Precept 7 More about assignment 3

• what to do when a shape ends up outside the viewport in the next time step?
  You have to detect this, and can then just put the shape inside the viewport, at the edge. This is not physically correct, but it'll do. In general you don't have to worry about "awkward" cases (e.g. three shapes colliding at the same time)
• how to do animation?
  Take a look at example 4, in /u/cs426/Examples/Tcl+OpenGL/ex4, Tcl script filename ex4:
  

  proc Animate {} {
    global myGLWin
  
    ex4:rotate;
    $myGLWin swapbuffers;
    after 150 Animate;
  };
         

  The after command invokes the procedure again after 150 milliseconds in this example
• we've found this great vector/matrix package: can we use everything?
  You can use everything, except for the functions that actually create the matrices for translation/rotation etc. (this is just to make you code it once in your life :-)