Swift SpriteKit 在PhysicsBody 内部进行接触检查

Question

我正在研究PhysicsBody，但遇到了一些麻烦。首先，我现在真的不知道这是否可以通过PhysicsBody实现，或者只能通过像素检查实现。

问题是:接触检查工作得很好，但如果节点位于PhysicsBody 内部，它将无法查看它是否发生碰撞。在图片中，它得到了很好的解释。

Picture 1: This works

Picture 2: This won't

一些想法它是如何工作的？也许PhysicsBody(绿线)填充了SKNode？

这里有一些代码:(有人解释:如果人类在对象内移动并且触摸为假，则什么也没有发生，没关系，但如果人类在对象内移动并且触摸将为真，也不会发生任何事情，这是我的问题。)

    enum myContacts: UInt32 {
    case None   = 0
    case All    = 0xFFFFFFFF
    case Object  = 0b001
    case Human = 0b010
}

class whatever...{
    let Object = SKSpriteNode(imageNamed: "xyz")
    Object.position = CGPointMake(CGRectGetMidX(frame), CGRectGetMidY(frame))

    Object.physicsBody = SKPhysicsBody(circleOfRadius: Object.size.width/2)
    Object.physicsBody?.dynamic = true
    Object.physicsBody?.categoryBitMask = myContacts. Object.rawValue
    Object.physicsBody?.contactTestBitMask = myContacts.Human.rawValue
    Object.physicsBody?.collisionBitMask = 0
    Object.physicsBody?.usesPreciseCollisionDetection = true
    addChild(Object)

    let Human = SKSpriteNode(imageNamed: "zyx")
    Human.position = CGPointMake(CGRectGetMidX(frame), CGRectGetMidY(frame))

    Human.physicsBody = SKPhysicsBody(circleOfRadius: Human.size.width/2)
    Human.physicsBody?.dynamic = true
    Human.physicsBody?.categoryBitMask = myContacts. Human.rawValue
    Human.physicsBody?.contactTestBitMask = myContacts.Object.rawValue
    Human.physicsBody?.collisionBitMask = 0
    Human.physicsBody?.usesPreciseCollisionDetection = true
    addChild(Human)
}

func didBeginContact(contact: SKPhysicsContact) {
    if touched {
        let contactMask = contact.bodyA.categoryBitMask | contact.bodyB.categoryBitMask
        switch contactMask {
        case myContacts.Object.rawValue | myContacts.Human.rawValue:
            print("Human touched")
        default:
            break
        }
    }
}

override func touchesBegan(touches: Set<UITouch>, withEvent event: UIEvent?) {
    touched = true
}

override func touchesEnded(touches: Set<UITouch>, withEvent event: UIEvent?) {
    touched = false
}

Answer 1

不确定我是否完全理解您的要求，但如果您只想在节点在另一个节点“占据”的空间内生成时检测接触，则此代码将起作用:

#import "GameScene.h"

static const uint32_t playerCategory     =  0x1 << 0;
static const uint32_t obstacleCategory   =  0x1 << 1;

@interface GameScene()<SKPhysicsContactDelegate>

@property (nonatomic, strong) SKSpriteNode *player;

@property (nonatomic, strong) SKSpriteNode *obstacle;

@end

@implementation GameScene

-(void)didMoveToView:(SKView *)view {
    /* Setup your scene here */

    self.physicsWorld.contactDelegate = self;

    [self initializeNodes];


}


-(void)initializeNodes{


    self.player =  [SKSpriteNode spriteNodeWithColor:[SKColor greenColor] size:CGSizeMake(50,50)];

    self.player.name = @"player";

    self.player.position = CGPointMake(CGRectGetMidX(self.frame), CGRectGetMidY(self.frame));

    self.player.physicsBody = [SKPhysicsBody bodyWithRectangleOfSize:self.player.size];
    self.player.physicsBody.collisionBitMask = 0;
    self.player.physicsBody.categoryBitMask = playerCategory;
    self.player.physicsBody.affectedByGravity = NO;
    self.player.physicsBody.contactTestBitMask = obstacleCategory;

    self.player.zPosition = 10;

    [self addChild:self.player];


    self.obstacle =  [SKSpriteNode spriteNodeWithColor:[SKColor yellowColor] size:CGSizeMake(100,100)];

    self.obstacle.name = @"obstacle";

    self.obstacle.position = CGPointMake(CGRectGetMidX(self.frame), CGRectGetMidY(self.frame));

    self.obstacle.physicsBody = [SKPhysicsBody bodyWithRectangleOfSize:self.obstacle.size];
    self.obstacle.physicsBody.collisionBitMask = 0;
    self.obstacle.physicsBody.categoryBitMask = obstacleCategory;
    self.obstacle.physicsBody.affectedByGravity = NO;
    self.obstacle.physicsBody.contactTestBitMask = playerCategory;

    self.obstacle.zPosition = 8;

    [self addChild:self.obstacle];

}





-(void)didBeginContact:(SKPhysicsContact *)contact{
    NSLog(@"Contact detected!");
}


-(void)update:(CFTimeInterval)currentTime {
    /* Called before each frame is rendered */
}

@end

在这里，一切都非常简单:

• 我创建两个节点并为其分配物理体
• 我将这两个节点放在同一位置
• 结果，检测到了联系人

如果您复制并粘贴此代码并运行它，您将在控制台中看到一条消息:“检测到联系人”。

我猜第二张图片的情况相同(您说未检测到接触)。

此外，如果您继续移动玩家(当玩家位于障碍物范围内时)，将不会检测到进一步的接触。玩家必须先离开障碍物的边界。但是，您仍然可以检查 allContactBodies 的返回值方法返回当前 body (玩家的物理 body )所接触的 SKPhysicsBody 对象数组。