Question

我想在SpriteKit中覆盖碰撞。

我的想法是，我有一个球在场景周围反弹。当didBeginContact检测到边缘和球之间的接触时，我希望球以随机方向和速度反弹。

import SpriteKit


class GameScene: SKScene, SKPhysicsContactDelegate {

let kEdgeCollisionCategory:UInt32 = 0x1 << 1
let kSquareCollisionCategory:UInt32 = 0x1 << 2

override func didMoveToView(view: SKView) {
    /* Setup your scene here */

    // Physics world
    self.physicsWorld.gravity = CGVectorMake(0.0, 0.0)
    self.physicsWorld.contactDelegate = self       

    // Edge
    let frameEdges = SKNode()
    frameEdges.physicsBody = SKPhysicsBody(edgeLoopFromRect: self.frame)
    frameEdges.physicsBody?.categoryBitMask = kEdgeCollisionCategory
    self.addChild(frameEdges)

// Sprite
    var sprite = SKSpriteNode(imageNamed: "blue")
    sprite.physicsBody = SKPhysicsBody(rectangleOfSize: CGSizeMake(sprite.size.width, sprite.size.height))
    sprite.physicsBody?.restitution = 1.0
    sprite.physicsBody?.linearDamping = 0.0
    sprite.physicsBody?.angularDamping = 0.0
    sprite.physicsBody?.friction = 0.0
    sprite.physicsBody?.dynamic = true
    sprite.physicsBody?.categoryBitMask = kSquareCollisionCategory
    sprite.physicsBody?.collisionBitMask = kEdgeCollisionCategory
    sprite.physicsBody?.contactTestBitMask = kEdgeCollisionCategory
    self.addChild(sprite)
}



func didBeginContact(contact: SKPhysicsContact) {

    var firstBody:SKPhysicsBody?
    var second:SKPhysicsBody?


    if (contact.bodyA.categoryBitMask < contact.bodyB.categoryBitMask) {
        firstBody = contact.bodyA
        secondBody = contact.bodyB
    }
    else {
        firstBody = contact.bodyB
        secondBody = contact.bodyA
    }

    var randomX = CGFloat(arc4random_uniform(UInt32(4))))
    var randomY = CGFloat(arc4random_uniform(UInt32(4))))

    if firstBody!.categoryBitMask == kSquareCollisionCategory && secondBody!.categoryBitMask == kEdgeCollisionCategory {
        firstBody!.velocity = (CGVectorMake(firstBody!.velocity.dx * randomX, firstBody!.velocity.dy * randomY))
    }

}

}

Answer 1

接触后，您可以根据球的当前矢量向球施加力或冲击力。例如，在接触球时，球的矢量是（30，-20）。此示例向量转换为向右和向下移动的球。然后，您可以应用一个新的矢量，使球向左和向上移动（-20,25）。您可以使用arc4random设置新值或设置静态值。

如果您需要，请阅读物理机构using vectors。

Answer 2

你的问题在这里，

 if (contact.bodyA.categoryBitMask < contact.bodyB.categoryBitMask) {
    firstBody = contact.bodyA
    secondBody = contact.bodyB
}
else {
    firstBody = contact.bodyB
    secondBody = contact.bodyA
}

这意味着第一个主体具有kEdgeCollisionCategory的categoryBitMask，第二个主体具有kSquareCollisionCategory的categoryBitMask。所以改成这个，

 if (contact.bodyA.categoryBitMask < contact.bodyB.categoryBitMask) {
    firstBody = contact.bodyB
    secondBody = contact.bodyA
}
else {
    firstBody = contact.bodyA
    secondBody = contact.bodyB
}

要获得随机数，请使用

int minSpeed = 1;
int maxSpeed = 20;
int randNum = rand() % (max-min) + min;

然后对所需的身体施加冲动。

覆盖SpriteKit中的冲突

2 个答案: