window - game loop - render

//...
  // set the buffer clear color to red (rgba code)
  glClearColor(1.0, 0.0, 0.0, 1.0);
  // persist the window until user closes it
  while (!glfwWindowShouldClose(window))
  {
    // 'buffer' means an image which can be displayed on the screen
    // OpenGL has a 'front buffer' which is displayed on the screen and a 'back buffer'
    // which is used for drawing.

    // every tick, clear the front buffer and swap in the back buffer
    glClear(GL_COLOR_BUFFER_BIT);
    glfwSwapBuffers(window);
    // process pending events (for example, clicking the close button)
    glfwPollEvents();
  }
//...