子类化SKSpriteNode时物理主体的问题？

Question

我在子类化SKSpriteNode时遇到了问题。 这是我的子类实现：

@implementation SSSquirrel
- (id) init {
    if (self = [super init]) {

        // Create Squirrel and physics body
        SKSpriteNode *squirrel = [SKSpriteNode spriteNodeWithImageNamed:@"squirrelNormal"];
        squirrel.physicsBody = [SKPhysicsBody bodyWithCircleOfRadius:squirrel.size.width/2 - 10];
        squirrel.physicsBody.dynamic = NO;
        squirrel.physicsBody.affectedByGravity = NO;
        squirrel.physicsBody.restitution = 0.8;
        squirrel.physicsBody.friction = 0.1;
        squirrel.zPosition = 1.0;

        [self addChild:squirrel];

    }
    return self;
}

@end

然后我在我的主要游戏场景中创建了一只松鼠：

    SSSquirrel *squirrel1 = [[SSSquirrel alloc] init];
    squirrel1.position = CGPointMake(offset, self.frame.size.height - offset);
    [self addChild:squirrel1];

一切都创造得很好。 然而，在游戏过程中，我尝试在触摸开始时“暂停”松鼠物理体，然后在触摸结束时重新启用它（tempSquirrelBody是场景的SKPhysicsBody实例变量）。 基本上我试图给出一种错觉，即当用户触摸屏幕时，松鼠正朝着用户和其他物体移动。

-(void)touchesBegan:(NSSet *)touches withEvent:(UIEvent *)event {
/* Called when a touch begins */

for (UITouch *touch in touches) {

    tempSquirrelBody = squirrel1.physicsBody;
    squirrel1.physicsBody = nil;

    CGPoint newPosition = squirrel1.position;
    newPosition.x -= 60;
    newPosition.y += 60;

    squirrel1.position = newPosition;
    squirrel1.texture = [SKTexture textureWithImageNamed:@"squirrelUp"];

}
}

- (void)touchesEnded:(NSSet *)touches withEvent:(UIEvent *)event {
/* Called when a touch ends */

for (UITouch *touch in touches) {

    CGPoint newPosition = squirrel1.position;
    newPosition.x += 60;
    newPosition.y -= 60;
    squirrel1.position = newPosition;
    squirrel1.texture = [SKTexture textureWithImageNamed:@"squirrelNormal"];

    squirrel1.physicsBody = tempSquirrelBody;

}

}

不幸的是，这不起作用; 当物理体被设置为零时，物理体不会被悬浮，松鼠会与其他物体发生碰撞。 当我将代码从我的SSSquirrel类移动到游戏场景时，它可以工作。 我做错了什么？

谢谢！

Answer 1

将collisionBitMask设置为0而不是将整个physicsBody设置为nil会不会更容易？

-(void)touchesBegan:(NSSet *)touches withEvent:(UIEvent *)event {
/* Called when a touch begins */

for (UITouch *touch in touches) {

    squirrel1.physicsBody.collisionBitMask = 0;

    CGPoint newPosition = squirrel1.position;
    newPosition.x -= 60;
    newPosition.y += 60;

    squirrel1.position = newPosition;
    squirrel1.texture = [SKTexture textureWithImageNamed:@"squirrelUp"];

}
}

- (void)touchesEnded:(NSSet *)touches withEvent:(UIEvent *)event {
/* Called when a touch ends */

for (UITouch *touch in touches) {

    CGPoint newPosition = squirrel1.position;
    newPosition.x += 60;
    newPosition.y -= 60;
    squirrel1.position = newPosition;
    squirrel1.texture = [SKTexture textureWithImageNamed:@"squirrelNormal"];

    squirrel1.physicsBody.collisionBitMask = 0xFFFFFFFF;

}

}