Qt5 and OpenGL

[sajis997]

Hello forum,


I am having the following compilation error:

Model.cpp:233: error: 'glGenerateMipmap' was not declared in this scope
            glGenerateMipmap(GL_TEXTURE_2D);
                                          ^

Model.cpp:233: error: 'glGenerateMipmap' was not declared in this scope
            glGenerateMipmap(GL_TEXTURE_2D);
                                          ^

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I have a Model class with a member function to generate texture object.

GLint Model::TextureFromFile(const char* path, string directory, bool gamma)
        {
            //Generate texture ID and load texture data
           string filename = string(path);
           filename = directory + '/' + filename;
           GLuint textureID;
           glGenTextures(1, &textureID);
           int width,height;
           unsigned char* image = SOIL_load_image(filename.c_str(), &width, &height, 0, SOIL_LOAD_RGB);
           // Assign texture to ID
           glBindTexture(GL_TEXTURE_2D, textureID);
           glTexImage2D(GL_TEXTURE_2D, 0, gamma ? GL_SRGB : GL_RGB, width, height, 0, GL_RGB, GL_UNSIGNED_BYTE, image);
           glTexParameteri(GL_TEXTURE_2D,GL_GENERATE_MIPMAP,GL_TRUE);
 
            glGenerateMipmap(GL_TEXTURE_2D);
 
           // Parameters
           glTexParameteri( GL_TEXTURE_2D, GL_TEXTURE_WRAP_S, GL_REPEAT );
           glTexParameteri( GL_TEXTURE_2D, GL_TEXTURE_WRAP_T, GL_REPEAT );
           glTexParameteri( GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_LINEAR_MIPMAP_LINEAR );
           glTexParameteri( GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_LINEAR);
           glBindTexture(GL_TEXTURE_2D, 0);
           SOIL_free_image_data(image);
           return textureID;
        }

GLint Model::TextureFromFile(const char* path, string directory, bool gamma)
        {
            //Generate texture ID and load texture data
           string filename = string(path);
           filename = directory + '/' + filename;
           GLuint textureID;
           glGenTextures(1, &textureID);
           int width,height;
           unsigned char* image = SOIL_load_image(filename.c_str(), &width, &height, 0, SOIL_LOAD_RGB);
           // Assign texture to ID
           glBindTexture(GL_TEXTURE_2D, textureID);
           glTexImage2D(GL_TEXTURE_2D, 0, gamma ? GL_SRGB : GL_RGB, width, height, 0, GL_RGB, GL_UNSIGNED_BYTE, image);
           glTexParameteri(GL_TEXTURE_2D,GL_GENERATE_MIPMAP,GL_TRUE);

            glGenerateMipmap(GL_TEXTURE_2D);

           // Parameters
           glTexParameteri( GL_TEXTURE_2D, GL_TEXTURE_WRAP_S, GL_REPEAT );
           glTexParameteri( GL_TEXTURE_2D, GL_TEXTURE_WRAP_T, GL_REPEAT );
           glTexParameteri( GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_LINEAR_MIPMAP_LINEAR );
           glTexParameteri( GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_LINEAR);
           glBindTexture(GL_TEXTURE_2D, 0);
           SOIL_free_image_data(image);
           return textureID;
        }

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rest of the gl functions do not end up with the compilation error. Any idea ?

[d_stranz]

If you're compiling on Windows using Microsoft's OpenGL headers, then it looks like this function is not included in the core, but rather as an extension. See this stackoverflow post. You'll probably need to download and install glew or a similar extension library.