我被这个碰撞问题吓坏了：快速平移时，平移的球会从边缘循环体中脱落。有人有类似的问题吗？这是说明问题的场景代码。（替换 xcode 示例中的 MyScene - spritekitgame）
#import "SAMyScene.h"
/* Bitmask for the different entities with physics bodies. */
typedef enum : uint32_t {
SAColliderTypeBall = 0x1 << 1
,SAColliderTypeEdge = 0x1 << 3
} SAColliderType;
NSString * const SABallName = @"ballNode";
@interface SAMyScene()
@property (nonatomic, strong) UIPanGestureRecognizer *panGestureRecognizer;
@property (nonatomic, strong) SKShapeNode *ball;
@end
@implementation SAMyScene
-(id)initWithSize:(CGSize)size {
if (self = [super initWithSize:size]) {
/* Setup your scene here */
NSLog(@"Ball categorie bitmask =%d", SAColliderTypeBall);
NSLog(@"Edges categorie bitmask =%d", SAColliderTypeEdge);
self.backgroundColor = [SKColor colorWithRed:0.15 green:0.15 blue:0.3 alpha:1.0];
self.physicsBody = [SKPhysicsBody bodyWithEdgeLoopFromRect:self.frame];
self.physicsBody.categoryBitMask = SAColliderTypeEdge;
self.physicsBody.usesPreciseCollisionDetection = YES;
self.ball = [self newBallNode];
[self addChild:self.ball];
}
return self;
}
- (SKShapeNode *)newBallNode {
SKShapeNode *ball = [[SKShapeNode alloc] init];
CGMutablePathRef myPath = CGPathCreateMutable();
CGFloat radius = 60.0;
CGPathAddArc(myPath, NULL, 0,0, radius, 0, M_PI*2, YES);
ball.path = myPath;
ball.fillColor = [SKColor yellowColor];
ball.name = SABallName;
ball.position = CGPointMake(CGRectGetMidX(self.frame),CGRectGetMidY(self.frame));
ball.physicsBody = [SKPhysicsBody bodyWithCircleOfRadius:radius];
ball.physicsBody.affectedByGravity = NO;
ball.physicsBody.dynamic = YES;
ball.physicsBody.categoryBitMask = SAColliderTypeBall;
ball.physicsBody.contactTestBitMask = SAColliderTypeEdge;
ball.physicsBody.collisionBitMask = SAColliderTypeEdge;
ball.physicsBody.usesPreciseCollisionDetection = YES;
return ball;
}
-(void)update:(CFTimeInterval)currentTime {
//Called before each frame is rendered
}
- (UIPanGestureRecognizer *)panGestureRecognizer {
if (!_panGestureRecognizer) {
_panGestureRecognizer = [[UIPanGestureRecognizer alloc] initWithTarget:self
action:@selector(handlePanFrom:)];
}
return _panGestureRecognizer;
}
- (void)didMoveToView:(SKView *)view {
if (![[self view].gestureRecognizers containsObject:self.panGestureRecognizer]) {
[[self view] addGestureRecognizer:self.panGestureRecognizer];
}
}
- (void)handlePanFrom:(UIPanGestureRecognizer *)recognizer {
if (recognizer.state == UIGestureRecognizerStateBegan) {
} else if (recognizer.state == UIGestureRecognizerStateChanged) {
CGPoint translation = [recognizer translationInView:recognizer.view];
translation = CGPointMake(translation.x, - translation.y);
[self panForTranslation:translation];
[recognizer setTranslation:CGPointZero inView:recognizer.view];
} else if (recognizer.state == UIGestureRecognizerStateEnded) {
}
}
- (void)panForTranslation:(CGPoint)translation {
CGPoint position = self.ball.position;
CGPoint newPos = CGPointMake(position.x + translation.x, position.y);
self.ball.position = newPos;
}
@end