Generated window with GLFW, background color not changing-CodePudding

I'm trying to change the background color in a window generated by OpenGL/GLFW and I'm using a similar code than the one in the GLFW docs. I'm on Ubuntu 20.04 and the window background is always black, no matter the parameters in the glClearColor() function.

I tried this on Windows 10 using VS and it worked perfectly, but on Ubuntu it's not working at all. No error messages are generated.

I also followed The Cherno's Sparky game engine series, and tried encapsulating the glClear() function in a class method, but this didn't change anything.

This is the whole code:

#include <iostream>
#include <GL/gl.h>
#include <GLFW/glfw3.h>

int main(int argc, char *argv[])
{
    std::cout << "Hello world!" << std::endl;
    if (!glfwInit())
    {
        // Initialization failed
        exit(EXIT_FAILURE);
    }

    GLFWwindow* window = glfwCreateWindow(640, 480, "My Title", NULL, NULL);
    if (!window)
    {
        // Window or OpenGL context creation failed
        std::cout << "Error creating window!" << std::endl;
        glfwTerminate();
        exit(EXIT_FAILURE);
    }

    glfwMakeContextCurrent(window);
    glfwSwapInterval(1);

    glClearColor(1.0f, 0.0f, 0.0f, 1.0f);

    while (!glfwWindowShouldClose(window)) 
    {
        int width, height;

        glfwGetFramebufferSize(window, &width, &height);

        glViewport(0, 0, width, height);
        glClear(GL_COLOR_BUFFER_BIT);



        glfwSwapBuffers(window);
        glfwPollEvents();
    }

    glfwDestroyWindow(window);

    glfwTerminate();
    exit(EXIT_SUCCESS);

    return 0;
}

I'm supposed to get a window with a red background but it's black.

As additional elements, I'm also using CMake to help configuring and building the project (quite overkill I know), and I believe clang is the compiler used for the project. Maybe that influences the result.

CodePudding user response：

You need an appropriate loader after glfwMakeContextCurrent(window).

If you are using glad, you should call gladLoadGL(glfwGetProcAddress) after glfwMakeContextCurrent(window) as the official doc suggests here.