SpriteKitのjointを使って、ぼよんぼよんボールを跳ねさせるiPhoneアプリを描いてみます。
動作イメージ
XcodeからiOS7 iPhone Simulatorで動かすとこんな感じになります。
サンプルコード
#import “ViewController.h”
#import <SpriteKit/SpriteKit.h>
@interface BigBall : SKScene
@property BOOL contentCreated;
@end
@implementation BigBall
– (void)didMoveToView:(SKView *)view
{
if (!self.contentCreated) {
[self createSceneContents];
self.contentCreated = YES;
}
}
– (void)createSceneContents
{
SKSpriteNode *ground = [[SKSpriteNode alloc] initWithColor:[SKColor redColor] size:CGSizeMake(320, 10)];
ground.position = CGPointMake(160, 10);
[self addChild:ground];
ground.physicsBody = [SKPhysicsBody bodyWithRectangleOfSize:ground.size];
ground.physicsBody.dynamic = NO;
SKShapeNode *center =[SKShapeNode node];
center.path = [UIBezierPath bezierPathWithOvalInRect:CGRectMake(-10, –10, 20, 20)].CGPath;
center.position = CGPointMake(160, 300);
[self addChild:center];
center.physicsBody = [SKPhysicsBody bodyWithCircleOfRadius:10];
center.name = @”center”;
float dAngle = M_PI / 10.0;
SKNode *first;
SKNode *previous;
for (int i=0; i<20; i++) {
float x = 100 * cos(dAngle * i) + 160;
float y = 100 * sin(dAngle * i) + 300;
SKShapeNode *n = [SKShapeNode node];
n.path = [UIBezierPath bezierPathWithOvalInRect:CGRectMake(-10, –10, 20, 20)].CGPath;
n.position = CGPointMake(x, y);
[self addChild:n];
n.physicsBody = [SKPhysicsBody bodyWithCircleOfRadius:10];
SKPhysicsJointSpring *joint = [SKPhysicsJointSpring jointWithBodyA:center.physicsBody bodyB:n.physicsBody anchorA:CGPointMake(160, 300) anchorB:CGPointMake(x, y)];
joint.damping = 0.2;
joint.frequency = 10.0;
[self.physicsWorld addJoint:joint];
if (previous) {
SKPhysicsJointLimit *limit = [SKPhysicsJointLimit jointWithBodyA:previous.physicsBody bodyB:n.physicsBody anchorA:previous.position anchorB:n.position];
limit.maxLength = 30;
[self.physicsWorld addJoint:limit];
} else {
first = n;
}
previous = n;
}
SKPhysicsJointLimit *limit = [SKPhysicsJointLimit jointWithBodyA:previous.physicsBody bodyB:first.physicsBody anchorA:previous.position anchorB:first.position];
limit.maxLength = 30;
[self.physicsWorld addJoint:limit];
}
– (void)touchesBegan:(NSSet *)touches withEvent:(UIEvent *)event
{
SKNode *node = [self childNodeWithName:@”center”];
[node.physicsBody applyImpulse:CGVectorMake(0, 100)];
}
@end
@interface ViewController ()
@end
@implementation ViewController
– (void)viewDidLoad
{
[super viewDidLoad];
SKView *spriteView = [[SKView alloc] initWithFrame:self.view.bounds];
[self.view addSubview:spriteView];
SKScene *scene = [[BigBall alloc] initWithSize:self.view.bounds.size];
[spriteView presentScene:scene];
}
– (void)didReceiveMemoryWarning
{
[super didReceiveMemoryWarning];
// Dispose of any resources that can be recreated.
}
@end