画面の端にぶつかると、進む向きが反転する車をジャンプさせる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 TurnScene : SKScene
@property (nonatomic) int direction;
@end
@implementation TurnScene
– (void)didMoveToView:(SKView *)view
{
self.physicsBody = [SKPhysicsBody bodyWithEdgeLoopFromRect:self.frame];
self.backgroundColor = [SKColor lightGrayColor];
[self createLine];
[self createCar];
}
– (void)createLine
{
float pt[] = {70, 50, 250, 100, 100, 180, 240, 250, 80, 320};
for (int i=0; i<0.5 * sizeof(pt)/sizeof(float); i++) {
SKSpriteNode *node = [SKSpriteNode spriteNodeWithColor:[SKColor grayColor] size:CGSizeMake(120, 5)];
node.position = CGPointMake(pt[2*i], pt[2*i+1]);
[self addChild:node];
node.physicsBody = [SKPhysicsBody bodyWithRectangleOfSize:node.size];
node.physicsBody.dynamic = NO;
}
}
– (void)createCar
{
SKSpriteNode *car = [SKSpriteNode spriteNodeWithColor:[SKColor redColor] size:CGSizeMake(50, 20)];
car.name = @”car”;
car.position = CGPointMake(40, 30);
[self addChild:car];
car.physicsBody = [SKPhysicsBody bodyWithRectangleOfSize:car.size];
car.physicsBody.allowsRotation = NO;
UIBezierPath *path = [UIBezierPath bezierPathWithArcCenter:CGPointZero radius:8 startAngle:0 endAngle:2.0*M_PI clockwise:NO];
for (int i=0; i<2; i++) {
SKShapeNode *tire = [SKShapeNode node];
tire.name = @”tire”;
tire.path = path.CGPath;
tire.position = CGPointMake(i==0 ? 20 : 60, 20);
tire.strokeColor = [SKColor blackColor];
tire.lineWidth = 5;
tire.fillColor = [SKColor whiteColor];
[self addChild:tire];
tire.physicsBody = [SKPhysicsBody bodyWithCircleOfRadius:8];
SKPhysicsJointPin *pin = [SKPhysicsJointPin jointWithBodyA:tire.physicsBody bodyB:car.physicsBody anchor:tire.position];
[self.physicsWorld addJoint:pin];
}
}
– (void)update:(NSTimeInterval)currentTime
{
[self enumerateChildNodesWithName:@”tire” usingBlock:^(SKNode *node, BOOL *stop) {
if (self.direction == 0) {
node.physicsBody.angularVelocity = –15;
} else {
node.physicsBody.angularVelocity = 15;
}
}];
SKNode *car = [self childNodeWithName:@”car”];
if (self.direction == 0 && car.position.x > 270) {
self.direction = 1;
} else if (self.direction == 1 && car.position.x < 50) {
self.direction = 0;
}
}
– (void)touchesBegan:(NSSet *)touches withEvent:(UIEvent *)event
{
SKNode *car = [self childNodeWithName:@”car”];
[car.physicsBody applyImpulse:CGVectorMake(0, 35)];
}
@end
@interface ViewController ()
@end
@implementation ViewController
– (void)viewDidLoad
{
[super viewDidLoad];
SKView *spriteView = [[SKView alloc] initWithFrame:self.view.bounds];
[self.view addSubview:spriteView];
SKScene *scene = [[TurnScene alloc] initWithSize:spriteView.frame.size];
[spriteView presentScene:scene];
}
@end