ios - didBeginContact 方法不起作用

Question

我的 didBeginContact 方法应该在球击中时移除我的砖 block Sprite 。但是，它没有发挥作用。当我运行它时，当我击中桨和击中砖 block 时，我会得到 NSLog“桨”。我已经多次查看了代码，有人可以告诉我这里加入了什么吗？

@interface GameScene ()

@property (nonatomic) SKSpriteNode *paddle;

@end


static const uint32_t ballCategory   = 1;       //00000000000000000000000000000001
static const uint32_t brickCategory  = 2;       //00000000000000000000000000000010
static const uint32_t paddleCategory = 4;       //00000000000000000000000000000100
static const uint32_t edgeCategory   = 8;       //00000000000000000000000000001000
static const uint32_t bottomEdgeCategory = 16;  //00000000000000000000000000010000


@implementation GameScene

-(void)didBeginContact:(SKPhysicsContact *)contact {

    //create placeholder for the "non ball" object
    SKPhysicsBody *notTheBall;



    if (contact.bodyA.categoryBitMask < contact.bodyB.categoryBitMask) {
        notTheBall = contact.bodyB;
    } else {
        notTheBall = contact.bodyB;
    }
    if (notTheBall.categoryBitMask == brickCategory) {
        NSLog(@"brick");
        [notTheBall.node removeFromParent];
    } else {
        NSLog(@"paddle");
    }


}

- (void) addBall:(CGSize)size {
    //create sprite with image
    SKSpriteNode *ball = [SKSpriteNode spriteNodeWithImageNamed:@"ball"];
    //resize sprite
    ball.size = CGSizeMake(33, 33);
    //position it
    ball.position = CGPointMake(size.width/2, size.height/2);
    //give physics to ball
    ball.physicsBody = [SKPhysicsBody bodyWithCircleOfRadius:ball.frame.size.width/2];
    ball.physicsBody.friction = 0;
    ball.physicsBody.linearDamping = 0;
    ball.physicsBody.restitution = 1.0f;
    ball.physicsBody.categoryBitMask = ballCategory;
    ball.physicsBody.contactTestBitMask = brickCategory | paddleCategory;


    //add sprite to scene
    [self addChild:ball];

    //create vector
    CGVector myVector = CGVectorMake(20, 20);
    //apply vector to ballphysics body
    [ball.physicsBody applyImpulse:myVector];

}

- (void) addBricks:(CGSize)size {
    for (int i = 0; i < 5; i++) {
        //create brick sprite from image
        SKSpriteNode *brick = [SKSpriteNode spriteNodeWithImageNamed:@"brick"];
        //resize bricks
        brick.size = CGSizeMake(60, 30);
        //psoition bricks
        int xPos = size.width/5 * (i+.5);
        int yPos = size.height - 25;
        brick.position = CGPointMake(xPos, yPos);
        brick.physicsBody = [SKPhysicsBody bodyWithRectangleOfSize:brick.frame.size];
        brick.physicsBody.dynamic = NO;
        brick.physicsBody.categoryBitMask = brickCategory;


        //add bricks to scene
        [self addChild:brick];



    }
}

-(void)touchesMoved:(NSSet *)touches withEvent:(UIEvent *)event{
    for (UITouch *touch in touches) {
        CGPoint location = [touch locationInNode:self];
        CGPoint newPosition = CGPointMake(location.x, 100);


        //stop the paddle from going too far
        if (newPosition.x < self.paddle.size.width/ 2) {
            newPosition.x = self.paddle.size.width/ 2;

        }
        if (newPosition.x > self.size.width - (self.paddle.size.width/ 2)) {
            newPosition.x = self.size.width - (self.paddle.size.width/ 2);

        }
        self.paddle.position = newPosition;
    }


}


-(void) addPlayer:(CGSize)size {

    //create player paddle
    self.paddle = [SKSpriteNode spriteNodeWithImageNamed:@"paddle"];
    //resize paddle
    self.paddle.size = CGSizeMake(125, 31.25);
    //position it
    self.paddle.position = CGPointMake(size.width/2, 100);
    //add a physics body
    self.paddle.physicsBody = [SKPhysicsBody bodyWithRectangleOfSize:self.paddle.frame.size];
    //make it static
    self.paddle.physicsBody.dynamic = NO;
    self.paddle.physicsBody.categoryBitMask = paddleCategory;

    //add sprite paddle
    [self addChild:self.paddle];
}




-(instancetype)initWithSize:(CGSize)size {
    if (self = [super initWithSize:size]){
        self.backgroundColor = [SKColor colorWithRed:(29.0f/255) green:(29.0f/255) blue:(29.0f/255) alpha:1.0];

        //change gravity
        self.physicsWorld.gravity = CGVectorMake(0, 0);
        self.physicsWorld.contactDelegate = self;

        //add physics body to scene
        self.physicsBody = [SKPhysicsBody bodyWithEdgeLoopFromRect:self.frame];
        self.physicsBody.categoryBitMask = edgeCategory;


        [self addPlayer:size];
        [self addBricks:size];
        [self addBall:size];

    }
    return self;
}

@end

Answer 1

我知道发生了什么。我不小心在第一个代码片段中将非球对象声明为 bodyB，而实际上如果 bodyA.categoryBitMask 高于 bodyB.categoryBitMask，我需要让 bodyA 成为非球对象。

下面的代码就是问题所在。

-(void)didBeginContact:(SKPhysicsContact *)contact {

    //create placeholder for the "non ball" object
    SKPhysicsBody *notTheBall;
    

    
    if (contact.bodyA.categoryBitMask < contact.bodyB.categoryBitMask) {
        notTheBall = contact.bodyB;
    } else {
        notTheBall = contact.bodyB;
    }
    if (notTheBall.categoryBitMask == brickCategory) {
        NSLog(@"brick");
        [notTheBall.node removeFromParent];
    } else {
        NSLog(@"paddle");
    }
    

}

此代码已修复问题:

-(void)didBeginContact:(SKPhysicsContact *)contact {

    //create placeholder for the "non ball" object
    SKPhysicsBody *notTheBall;
    

    
    if (contact.bodyA.categoryBitMask < contact.bodyB.categoryBitMask) {
        notTheBall = contact.bodyB;
    } else {
        notTheBall = contact.bodyA;
    }
    if (notTheBall.categoryBitMask == brickCategory) {
        NSLog(@"brick");
        [notTheBall.node removeFromParent];
    } else {
        NSLog(@"paddle");
    }
    

}