Display 2D text with freeglut, using OpenGL

问题

I'm pretty new into this and I'd like to display fixed location 2D texts (like level, life, score etc.) on my game's screen which is basically a 3D game. I have found a few similar questions but still could not figure out the solution for me. I mainly use GLFW for everything but I'd like to use glut for displaying texts. I have a funcion (based on a few other questions I've found here) to try out how it works but I'm not sure how exactly can I make it to actually display because now everything starts but no text is displayed, only my 3D world.. Here is my code so far:

//includes...
//and other stuff...

void display()
{
    glMatrixMode(GL_PROJECTION);
    glPushMatrix();
    glLoadIdentity();
    gluOrtho2D(0.0, WindowWidth, 0.0, WindowHeight);

    glMatrixMode(GL_MODELVIEW);
    glPushMatrix();
    glLoadIdentity();

    glColor3f(0.0, 1.0, 0.0); // Green
    glRasterPos2i(20, 20);

    std::string s = "Some text";
    void* font = GLUT_BITMAP_9_BY_15;

    for (std::string::iterator i = s.begin(); i != s.end(); ++i)
    {
        char c = *i;
        glColor3d(1.0, 0.0, 0.0);
        glutBitmapCharacter(font, c);
    }

    glMatrixMode(GL_MODELVIEW);
    glPopMatrix();

    glMatrixMode(GL_PROJECTION);
    glPopMatrix();
}

int main(void)
{
    // init glfw and set some options...
    glfwInit();

    //also, it seems I need to init glut to use my function too which requires arguments...
    {
        int argc = 1;
        char* argv[1] = { (char*)"Something" };
        glutInit(&argc, argv);
    }

    //creating window...
    GLFWwindow* window = glfwCreateWindow(WindowWidth, WindowHeight, "The Maze Game", nullptr, nullptr);

    // QUESTION: should I call the function here or where the game loop is? It doesn't work either way.. :(
    display();

    while (!glfwWindowShouldClose(window)) {

        //doing stuff...

        glfwPollEvents();

        // I have to display text later HERE... where the std::couts are... would be better on screen instead of console..

        if(moved == true) timer = timer - delta;

        std::cout << timer << std::endl; 

        if (win == true || timer <= 0.f)
         {
            if (win == true)
            {
                score++;
            }
            if (timer <= 0.f && life > 0)
            {
                life--;
                if (life == 0)
                {
                    std::cout << "You LOST" << std::endl;
                }
            }
            //...stuff
            timer = mazeTime;
            win = false;
            std::cout << "Score: " << score << std::endl;
            std::cout << "Life: " << life << std::endl;
        }

        // Clear the colorbuffer
        glClearColor(0.0f, 0.0f, 0.0f, 1.0f);
        glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT);

        // etc....

来源：https://stackoverflow.com/questions/61341652/display-2d-text-with-freeglut-using-opengl