I am trying to load OBJ files to use them in OpenGL. Every object in the OBJ file has its own texture. In my code I split up every object of the file into a struct that is defended like this:
struct ObjModelComponent {
std::vector<glm::vec3> vertices;
std::vector<glm::vec2> uvs;
std::vector<glm::vec3> normals;
Texture tex;
ArrayBuffer vertex, uv, normal;
GLuint VAO;
};
The Texture class is a simple class to make loading and handling a texture easier.
In the class of the model I have a std::vector of my ObjModelComponent.
I'm rendering the Object like this:
void ObjModel::render() {
for(int i = 0; i < components.size(); i++) {
components[i].vertex.activate();
components[i].uv.activate();
components[i].normal.activate();
glActiveTexture(GL_TEXTURE0);
glBindTexture(GL_TEXTURE_2D, components[i].tex.getTextureID());
shader->sendInt(0, components[i].tex.getTextureName());
glBindVertexArray(components[i].VAO);
shader->sendMat4(*data->projection, "projection");
shader->sendMat4(data->viewMat, "view");
shader->sendMat4(model, "model");
glDrawArrays(GL_TRIANGLES, 0, int(components[i].vertices.size()));
glBindVertexArray(0);
}
}
The Texture class looks like this:
Texture::Texture(std::string fileName, TextureType type):
textureName("tex"), fileName(fileName), type(type) {
glGenTextures(1, &tex);
glBindTexture(GL_TEXTURE_2D, tex);
unsigned char *image = SOIL_load_image(fileName.c_str(), &texWidth, &texHeight, 0, SOIL_LOAD_RGBA);
glTexImage2D(GL_TEXTURE_2D, 0, GL_RGBA, texWidth, texHeight, 0, GL_RGBA, GL_UNSIGNED_BYTE, image);
glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_S, GL_REPEAT);
glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_T, GL_REPEAT);
switch (type) {
case TEXTURE_GENERATE_MIPMAP:
glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_LINEAR_MIPMAP_NEAREST);
glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_LINEAR_MIPMAP_NEAREST);
glGenerateMipmap(GL_TEXTURE_2D);
break;
case TEXTURE_NO_MIP_MAP:
glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_LINEAR);
glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_LINEAR);
default:
glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_LINEAR);
glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_LINEAR);
break;
}
glBindTexture(GL_TEXTURE_2D, 0);
SOIL_free_image_data(image);
}
Texture::Texture() {
}
Texture& Texture::operator=(const Texture &other) {
this->fileName = other.fileName;
this->textureName = other.textureName;
this->type = other.type;
// glDeleteTextures(1, &tex);
glGenTextures(1, &tex);
glBindTexture(GL_TEXTURE_2D, tex);
unsigned char *image = SOIL_load_image(fileName.c_str(), &texWidth, &texHeight, 0, SOIL_LOAD_RGBA);
glTexImage2D(GL_TEXTURE_2D, 0, GL_RGBA, texWidth, texHeight, 0, GL_RGBA, GL_UNSIGNED_BYTE, image);
glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_S, GL_REPEAT);
glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_T, GL_REPEAT);
switch (type) {
case TEXTURE_GENERATE_MIPMAP:
glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_LINEAR_MIPMAP_NEAREST);
glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_LINEAR_MIPMAP_NEAREST);
glGenerateMipmap(GL_TEXTURE_2D);
break;
case TEXTURE_NO_MIP_MAP:
glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_LINEAR);
glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_LINEAR);
default:
glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_LINEAR);
glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_LINEAR);
break;
}
glBindTexture(GL_TEXTURE_2D, 0);
SOIL_free_image_data(image);
return *this;
}
Texture::~Texture() {
glDeleteTextures(1, &tex);
}
GLuint Texture::getTextureID() {
return tex;
}
void Texture::setTextureName(std::string name) {
textureName = name;
}
std::string Texture::getTextureName() {
return textureName;
}
glm::vec2 Texture::getTextureSize() {
return glm::vec2(texWidth, texHeight);
}
This is how the components are generated:
for(int i = 0; i < fileLines.size(); i++) {
if(fileLines[i].substr(0, 2) == "o ") {
if(!first) {
tmpComp.tex = tmpTex;
components.emplace_back(tmpComp);
componentIndex++;
}
first = false;
tmpTex = Texture(hg::substr(path, 0, int(path.find_last_of("/"))) + "/" + hg::substr(fileLines[i], 2, int(fileLines[i].length())) + ".png");
}
}
This is how the VAOs and array buffers are generated:
for(int i = 0; i < components.size(); i++) {
glGenVertexArrays(1, &components[i].VAO);
glBindVertexArray(components[i].VAO);
components[i].vertex.setData(components[i].vertices.data(), sizeof(glm::vec3) * components[i].vertices.size(), 0);
components[i].uv.setData(components[i].uvs.data(), sizeof(glm::vec2) * components[i].uvs.size(), 1);
components[i].normal.setData(components[i].normals.data(), sizeof(glm::vec3) * components[i].normals.size(), 2);
components[i].vertex.activate();
components[i].uv.activate();
components[i].normal.activate();
glBindVertexArray(0);
}
You can find my complete code on GitHub: https://github.com/Kuechenzwiebel/SDL-OpenGL-Tests
The problem is, that the texture displayed on my object is that, that was used by the last object that was rendered.
Update: Removing the glDeleteTextures in the destructor of the Texture, yields in the result, that the texture displayed on all components is that that was used for the last component.
I really don't understand why this isn't working, I copied it from other primitives, that only use one texture. And there everything is working fine.
I found a workaround, instead of having separate ArrayBuffers and VAOs, I only use one of each and also store at which index a new object begins. There I change the texture that is used.