呈现在OpenGL obj文件结束了丢失的顶点

Question

我通过修改一些代码，我发现网上创建了一个.OBJ装载机，解析到obj文件我下面

int mesh::getMesh(char* inputFile, std::vector<std::vector<glm::vec3>> & out_vertices,std::vector <glm::vec2> & out_uvs,std::vector <glm::vec3> & out_normals){ 
    std::cout << "Attempting to load file as model " << inputFile << "\n"; 

    std::vector<std::vector<unsigned int>> vertexIndices, uvIndices, normalIndices; 
    std::vector<glm::vec3> temp_vertices; 
    std::vector<glm::vec2> temp_uvs; 
    std::vector<glm::vec3> temp_normals; 

    FILE * file = fopen(inputFile, "r"); 
    if(file == NULL){ 
     std::cout << "Impossible to open the file !\n"; 
     return 0; 
    } 
    while(1){ 
     char lineHeader[128]; 
     // read the first word of the line 
     int res = fscanf(file, "%s", lineHeader); 
     if (res == EOF) 
      break; // EOF = End Of File. Quit the loop. 

     if (strcmp(lineHeader, "v") == 0){ 
      glm::vec3 vertex; 
      fscanf(file, "%f %f %f\n", &vertex.x, &vertex.y, &vertex.z); 
      temp_vertices.push_back(vertex); 
     }else if (strcmp(lineHeader, "vt") == 0){ 
      glm::vec2 uv; 
      fscanf(file, "%f %f\n", &uv.x, &uv.y); 
      temp_uvs.push_back(uv); 
     }else if (strcmp(lineHeader, "vn") == 0){ 
      glm::vec3 normal; 
      fscanf(file, "%f %f %f\n", &normal.x, &normal.y, &normal.z); 
      temp_normals.push_back(normal); 
     }else if (strcmp(lineHeader, "f") == 0){ 
      unsigned int vertexIndex[3], uvIndex[3], normalIndex[3]; 
      int matches = fscanf(file, "%d/%d/%d %d/%d/%d %d/%d/%d\n", &vertexIndex[0], &uvIndex[0], &normalIndex[0], &vertexIndex[1], &uvIndex[1], &normalIndex[1], &vertexIndex[2], &uvIndex[2], &normalIndex[2]); 
      if (matches != 9){ 
       std::cout << "File can't be read by the parser : (Try exporting with other options)\n"; 
       return 0; 
      } 

      std::vector<unsigned int> vertexTriangle; 
      vertexTriangle.push_back(vertexIndex[0]); 
      vertexTriangle.push_back(vertexIndex[1]); 
      vertexTriangle.push_back(vertexIndex[2]); 
      vertexIndices.push_back(vertexTriangle); 

      //uvIndices .push_back(uvIndex[0]); 
      //uvIndices .push_back(uvIndex[1]); 
      //uvIndices .push_back(uvIndex[2]); 

      //std::vector<unsigned int> normalTriangle; 
      //normalTriangle.push_back(normalIndex[0]); 
      //normalTriangle.push_back(normalIndex[1]); 
      //normalTriangle.push_back(normalIndex[2]); 
      //normalIndices.push_back(normalTriangle); 
     } 
    } 
    for(unsigned int i=0; i<vertexIndices.size(); i++){ 
     std::vector<unsigned int> vertexIndexs=vertexIndices[i]; 

     //glm::vec3 vertex0 = temp_vertices[ vertexIndexs[3]-1 ]; 
     glm::vec3 vertex1 = temp_vertices[ vertexIndexs[0]-1 ]; 
     glm::vec3 vertex2 = temp_vertices[ vertexIndexs[1]-1 ]; 
     glm::vec3 vertex3 = temp_vertices[ vertexIndexs[2]-1 ]; 
     std::vector<glm::vec3> vertex; 
     vertex.push_back(vertex1); vertex.push_back(vertex2); vertex.push_back(vertex3); 
     out_vertices.push_back(vertex); 

    } 
    return 1; 
} 

我然后用它画

<initialization...> 

std::vector<std::vector<glm::vec3>> vertices; 
std::vector<glm::vec2> uvs; 
std::vector<glm::vec3> normals; 

mesh::getMesh("Resources/Models/cube.obj",vertices,uvs,normals); 

<window handling and whatnot...> 

for (unsigned i=0; i < vertices.size(); i++) { 
    std::vector<glm::vec3> vertexGroup = vertices[i]; 
    glBegin(GL_TRIANGLES); 
     glVertex3f(vertexGroup[0].x,vertexGroup[0].y,vertexGroup[0].z); 
     glVertex3f(vertexGroup[1].x,vertexGroup[1].y,vertexGroup[1].z); 
     glVertex3f(vertexGroup[2].x,vertexGroup[2].y,vertexGroup[2].z); 
    glEnd(); 
} 

这工作正常此obj文件

# Blender3D v249 OBJ File: untitled.blend 
# www.blender3d.org 
mtllib cube.mtl 
v 1.000000 -1.000000 -1.000000 
v 1.000000 -1.000000 1.000000 
v -1.000000 -1.000000 1.000000 
v -1.000000 -1.000000 -1.000000 
v 1.000000 1.000000 -1.000000 
v 0.999999 1.000000 1.000001 
v -1.000000 1.000000 1.000000 
v -1.000000 1.000000 -1.000000 
vt 0.748573 0.750412 
vt 0.749279 0.501284 
vt 0.999110 0.501077 
vt 0.999455 0.750380 
vt 0.250471 0.500702 
vt 0.249682 0.749677 
vt 0.001085 0.750380 
vt 0.001517 0.499994 
vt 0.499422 0.500239 
vt 0.500149 0.750166 
vt 0.748355 0.998230 
vt 0.500193 0.998728 
vt 0.498993 0.250415 
vt 0.748953 0.250920 
vn 0.000000 0.000000 -1.000000 
vn -1.000000 -0.000000 -0.000000 
vn -0.000000 -0.000000 1.000000 
vn -0.000001 0.000000 1.000000 
vn 1.000000 -0.000000 0.000000 
vn 1.000000 0.000000 0.000001 
vn 0.000000 1.000000 -0.000000 
vn -0.000000 -1.000000 0.000000 
usemtl Material_ray.png 
s off 
f 5/1/1 1/2/1 4/3/1 
f 5/1/1 4/3/1 8/4/1 
f 3/5/2 7/6/2 8/7/2 
f 3/5/2 8/7/2 4/8/2 
f 2/9/3 6/10/3 3/5/3 
f 6/10/4 7/6/4 3/5/4 
f 1/2/5 5/1/5 2/9/5 
f 5/1/6 6/10/6 2/9/6 
f 5/1/7 8/11/7 6/10/7 
f 8/11/7 7/12/7 6/10/7 
f 1/2/8 2/9/8 3/13/8 
f 1/2/8 3/13/8 4/14/8 

但是当我移动到更复杂的东西，喜欢一个人，我从一个免费模式的网站了作为测试平台的低多边形模型，它缺少一个三角形，每一张脸（见下截图）

魔方：

人形

男人在搅拌机中呈现罚款，所以它必须是我如何解析文件？

Answer 1

您需要在将模型导出为格式时在搅拌机中对三角形进行三角测量。对于obj模型，您始终使用附加的法线进行导出，并对顶点进行三角化。您可能还需要检查“保持顶点顺序”。