return nullptr;
}