1. Object Oriented Design

2. Goal  Homework #3 support  Q & A

3. Sequence of conditions matters!  Agents evaluate conditions from top to bottom.  If all conditions are true rule “fires” by executing all actions from top to bottom.  If a condition fails other conditions following it in the same rule will NOT be checked any longer  Example 1: onceEvery (), percentChance ()  Example 2: see (), key ().

4. This and that  Cars heading left and right versus roads with indicators  Use of depiction masks  Naming: avoid class specific names, e.g, “kill_frog” -> “kill”  Use depiction attributes instead of classes Frog class + deadFrog class => Frog with “alive” and “dead” depiction  What is connectivity u Example: roads

5. Semantics  Confusion about avoidance versus tracking Frogger: frogs hop onto logs they do not avoid logs

6. How to…  Make & control multiple counters u Example: Fractris  A continuous laser  Complex but passive background u Space invaders for cell phones

7. :Laser Recursive Sequence Diagrams : SpaceShip :Laser Key(space) Player fires laser new(below, laser) extend() [empty(below)] New (below, laser)