呈現在OpenGL obj文件結束了丟失的頂點

Question

我通過修改一些代碼，我發現網上創建了一個.OBJ裝載機，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; 
} 

我然後用它畫

<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(); 
} 

這工作正常此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 

但是當我移動到更復雜的東西，喜歡一個人，我從一個免費模式的網站了作爲測試平臺的低多邊形模型，它缺少一個三角形，每一張臉（見下截圖）

魔方：

人形

男人在攪拌機中呈現罰款，所以它必須是我如何解析文件？

Answer 1

您需要在將模型導出爲格式時在攪拌機中對三角形進行三角測量。對於obj模型，您始終使用附加的法線進行導出，並對頂點進行三角化。您可能還需要檢查「保持頂點順序」。