子類化SKSpriteNode時物理主體的問題？

Question

我在子類化SKSpriteNode時遇到了問題。 這是我的子類實現：

@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戲場景中創建了一只松鼠：

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

一切都創造得很好。 然而，在游戲過程中，我嘗試在觸摸開始時“暫停”松鼠物理體，然后在觸摸結束時重新啟用它（tempSquirrelBody是場景的SKPhysicsBody實例變量）。 基本上我試圖給出一種錯覺，即當用戶觸摸屏幕時，松鼠正朝着用戶和其他物體移動。

-(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，這不起作用; 當物理體被設置為零時，物理體不會被懸浮，松鼠會與其他物體發生碰撞。 當我將代碼從我的SSSquirrel類移動到游戲場景時，它可以工作。 我做錯了什么？

謝謝！

Answer 1

將collisionBitMask設置為0而不是將整個physicsBody設置為nil會不會更容易？

-(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;

}

}