CS320      Lab5 - Transformations

Objectives:

• Understand the representation of a 3D object
• Experiment with transformations on that object

1. Download and Cube.java and try it out.
    
2. We will now modify the code to add translations along the x and y axes. 

   The following code can be used for key presses of the up, down, left, and right arrows.

   private class KeyResponder extends KeyAdapter
   {

       public void keyPressed(KeyEvent e){
           switch(e.getKeyCode()){
               case KeyEvent.VK_LEFT:
                   trans[0] = trans[0] - .5f;
                   break;
               case KeyEvent.VK_UP:
                   trans[1] = trans[1] + .5f;
                   break;
               case KeyEvent.VK_RIGHT:
                   trans[0] = trans[0] + .5f;
                   break;
               case KeyEvent.VK_DOWN:
                   trans[1] = trans[1] - .5f;
                   break;
           }
       }
   }
    

   Add the appropriate code so that when the arrow keys are pressed, our rotating box will be translated either up, down, right, or left.

   Just to see what will happen.  Try placing the translation code AFTER the code to do the rotation.
   This actually causes the translation to be performed BEFORE the rotation.  Why doesn't this work?
   Fix it so that it works now.
    

3. 
    

   Now add code so that the cube is scaled in all three dimensions by either .5 if you hit the 's' key or by 2.0 if you hit the 'S' key.  You want to scale about the origin so be sure that the scaling works with the translation.  Does this mean that the scaling needs to be done before or after the translation?  You figure it out. Hint:  In keyPressed you can add another switch that tests e.getKeyChar() so that you don't need the key codes for 's' and 'S'.

    

4. Email your completed Lab5 program to me.