Change flag if mousepress while on loop

Question

I have this program that starts a loop when the key is pressed

The problem is that when i start the loop, i want to be able to stop it halfway with my mousepress.

The problem is that it doesn't register my mousepress until my loop is done.

How do I stop it halfway if the mouse was pressed in my loop? I tried a flag, if(mousePressed) but the flag doesnt change until the loop is done

Answer 1

You have to register the function that handles the callback function to be executed when a button is mouse pressed during your display() loop. This has to be done before running the main loop, when you are initialising everything that GLUT requires.

glutMouseFunc (MouseButton); 

Then you need to define the callback function itself, for example, something like this.

void MouseButton(int button, int state, int x, int y)
{
  // Respond to mouse button presses.
  // If button1 pressed, mark this state 

  if (button == GLUT_LEFT_BUTTON)
    {
      g_bButton1Down = (state == GLUT_DOWN) ? TRUE : FALSE;
    }
}

Note that g_bButton1Down is the global variable that you have to check to see if the mouse button is being pressed or not inside your main display() GLUT loop.

Take a loop at the glutMouseFunc specifications.