Write the Code

1. Write the Code Change the World

2. They Already Have Changed the World • Facebook • Twitter • Pandora • Candy Crush • Instagram • Snapchat

3. How to Do It • Terminology • Platforms • Tools • Let’s Make an App

4. Terminology • Code • App • Development Environment • Build, Run, Crash, Debug • Compile • Simulator • xCode

5. Platforms • Microsoft – Windows (Computers and Phones) • Internet Browsers – Safari, Chrome, Firefox, Internet Explorer • Apple – OSX (Computers) • Apple – iOS (iPhone, iPad, Apple Watch) • Google – Android

6. Tools • xCode • Simulator • Google • Stack Exchange • Tutorials

7. Let’s Make an App • Go to App Store, Download and Install xCode • Launch xCode • File, New, Project, Application, Game • Run • Hello World • Now, Change the World • Run Again

8. Getting Around in xCode

9. Lesson #2 Building an iPhone Game

10. Get the Resources • http://www.raywenderlich.com/42699/spritekit-tutorial-for-beginners • http://cdn3.raywenderlich.com/wp-content/uploads/2015/01/SpriteKitSimpleGameResources.zip

11. Start CodingGameScene.m #import “GameScene.h” // 1 @interface GameScene() @property (nonatomic) SKSpriteNode * player; @end @implementation GameScene -(id)initWithSize:(CGSize)size { if (self = [super initWithSize:size]) { //2 NSLog(@”Size: %@”, NSStringFromCGSize(size)); // 3 self.backgroundColor = [SKColor colorWithRed:1.0 green: 1.0 blue: 1.0 alpha:1.0]; // 4 self.player = [SKSpriteNodespriteNodeWithImageNamed:@”player”]; self.player.position = CGPointMake(100,100); [self addChold:self.player]; } return self; }

12. Add Player to Screen • Open ViewController.m • Replace ViewDidLoad with viewWillLayoutSubviews

13. GameViewContoller.mviewWillLayoutSubviews -(void)viewWillLayoutSubviews { [super viewWillLayoutSubviews]; // Configure the View SKView * skView = (SKView *)self.view; if (!skView.scene) { skView.showFPS = YES; skView.showNodeCount = YES; // Create and configure the Screen SKScene * scene = [ GameScenesceneWithSize:skView.bounds.size]; scene.scaleMode = SKSceneScaleModeAspectFill; // Present the Scene [skViewpresentScene:scene]; } }

14. Move the Player • Open GameScene.m self.player.position = CGPointMake(self.player.size.width/2, self.frame.size.height/2);

15. Add the Bad Guys • Implement AddMonster • Make the Monsters Move

16. AddMonsterGameScene.m - (void)addMonster { // Create sprite SKSpriteNode * monster = [SKSpriteNodespriteNodeWithImageNamed:@"monster"]; // Determine where to spawn the monster along the Y axis intminY = monster.size.height / 2; intmaxY = self.frame.size.height - monster.size.height / 2; intrangeY = maxY - minY; intactualY = (arc4random() % rangeY) + minY; // Create the monster slightly off-screen along the right edge, // and along a random position along the Y axis as calculated above monster.position = CGPointMake(self.frame.size.width + monster.size.width/2, actualY); [self addChild:monster]; // Determine speed of the monster intminDuration = 2.0; intmaxDuration = 4.0; intrangeDuration = maxDuration - minDuration; intactualDuration = (arc4random() % rangeDuration) + minDuration; // Create the actions SKAction * actionMove = [SKActionmoveTo:CGPointMake(-monster.size.width/2, actualY) duration:actualDuration]; SKAction * actionMoveDone = [SKActionremoveFromParent]; [monster runAction:[SKAction sequence:@[actionMove, actionMoveDone]]]; }

17. Shoot ‘em UpGameScene.m static inline CGPointrwAdd(CGPoint a, CGPoint b) { return CGPointMake(a.x + b.x, a.y + b.y); } static inline CGPointrwSub(CGPoint a, CGPoint b) { return CGPointMake(a.x - b.x, a.y - b.y); } static inline CGPointrwMult(CGPoint a, float b) { return CGPointMake(a.x * b, a.y * b); } static inline float rwLength(CGPoint a) { returnsqrtf(a.x * a.x + a.y * a.y); } // Makes a vector have a lengthof 1 staticinlineCGPointrwNormalize(CGPoint a) { floatlength = rwLength(a); returnCGPointMake(a.x / length, a.y / length); }

18. Shoot ‘em UpHandling Touches -(void)touchesEnded:(NSSet *)touches withEvent:(UIEvent *)event { // 1 - Choose one of the touches to work with UITouch * touch = [touches anyObject]; CGPoint location = [touch locationInNode:self]; // 2 - Set up initial location of projectile SKSpriteNode * projectile = [SKSpriteNodespriteNodeWithImageNamed:@"projectile"]; projectile.position = self.player.position; // 3- Determine offset of location to projectile CGPoint offset = rwSub(location, projectile.position); // 4 - Bail out if you are shooting down or backwards if (offset.x <= 0) return; // 5 - OK to add now - we've double checked position [self addChild:projectile]; // 6 - Get the direction of where to shoot CGPoint direction = rwNormalize(offset); // 7 - Make it shoot far enough to be guaranteed off screen CGPointshootAmount = rwMult(direction, 1000); // 8 - Add the shoot amount to the current position CGPointrealDest = rwAdd(shootAmount, projectile.position); // 9 - Create the actions float velocity = 480.0/1.0; float realMoveDuration = self.size.width / velocity; SKAction * actionMove = [SKActionmoveTo:realDestduration:realMoveDuration]; SKAction * actionMoveDone = [SKActionremoveFromParent]; [projectile runAction:[SKAction sequence:@[actionMove, actionMoveDone]]]; }

19. Shoot ‘em UpCollision Detection GameScene.m static const uint32_t projectileCategory = 0x1 << 0; static const uint32_t monsterCategory = 0x1 << 1; GameScene.m / initWithSize self.physicsWorld.gravity = CGVectorMake(0,0); self.physicsWorld.contactDelegate = self; GameScene.m / addMonster / afterCreating Monster monster.physicsBody = [SKPhysicsBodybodyWithRectangleOfSize:monster.size]; // 1 monster.physicsBody.dynamic = YES; // 2 monster.physicsBody.categoryBitMask = monsterCategory; // 3 monster.physicsBody.contactTestBitMask = projectileCategory; // 4 monster.physicsBody.collisionBitMask = 0; // 5 GameScene.m / TouchesEnded / after setting projectile position projectile.physicsBody = [SKPhysicsBodybodyWithCircleOfRadius:projectile.size.width/2]; projectile.physicsBody.dynamic = YES; projectile.physicsBody.categoryBitMask = projectileCategory; projectile.physicsBody.contactTestBitMask = monsterCategory; projectile.physicsBody.collisionBitMask = 0; projectile.physicsBody.usesPreciseCollisionDetection = YES;

20. Shoot ‘em UpCollision Detection GameScene.m - (void)projectile:(SKSpriteNode *)projectile didCollideWithMonster:(SKSpriteNode *)monster { NSLog(@"Hit"); [projectile removeFromParent]; [monster removeFromParent]; } - (void)didBeginContact:(SKPhysicsContact *)contact { // 1 SKPhysicsBody *firstBody, *secondBody; if (contact.bodyA.categoryBitMask < contact.bodyB.categoryBitMask) { firstBody = contact.bodyA; secondBody = contact.bodyB; } else { firstBody = contact.bodyB; secondBody = contact.bodyA; } // 2 if ((firstBody.categoryBitMask & projectileCategory) != 0 && (secondBody.categoryBitMask & monsterCategory) != 0) { [self projectile:(SKSpriteNode *) firstBody.nodedidCollideWithMonster:(SKSpriteNode *) secondBody.node]; } }

21. Shoot ‘em UpCollision Detection GameScene.h / Implement Delegate @interface GameScene() <SKPhysicsContactDelegate>

22. Sound Check GameViewController.m @import AVFoundation; @interface GameViewController() @property (nonatomic) AVAudioPlayer * backgroundMusicPlayer; @end GameViewController.m / viewWillLayoutSubviews / after [super viewWillLayoutSubviews] NSError *error; NSURL * backgroundMusicURL = [[NSBundle mainBundle] URLForResource:@"background-music-aac" withExtension:@"caf"]; self.backgroundMusicPlayer = [[AVAudioPlayeralloc] initWithContentsOfURL:backgroundMusicURL error:&error]; self.backgroundMusicPlayer.numberOfLoops = -1; [self.backgroundMusicPlayerprepareToPlay]; [self.backgroundMusicPlayer play]; GameScene.m / TouchesEnded / at the top [self runAction:[SKActionplaySoundFileNamed:@"pew-pew-lei.caf" waitForCompletion:NO]];

23. Winners and Losers • Now, let’s create a new scene and layer that will serve as your “You Win” or “You Lose” indicator. • Create a new file with the iOS\Cocoa Touch\Objective-C class template, name the class GameOverScene, make it a subclass of SKScene, and click Next and then Create. • GameOverScene.h • #import <SpriteKit/SpriteKit.h> • @interface GameOverScene : SKScene • -(id)initWithSize:(CGSize)size won:(BOOL)won; • @end

24. Winners and LosersGameOverScene.m #import "GameOverScene.h" #import “GameScene.h" @implementation GameOverScene -(id)initWithSize:(CGSize)size won:(BOOL)won { if (self = [super initWithSize:size]) { // 1 self.backgroundColor = [SKColor colorWithRed:1.0 green:1.0 blue:1.0 alpha:1.0]; // 2 NSString * message; if (won) { message = @"You Won!"; } else { message = @"You Lose :["; } // 3 SKLabelNode *label = [SKLabelNodelabelNodeWithFontNamed:@"Chalkduster"]; label.text = message; label.fontSize = 40; label.fontColor = [SKColorblackColor]; label.position = CGPointMake(self.size.width/2, self.size.height/2); [self addChild:label]; // 4 [self runAction: [SKAction sequence:@[ [SKAction waitForDuration:3.0], [SKActionrunBlock:^{ // 5 SKTransition *reveal = [SKTransition flipHorizontalWithDuration:0.5]; SKScene * myScene = [[GameScenealloc] initWithSize:self.size]; [self.viewpresentScene:myScene transition: reveal]; }] ]] ]; } return self; } @end

25. Winners and LosersFinishing Up GameScene.m #import "GameOverScene.h" GameScene.m / addMonster / replace Last Line SKAction * loseAction = [SKActionrunBlock:^{ SKTransition *reveal = [SKTransition flipHorizontalWithDuration:0.5]; SKScene * gameOverScene = [[GameOverScenealloc] initWithSize:self.sizewon:NO]; [self.viewpresentScene:gameOverScene transition: reveal]; }]; [monster runAction:[SKAction sequence:@[actionMove, loseAction, actionMoveDone]]]; GameScene.m / addToInterface @property (nonatomic) intmonstersDestroyed; gameScene.m / projectile:didCollideWithMonster / bottom self.monstersDestroyed++; if (self.monstersDestroyed > 30) { SKTransition *reveal = [SKTransition flipHorizontalWithDuration:0.5]; SKScene * gameOverScene = [[GameOverScenealloc] initWithSize:self.sizewon:YES]; [self.viewpresentScene:gameOverScene transition: reveal]; }