GLAD link is not providing needed functions

Question

TLDR: The GLAD header file won't let me use the openGL Commands and I don't know exactly why.

Here's a breakdown:

I'm on a Windows 10 Laptop.
I'm coding in C++.
I'm compiling with MinGW's g++ tool.
I'm using GLFW and GLAD.

My file layout is something like this:

OpenGLTest
    include
        glad
            glad.h
        GLFW
            glfw3.h
            glfw3native.h
        KHR
            khrplatform.h
    glad.c
    glfw3.dll
    GraphicsTest.cpp(Main File)
    libglfw3dll.a(I have forgotten what this does, it's a remnant from older attempts at openGL. Relevant?)
    Makefile(a single command: "g++ GraphicsTest.cpp -g -L glad.c glfw3.dll")

As far as I can tell, the program will compile and run flawlessly if any and all commands from GLAD and openGL are commented out. All it then does is make a small window.
If said lines are not commented out, the compiler will throw a slew of errors, all following this form:
```
D:\Documents\Programming\C++\Programs\OpenGLTest/GraphicsTest.cpp:23: undefined reference to `gladLoadGL'
```
...with gladLoadGL being replaced with the relevant function.

The file itself reads thusly:

#include<iostream>
#include<glad\glad.h>
#include<GLFW\glfw3.h>

static void whatIsGoingOnSeriouslyGuysHelp(int id,const char* desc)
{
    std::cout<<desc;
}
int main()
{
    glfwSetErrorCallback(&whatIsGoingOnSeriouslyGuysHelp);
    glfwInit();
    glfwWindowHint(GLFW_CONTEXT_VERSION_MAJOR, 3);
    glfwWindowHint(GLFW_CONTEXT_VERSION_MINOR, 3);
    glfwWindowHint(GLFW_OPENGL_PROFILE, GLFW_OPENGL_CORE_PROFILE);

    GLFWwindow* window = glfwCreateWindow(100,100,"TEST",NULL,NULL);
    if (window == NULL)
    {
        std::cout<<"Window Creation Error";
    }
    glfwMakeContextCurrent(window);
    gladLoadGL();
    //glViewport(0,0,100,100);

    while (!glfwWindowShouldClose(window))
    {
        //std::cout<<"?";
        glfwPollEvents();
        glfwSwapBuffers(window);
        //glClearColor(0.2f, 0.3f, 0.3f, 1.0f);
        //glClear(GL_COLOR_BUFFER_BIT);
    }
    glfwDestroyWindow(window);
    glfwTerminate();
    return 0;
}

I have tried re-installing GLAD, but that didn't do anything. I haven't tried re-installing GLFW, but I don't think that's the problem.

Correct any misconceptions I have or errors I am making.

What GLAD generator parameters were used? Check the comment block at the top of `glad.h` under `Commandline:` and `Online:`. — genpfault, Feb 17 '23 at 15:15

score 2 · Accepted Answer · answered Feb 17 '23 at 09:17

2

You need to include glad.c in your compile command as follows: (you had a -L before it which tells gcc to treat glad.c as a directory for libraries)

g++ GraphicsTest.cpp glad.c -g glfw3.dll

, and instead of gladLoadGL, you should use the GLFW loader:

    if (!gladLoadGLLoader((GLADloadproc) glfwGetProcAddress)) {
        std::cout << "Failed to initialize OpenGL context" << std::endl;
        return -1;
    }

Finally, you should invest a tiny bit of time into a decent build system because compiling every file every time will get real slow real fast. Here is the absolute minimal Makefile to get you started:

graphicstest: graphicstest.o glad.o
  g++ -g -o $@ $^ glfw3.dll

answered Feb 17 '23 at 09:17

Botje

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Thanks! The first bit solved the problem and I'll be sure to implement the second. About the third, though...I don't fully understand. I am using a makefile, as mentioned, but is the method you were showing a better one than mine? How so? Where should I go to learn more about this topic? – Sad Robot Mar 01 '23 at 23:23
My makefile compiles each c file independently, and only if the file has changed. Yours will compile glad.c from scratch every time. And it gets worse the more files you add. – Botje Mar 01 '23 at 23:44

GLAD link is not providing needed functions

1 Answers1