Examples:

1. Finite State Example: The Paddle:
• A-Button: to create a new random shooting ball
• B-Button: to destroy current moving ball
• Left-Trigger: trigger the left-side paddles
• Right-Trigger: trigger the right-side paddles
• The Paddle class:
  • Two states: Rest and PaddleReturning
  • Update() method test and call each explicitly
  • Rest: if trigger angle, then rotate the paddle and goto PaddleReturning
  • PaddleReturning: gradually return, if user has new input, maintain the paddle rotation if necessary
• Record hit/miss for fun. Really? Not fun at all!

 

2. Abstract Paddle -- Almost free Left/Right paddles:
• The Paddle class: now abstract
• Left and Right subclasses, only differences is in resting/rotation values

 

3. The PaddleSet:
• The PaddleSet class: some simple parameterization
• Suddenly, we can create any number of paddles in a set!!
• Have I convinced you that abstraction is important?

 

4. Simple Patrol:
   • A-Button: to add a new patrol (try adding 100 patrols!)
   • B-Button: to remove an existing patrol
   • Notice behavior of patrol:
     • appears random
     • moves in counter-clockwise order
     • speed is sort of random
   • Class to check out: PatrolObject
     • Update function: define a state service function for each state!!
     • RandomXXRegionPosition() functions: generate a random position in the XX region, where XX can be top/bottom-left/right.
     • ComputePositionAndVelocity(): Compute a new velocity (with 20% randomness) and use time (number of ticks) as condition for transition to the next state.
        
5. Random Patrol:
   • Identical to above, except,
   • Randomize next states, look it is relatively straightforward to determine what each state should transition to (localized in each individual state's service routine!).
   • Some randomness is kind of cool?

    

6. Smooth Transition Patrol:
   • Exactly the same as the above, except
   • We do not compute new Velocity direction in ComputePositionAndVelocity() anymore!!
   • Instead: during each update, we call ComputeNewDirection() to rotate gradually from FrontDirection towards the final target position.
   • Oh, the patrols are smaller and we assign a random color to each patrol

    

7. Patrol That Chases:
   • Notice: straightforward to add in a new state: just add in new service routine into Update()
   • Notice: "partial" keyword to split complex class into multiple files
   • All Hero related behaviord are in PatrolObject_HeroSupport.cs
   • All other service routines now check for Hero being near by (DetectHero()):

   • In DetectHero():

     • Compute distance to Hero
     • If sufficiently close: transit to ChaseHero state!
   • Hero state service:
     • Always try to follow the hero (by setting mTargetPosition to hero.Center)
     • If cannot catch hero in specific time (mStateTimer), transition back into regular state by determining which quadrant the patrol is currently in. 
   • The app removes patrol if there is a collision with hero.