.m file

//
//  ORBMyScene.m
//  (removed)
//
//  Created by (removed) on 2014-04-27.
//  Copyright (c) 2014 (removed). All rights reserved.
//

#import "ORBGameScene.h"
#import "ORBMenuScene.h"
#import "CGVector+TC.h"

enum {
    CollisionPlayer = 1<<1,
    CollisionEnemy = 1<<2,
};



@interface ORBGameScene () <SKPhysicsContactDelegate>
@end

@implementation ORBGameScene
{
    SKNode *_player;
    NSMutableArray *_enemies;
    BOOL _dead;
    SKLabelNode *_scorelabel;
}

-(id)initWithSize:(CGSize)size {
    if (self = [super initWithSize:size]) {

        SKSpriteNode *background = [SKSpriteNode spriteNodeWithImageNamed:@"backbground"];
        background.position = CGPointMake(CGRectGetMidX(self.frame),CGRectGetMidY(self.frame));

        self.physicsWorld.gravity = CGVectorMake(0, 0);
        self.physicsWorld.contactDelegate = self;

        _enemies = [NSMutableArray new];

        _player = [SKNode node];
            SKShapeNode *circle = [SKShapeNode node];
            circle.path = [UIBezierPath bezierPathWithOvalInRect:CGRectMake(0, 0, 20, 20)].CGPath;
            circle.fillColor = [UIColor blueColor];
            circle.strokeColor = [UIColor blueColor];
            circle.glowWidth = 5;

            SKEmitterNode *trail = [SKEmitterNode orb_emitterNamed:@"Trail"];
            trail.targetNode = self;
            trail.position = CGPointMake(CGRectGetMidX(circle.frame), CGRectGetMidY(circle.frame));
            [_player addChild:trail];

            _player.physicsBody = [SKPhysicsBody bodyWithCircleOfRadius:10];
            _player.physicsBody.mass = 100000;
            _player.physicsBody.categoryBitMask = CollisionPlayer;
            _player.physicsBody.contactTestBitMask = CollisionEnemy;

            _player.position = CGPointMake(size.width/2, size.height/2);

              [self addChild:background];
        [self addChild:_player];
    }
    return self;
}

- (void)didMoveToView:(SKView *)view
{
        [self runAction:[SKAction group:@[
/*            [SKAction spawnPlayer] => spawn animation, then add player to world,*/
        ]]];
    [self performSelector:@selector(spawnEnemy) withObject:nil afterDelay:1.0];
}

- (void)spawnEnemy
{
    SKNode *enemy = [SKNode node];

        SKEmitterNode *trail = [SKEmitterNode orb_emitterNamed:@"Trail"];
        trail.targetNode = self;
        trail.particleColorSequence = [[SKKeyframeSequence alloc] initWithKeyframeValues:@[
            [SKColor redColor],
            [SKColor colorWithHue:0.1 saturation:.5 brightness:1 alpha:1],
            [SKColor redColor],
        ] times:@[@0, @0.02, @0.2]];
        trail.particleScale /= 2;
        trail.position = CGPointMake(10, 10);
        [enemy addChild:trail];

        CGFloat radius = MAX(self.size.height, self.size.width)/2;
        CGFloat angle = (arc4random_uniform(1000)/1000.) * M_PI*2;
        CGPoint p = CGPointMake(cos(angle)*radius, sin(angle)*radius);
        enemy.position = CGPointMake(self.size.width/2 + p.x, self.size.width/2 + p.y);

        enemy.physicsBody = [SKPhysicsBody bodyWithCircleOfRadius:6];
        enemy.physicsBody.categoryBitMask = CollisionEnemy;
        enemy.physicsBody.allowsRotation = NO;

    [_enemies addObject:enemy];
    [self addChild:enemy];

    if(!_scorelabel) {
        _scorelabel = [SKLabelNode labelNodeWithFontNamed:@"Courier-Bold"];

        _scorelabel.fontSize = 200;
        _scorelabel.position = CGPointMake(CGRectGetMidX(self.frame), CGRectGetMidY(self.frame));
        _scorelabel.fontColor = [SKColor colorWithHue: 0 saturation: 0 brightness: 1 alpha: .5];
        [self addChild:_scorelabel];

    }
    _scorelabel.text = [NSString stringWithFormat:@"%02d", _enemies.count];

    // Next spawn
    [self runAction:[SKAction sequence:@[
        [SKAction waitForDuration:5],
        [SKAction performSelector:@selector(spawnEnemy) onTarget:self],
    ]]];
}

- (void)dieFrom:(SKNode*)killingEnemy
{
    _dead = YES;

    SKEmitterNode *explosion = [SKEmitterNode orb_emitterNamed:@"Explosion"];
    explosion.position = _player.position;
    [self addChild:explosion];
    [explosion runAction:[SKAction sequence:@[
        [SKAction playSoundFileNamed:@"Explosion.wav" waitForCompletion:NO],
        [SKAction waitForDuration:0.4],
        [SKAction runBlock:^{
            // TODO: Remove these more nicely
            [killingEnemy removeFromParent];
            [_player removeFromParent];
        }],
        [SKAction waitForDuration:0.4],
        [SKAction runBlock:^{
            explosion.particleBirthRate = 0;
        }],
        [SKAction waitForDuration:1.2],

        [SKAction runBlock:^{
            ORBMenuScene *menu = [[ORBMenuScene alloc] initWithSize:self.size];
            [self.view presentScene:menu transition:[SKTransition doorsCloseHorizontalWithDuration:0.5]];
        }],
    ]]];
}

- (void)touchesBegan:(NSSet *)touches withEvent:(UIEvent *)event
{
    [self touchesMoved:touches withEvent:event];
}

- (void)touchesMoved:(NSSet *)touches withEvent:(UIEvent *)event
{
    if(_dead)
        return;

    [_player runAction:[SKAction moveTo:[[touches anyObject] locationInNode:self] duration:0.01]];
}

-(void)update:(CFTimeInterval)currentTime
{

    CGPoint playerPos = _player.position;

    for(SKNode *enemyNode in _enemies) {
        CGPoint enemyPos = enemyNode.position;

        /* Uniform speed: */
        CGVector diff = TCVectorMinus(playerPos, enemyPos);
        CGVector normalized = TCVectorUnit(diff);
        CGVector force = TCVectorMultiply(normalized, 4);

        /* Inversely proportional:
        CGVector diff = TCVectorMinus(playerPos, enemyPos);
        CGVector normalized = TCVectorUnit(diff);
        CGVector force = TCVectorMultiply(normalized, 1/sqrt(TCVectorLength(diff))*40);
        */

        /* Inverse square root
        CGVector diff = TCVectorMinus(playerPos, enemyPos);
        CGVector normalized = TCVectorUnit(diff);
        CGVector force = TCVectorMultiply(normalized, 1/sqrt(TCVectorLength(diff))*40);
        */

        [enemyNode.physicsBody applyForce:force];
    }

    _player.physicsBody.velocity = CGVectorMake(0, 0);
}

- (void)didBeginContact:(SKPhysicsContact *)contact
{
    if(_dead)
        return;

    [self dieFrom:contact.bodyB.node];
    contact.bodyB.node.physicsBody = nil;
}

@end

@implementation SKEmitterNode (fromFile)
+ (instancetype)orb_emitterNamed:(NSString*)name
{
    return [NSKeyedUnarchiver unarchiveObjectWithFile:[[NSBundle mainBundle] pathForResource:name ofType:@"sks"]];
}
@end