Build Your Game: Vector Actors and Particles - Beginning iOS6 Games Development - page 168

each is implemented with the same base class, Particle . Let's take a closer look at the class
Example03Controller to better understand how this example works before diving into the details of
each new actor. Listing 7-14, shows the important parts of Example03Controller .
Listing 7-14. Example03Controller.m (doSetup and updateScene)
-(BOOL)doSetup{
if([super doSetup]){
NSMutableArray* classes = [NSMutableArray new];
[classes addObject:[Asteroid class]];
[self setSortedActorClasses:classes];
UITapGestureRecognizer* tapRecognizer = [[UITapGestureRecognizer alloc]
initWithTarget:self action:@selector(tapGesture:)];
[tapRecognizer setNumberOfTapsRequired:1];
[tapRecognizer setNumberOfTouchesRequired:1];
[actorsView addGestureRecognizer:tapRecognizer];
return YES;
}
return NO;
}
-(void)updateScene{
if (self.stepNumber % (60*5) == 0){
[self addActor:[Comet comet:self]];
}
if ([[self actorsOfType:[Asteroid class]] count] == 0){
int count = arc4random()%4+1;
for (int i=0;i<count;i++){
[self addActor:[Asteroid asteroid:self]];
}
}
[super updateScene];
}
In Listing 7-14, we see two tasks of the class Example03Controller : doSetup and updateScene .
The task doSetup follows our now familiar pattern of identifying the actor classes we want efficient
access to—in this case, Asteroid , by calling the task setSortedActorClass: . We also create a
UITapGestureRecognizer called tapRecognizer and register that with the actorsView object. In this
way, the task tapGesture: will be called when we tap the screen.
The task updateScene , as shown in Listing 7-14, adds a new Comet actor every five seconds (60*5)
and adds one to four Asteroids whenever there are zero Asteroids in the scene. As with the previous
examples, the code in the controller class is relatively simple. Most of the real logic for the example
lives in the different actor classes. Before we look at the Asteroid class, let's consider the task
tapGesture: , shown in Listing 7-15.