OpenGL draws with lot of missing faces [closed] - c++

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I am trying make an OBJ loder program, but no matter how hard I try, it simply just does not work properly. There are several faces missing. I turned on the triangulate faces, and the Keep vertex order in Blender, but I can not make it work
.
Here is my OBJLoader code:
#include "OBJLoader.h"
void OBJLoader::Load(string file){
int lines = 0;
int indexsize = 0;
int offset = 0;
vector<string> datalines;
vector<vec3> position;
vector<vec3> normal;
vector<vec2> texturecoord;
bool progress[] = { false, false, false, false};
bool succes = IOManager::readFiletoLines(file, datalines, lines);
if (!succes){
char* tmp = "";
cin >> tmp;
exit(-1);
}
int facecount = 0;
string::size_type sz;
for (int i = 0; i < lines-1; i++){
string line = datalines[i];
if (line.at(0) == 'v'){
if (line.at(1) == ' '){
if (!progress[0]){
cout << "Loading positions..." << endl;
progress[0] = true;
}
offset = 2;
float x = stof(line.substr(offset), &sz);
offset += sz+1;
float y = stof(line.substr(offset), &sz);
offset += sz+1;
float z = stof(line.substr(offset), &sz);
position.push_back(vec3(x, y, z));
continue;
}
else if (line.at(1) == 't'){
if (!progress[1]){
cout << "Loading texture coordinates..." << endl;
progress[1] = true;
}
offset = 3;
float u = stof(line.substr(offset), &sz);
offset += sz+1;
float v = stof(line.substr(offset), &sz);
texturecoord.push_back(vec2(u, v));
continue;
}else if (line.at(1) == 'n'){
if (!progress[2]){
cout << "Loading normals..." << endl;
progress[2] = true;
}
offset = 3;
float x = stof(line.substr(offset), &sz);
offset += sz+1;
float y = stof(line.substr(offset), &sz);
offset += sz+1;
float z = stof(line.substr(offset), &sz);
normal.push_back(vec3(x, y, z));
cout << "a";
continue;
}
}else if (line.at(0) == 'f'){
if (!progress[3]){
cout << "Loading faces..." << endl;
data.resize(position.size());
progress[3] = true;
}
facecount++;
cout << facecount << endl;
Vertex vertex;
Vertex vertex2;
Vertex vertex3;
//First corner
offset = 2;
int pos1=stoi(line.substr(offset), &sz);
offset += sz+1;
int tex1=stoi(line.substr(offset), &sz);
offset += sz+1;
int norm1=stoi(line.substr(offset), &sz);
//Second corner
offset += sz+1;
int pos2 = stoi(line.substr(offset), &sz);
offset += sz + 1;
int tex2 = stoi(line.substr(offset), &sz);
offset += sz + 1;
int norm2 = stoi(line.substr(offset), &sz);
//Third corner
offset += sz+1;
int pos3 = stoi(line.substr(offset), &sz);
offset += sz + 1;
int tex3 = stoi(line.substr(offset), &sz);
offset += sz + 1;
int norm3 = stoi(line.substr(offset), &sz);
//put the values into the data vector
vertex.postion(position[pos1 - 1].x, position[pos1 - 1].y, position[pos1 - 1].z);
vertex.textureUV(texturecoord[tex1 - 1].x, texturecoord[tex1 - 1].y);
vertex.normal(normal[norm1 - 1].x, normal[norm1 - 1].y, normal[norm1 - 1].z);
vertex.colorRGBA(1, 1, 1, 1);
data[pos1 - 1] = vertex;
vertex2.postion(position[pos2 - 1].x, position[pos2 - 1].y, position[pos2 - 1].z);
vertex2.textureUV(texturecoord[tex2 - 1].x, texturecoord[tex2 - 1].y);
vertex2.normal(normal[norm2 - 1].x, normal[norm2 - 1].y, normal[norm2 - 1].z);
vertex2.colorRGBA(1, 1, 1, 1);
data[pos2 - 1] = vertex2;
vertex3.postion(position[pos3 - 1].x, position[pos3 - 1].y, position[pos3 - 1].z);
vertex3.textureUV(texturecoord[tex3 - 1].x, texturecoord[tex3 - 1].y);
vertex3.normal(normal[norm3 - 1].x, normal[norm3 - 1].y, normal[norm3 - 1].z);
vertex3.colorRGBA(1, 1, 1, 1);
data[pos3 - 1] = vertex3;
indexdata.push_back(pos1-1);
indexdata.push_back(pos2-1);
indexdata.push_back(pos3-1);
}
}
}
And this is my rendering function.
void Loader::Model(char* model,int texture){
if (!models[0]){
openGL.Load(model);
data = openGL.data;
indexdata = openGL.indexdata;
models[0] = true;
}
initeverything();
glBindBuffer(GL_ARRAY_BUFFER, vbo[1]);
glActiveTexture(GL_TEXTURE0);
glBindTexture(GL_TEXTURE_2D, texture);
glBufferData(GL_ARRAY_BUFFER, data.size()*sizeof(Vertex), &data.front() , GL_STATIC_DRAW);
glBufferData(GL_ELEMENT_ARRAY_BUFFER, data.size()*sizeof(int), &indexdata.front(), GL_STATIC_DRAW);
cout << data[0].pos.x << endl;
glEnableVertexArrayAttrib(vao, 0);
glEnableVertexArrayAttrib(vao, 1);
glEnableVertexArrayAttrib(vao, 2);
glVertexAttribPointer(0, 3, GL_FLOAT, false, sizeof(Vertex), (void*)offsetof(Vertex, pos));
glVertexAttribPointer(1, 4, GL_FLOAT, false, sizeof(Vertex), (void*)offsetof(Vertex, color));
glVertexAttribPointer(2, 2, GL_FLOAT, false, sizeof(Vertex), (void*)offsetof(Vertex, vertUV));
glDrawElementsBaseVertex(GL_TRIANGLES, openGL.indexdata.size()*sizeof(int), GL_UNSIGNED_INT, 0, 0);
glBindBuffer(GL_ARRAY_BUFFER, 0);
glBindVertexArray(0);
}
And this is the result:
And it also happens on a simple cube.
Yes. That supposed to be a cube.

Answer 1

If I had to guess, I'd say the "Keep Vertex Order" flag might be the issue. OpenGL normally culls faces that aren't CounterClockWise oriented, and based on the triangles which got culled (which appear, on the surface, to be every-other-face for the affected objects), it's likely that those triangles are having their vertices be drawn in ClockWise order.
You could, for simplicity's sake, simply tell OpenGL to not cull faces:
glDisable(GL_CULL_FACE);
But a better solution might be to make sure the winding order is consistent on all the faces of your object.