画面上を走っていくクルマの数をカウントするiPhoneアプリのサンプルコードを描いてみます。
#import “ViewController.h”
#import <SpriteKit/SpriteKit.h>
@interface TrafficScene : SKScene
@property int state;
@end
@implementation TrafficScene
– (void)didMoveToView:(SKView *)view
{
[self createRoad];
}
– (void)createRoad
{
SKLabelNode *title = [SKLabelNode node];
title.text = @”Traffic”;
title.position = CGPointMake(CGRectGetMidX(self.frame), CGRectGetMaxY(self.frame) – 50);
[self addChild:title];
for (int i=0; i<4; i++) {
SKSpriteNode *road = [SKSpriteNode spriteNodeWithColor:[SKColor colorWithHue:0.25 * i saturation:0.3 brightness:1.0 alpha:1.0] size:CGSizeMake(CGRectGetMaxX(self.frame), CGRectGetMaxY(self.frame)/5.0)];
road.position = CGPointMake(CGRectGetMidX(self.frame), CGRectGetMaxY(self.frame)/5.0 * i + 30);
[self addChild:road];
SKLabelNode *counter = [SKLabelNode node];
counter.name = [NSString stringWithFormat:@”counter%d”, i];
counter.text = @”0″;
counter.position = CGPointMake(CGRectGetMaxX(self.frame) – 80, road.position.y);
[self addChild:counter];
}
}
– (SKNode *)createCar
{
SKNode *car = [SKNode node];
[self addChild:car];
SKSpriteNode *body = [SKSpriteNode spriteNodeWithColor:[SKColor orangeColor] size:CGSizeMake(30, 12)];
[car addChild:body];
SKSpriteNode *roof = [SKSpriteNode spriteNodeWithColor:[SKColor orangeColor] size:CGSizeMake(15, 10)];
roof.position = CGPointMake(0, 10);
[car addChild:roof];
UIBezierPath *path = [UIBezierPath bezierPathWithArcCenter:CGPointZero radius:3 startAngle:0 endAngle:2.0*M_PI clockwise:NO];
for (int i=0; i<2; i++) {
SKShapeNode *tire = [SKShapeNode node];
tire.position = CGPointMake(20 * i – 10, –5);
tire.path = path.CGPath;
tire.fillColor = [SKColor lightGrayColor];
tire.strokeColor = [SKColor blackColor];
tire.lineWidth = 2;
[car addChild:tire];
}
return car;
}
– (void)update:(NSTimeInterval)currentTime
{
if (self.state != 1) {
return;
}
int rand = arc4random() % 100;
if (rand < 4) {
SKNode *car = [self createCar];
car.position = CGPointMake(-50, CGRectGetMaxY(self.frame)/5.0 * rand + 30);
[car runAction:[SKAction moveToX:CGRectGetMaxX(self.frame)+30 duration:arc4random()%2+3] completion:^{
[car removeFromParent];
SKLabelNode *counter = (SKLabelNode *)[self childNodeWithName:[NSString stringWithFormat:@”counter%d”, rand]];
counter.text = [NSString stringWithFormat:@”%d”, [counter.text intValue]+1];
}];
}
}
– (void)touchesBegan:(NSSet *)touches withEvent:(UIEvent *)event
{
self.state = 1;
}
@end
@interface ViewController ()
@end
@implementation ViewController
– (void)viewDidAppear:(BOOL)animated
{
SKView *spriteView = [[SKView alloc] initWithFrame:self.view.bounds];
[self.view addSubview:spriteView];
SKScene *scene = [[TrafficScene alloc] initWithSize:spriteView.frame.size];
[spriteView presentScene:scene];
}
@end