Book Image

Sparrow iOS Game Framework Beginner's Guide

By : Johannes Stein
Book Image

Sparrow iOS Game Framework Beginner's Guide

By: Johannes Stein

Overview of this book

Table of Contents (20 chapters)
Sparrow iOS Game Framework Beginner's Guide
About the Author
About the Reviewers

Time for action – letting cannonballs collide with ships

To check if cannonballs collide against the enemy ship, follow these steps:

  1. Open the Ship.h file.

  2. We need to add custom getters and setters to the hitpoints property, so let's make this property nonatomic and add an instance variable called _hitpoints.

  3. Declare the methods abortShooting and hit.

  4. Switch to the Ship.m file.

  5. The custom hitpoints getter just returns the instance variable _hitpoints.

  6. The custom setter for hitpoints contains the following code:

    -(void) setHitpoints:(int)hitpoints
        _hitpoints = hitpoints;
        if (_hitpoints <= 0) {
            self.visible = NO;
  7. The abortShooting method consists of the following lines:

    -(void) abortShooting
        _isShooting = NO;
        [Sparrow.juggler removeObjectsWithTarget:self.cannonBallLeft];
        [Sparrow.juggler removeObjectsWithTarget:self.cannonBallRight];
        self.cannonBallLeft.visible = NO;
        self.cannonBallRight.visible = NO;
  8. The hit method has the following content...