GLFW - hold window without using loop

Question

In order to hold the result open (the window screen) I have to do the following:

while (glfwGetWindowParam(GLFW_OPENED))
{
    // do some stuff
    glDrawPixels(...);
    glfwSwapBuffers();
}

But this loops through the body of the while loop until I stop it. I don't want to render in real time.

Does GLFW have an equivalent to the SDL_WaitEvent:

SDL_Surface* screen;
// do something with screen
SDL_Flip(screen);

SDL_Event event;
while (SDL_WaitEvent(&event))
{
   // handle input
}

If I try to do something like this, the program renders the result but after a while it stops responding:

//do stuff
glDrawPixels(...);
glfwSwapBuffers();

while (glfwGetWindowParam(GLFW_OPENED))
{
   if (glfwGetKey(GLFW_KEY_ESC) == GLFW_PRESS)
   {
       glfwTerminate();
   }
}

Answer 1

GLFW3 has a glfwWaitEvents that will probably do what you want.

http://www.glfw.org/docs/latest/group__window.html#ga554e37d781f0a997656c26b2c56c835e

Answer 2

Your typical GLFW main application loop should probably look something like this:

while (!glfwWindowShouldClose(window)) {
  glfwPollEvents();
  update();
  draw();
  glfwSwapBuffers(window);
}
glfwDestroyWindow(window);

Input can be handled via a callback such as the keyboard input callback. I use a wrapper class to handle my GLFW stuff so after I create a window I do something like this:

glfwSetWindowUserPointer(window, this);
glfwSetKeyCallback(window, glfwKeyCallback);

And my keyboard callback looks like this:

void glfwKeyCallback(GLFWwindow* window, int key, int scancode, int action, int mods) {
  GlfwApp * instance = (GlfwApp *) glfwGetWindowUserPointer(window);
  instance->onKey(key, scancode, action, mods);
}

and the base class implementation of the onKey method looks like this:

void GlfwApp::onKey(int key, int scancode, int action, int mods) {
  if (GLFW_PRESS != action) {
    return;
  }
  switch (key) {
  case GLFW_KEY_ESCAPE:
    glfwSetWindowShouldClose(window, 1);
    return;
  }
}

You can see the whole class here and here .

Answer 3

Instead of using glfwGetWindowParam() I think you may want to look into using glfwWindowShouldClose(). It takes in a pointer to the GLFW window. Here's a link to the GLFW docs page that has glfwWindowShouldClose() http://www.glfw.org/docs/latest/group__window.html