title: How to draw while resizing GLFW window?
body: <p>Whenever I resize a GLFW window it doesn't draw while I'm resizing the window. The newly exposed part of the window only gets drawn on after I finish resizing the window. You can see it for yourself in the picture below:</p>
  
  <p><img src="https://i.stack.imgur.com/e2pvd.png" alt="image"></p>
  
  <p>Here is the code for my application. I am running Windows 10 on Visual Studio 2015   </p>
  
  <pre><code>#include &lt;glad/glad.h&gt;
  #include &lt;GLFW/glfw3.h&gt;
  #include &lt;iostream&gt;
  
  void framebuffer_size_callback(GLFWwindow* window, int width, int height);
  void processInput(GLFWwindow *window);
  void get_resolution(int* window_width, int* window_height);
  void initGlfwSettings();
  GLFWwindow* initGlfwWindow();
  void initGlad();
  
  // settings
  const unsigned int SCR_WIDTH = 800;
  const unsigned int SCR_HEIGHT = 600;
  
  int main()
  {
      initGlfwSettings();
  
      GLFWwindow* window = initGlfwWindow();
  
      initGlad();
  
      // glad: load all OpenGL function pointers
      // ---------------------------------------
  
  
      // render loop
      // -----------
      while (!glfwWindowShouldClose(window))
      {
          int width, height;
          glfwGetWindowSize(window, &amp;width, &amp;height);
  
  
          glClearColor(0.2f, 0.3f, 0.3f, 1.0f);
          glClear(GL_COLOR_BUFFER_BIT);
  
          glfwSetFramebufferSizeCallback(window, framebuffer_size_callback);
          // input
          // -----
          processInput(window);
  
          // glfw: swap buffers and poll IO events (keys pressed/released, mouse moved etc.)
          // -------------------------------------------------------------------------------
          glfwSwapBuffers(window);
          glfwPollEvents();
      }
  
      // glfw: terminate, clearing all previously allocated GLFW resources.
      // ------------------------------------------------------------------
      glfwTerminate();
      return 0;
  }
  
  // process all input: query GLFW whether relevant keys are pressed/released this frame and react accordingly
  // ---------------------------------------------------------------------------------------------------------
  void processInput(GLFWwindow *window)
  {
      if (glfwGetKey(window, GLFW_KEY_ESCAPE) == GLFW_PRESS)
          glfwSetWindowShouldClose(window, true);
  }
  
  // glfw: whenever the window size changed (by OS or user resize) this callback function executes
  // ---------------------------------------------------------------------------------------------
  void framebuffer_size_callback(GLFWwindow* window, int width, int height)
  {
      // make sure the viewport matches the new window dimensions; note that width and 
      // height will be significantly larger than specified on retina displays.
      glViewport(0, 0, width, height);
  }
  
  void get_resolution(int* window_width, int* window_height) {
      const GLFWvidmode * mode = glfwGetVideoMode(glfwGetPrimaryMonitor());
  
      *window_width = mode-&gt;width;
      *window_height = mode-&gt;height;
  }
  
  void initGlfwSettings()
  {
      // glfw: initialize and configure
      // ------------------------------
      glfwInit();
      glfwWindowHint(GLFW_CONTEXT_VERSION_MAJOR, 3);
      glfwWindowHint(GLFW_CONTEXT_VERSION_MINOR, 3);
      glfwWindowHint(GLFW_OPENGL_PROFILE, GLFW_OPENGL_CORE_PROFILE);
  
  
      #ifdef __APPLE__
          glfwWindowHint(GLFW_OPENGL_FORWARD_COMPAT, GL_TRUE); // uncomment this statement to fix compilation on OS X
      #endif
  }
  
  GLFWwindow* initGlfwWindow()
  {
      /*GLFWmonitor* monitor = glfwGetPrimaryMonitor();
      int width;
      int height;
  
      get_resolution(&amp;width, &amp;height);*/
  
  
  
      GLFWwindow* window = glfwCreateWindow(SCR_WIDTH, SCR_HEIGHT, "learning opengl", NULL, NULL);
      if (window == NULL)
      {
          std::cout &lt;&lt; "Failed to create GLFW window" &lt;&lt; std::endl;
          glfwTerminate();
          exit(1);
      }
  
      glfwMakeContextCurrent(window);
      glfwSetFramebufferSizeCallback(window, framebuffer_size_callback);
      glfwSwapInterval(1);
  
      return window;
  }
  
  void initGlad()
  {
      if (!gladLoadGLLoader((GLADloadproc)glfwGetProcAddress))
      {
          std::cout &lt;&lt; "Failed to initialize GLAD" &lt;&lt; std::endl;
          exit(1);
      }
  }
  </code></pre>
  
  <p>Explain any solutions to this problem.</p>