A Completed Game: Belt Commander - Beginning iOS6 Games Development - page 289

Listing 12-18. Viper.h
enum{
VPR_STATE_STOPPED = 0,
VPR_STATE_UP,
VPR_STATE_DOWN,
VPR_STATE_COUNT
};
@interface Viper : Actor <ImageRepresentationDelegate, LinearMotionDelegate>{
LinearMotion* motion;
long lastStepDamageWasModified;
}
@property (nonatomic) float health;
@property (nonatomic) float maxHealth;
@property (nonatomic) long lastShot;
@property (nonatomic) long stepsPerShot;
@property (nonatomic) BOOL shootTop;
@property (nonatomic) int damage;
+(id)viper:(GameController*)gameController;
-(void)setMoveToPoint:(CGPoint)aPoint within:(GameController*)gameController;
-(void)incrementHealth:(float)amount;
-(void)decrementHealth:(float)amount;
-(void)incrementDamage:(GameController*)gameController;
-(void)decrementDamage:(GameController*)gameController;
@end
In Listing 12-18, we see the header file for the class Viper . In this file, we see that we define an enum
with three states. This is very much like the enums we have declared in the past to specify the state
of an Actor . Looking at the properties, we can see that we have a property for health and maxHealth .
We also have a property called lastShot , which will be used to keep track of whether it is time to
shoot another Bullet in conjunction with the property stepsPerShot . The BOOL property shootTop is
used to keep track if the next Bullet should come from the top of the Viper or not. The last property
damage indicates the damage value of the next Bullet .
The tasks in Listing 12-18 are pretty mundane. There are four tasks for incrementing and
decrementing heal t h and damage . Each keeps the value of health and damage within a reasonable
range. The interesting task is setMoveToPoint:within: , as shown in Listing 12-19.
Listing 12-19. Viper.m (setMoveToPoint:within:)
-(void)setMoveToPoint:(CGPoint)aPoint within:(GameController*)gameController{
if (motion){
[[self behaviors] removeObject: motion];
}
CGPoint point = CGPointMake([self center].x, aPoint.y);