How to make sprite sit on a moving sprite

问题

How to make a sprite sit on a moving sprite and travel with it. I have made the red box jump with impulse and when it falls on the black block down which is moving, the red box stays were it dropped slips the moving object like there is no friction. Conditions gravity on, friction 1.0 in both even tried increasing the mass, but nothing worked. Please give me any details how to make it work ? thanks override func didMoveToView(view: SKView) { /* Setup your scene here */

    self.physicsWorld.gravity = CGVectorMake(0.0, -9.8)
    SquareOne.fillColor = UIColor.orangeColor()
    SquareOne.position = CGPoint(x: self.frame.midX, y: self.frame.midY)
    SquareOne.physicsBody = SKPhysicsBody(rectangleOfSize: SquareOne.frame.size)
    SquareOne.physicsBody?.friction = 1.0
    SquareOne.physicsBody?.restitution = 0.0

    addChild(SquareOne)


    SquareTwo.fillColor = UIColor.greenColor()
    SquareTwo.position = CGPoint(x: self.frame.midX, y: self.frame.midY - 100)
    SquareTwo.physicsBody = SKPhysicsBody(rectangleOfSize: SquareTwo.frame.size)
    SquareTwo.physicsBody?.dynamic = false
    SquareTwo.physicsBody?.affectedByGravity = false
    SquareTwo.physicsBody?.friction = 1.0
    SquareTwo.physicsBody?.restitution = 0.0
    addChild(SquareTwo)

}

override func touchesBegan(touches: Set<NSObject>, withEvent event: UIEvent) {
    /* Called when a touch begins */

    for touch in (touches as! Set<UITouch>) {
        let location = touch.locationInNode(self)
        SquareTwo.runAction(SKAction.moveByX(-100, y: 0.0, duration: 3.0))
    }
}

回答1:

In a physics simulation, you should apply velocity and forces for the simulation to work correctly. Physics cannot be simulated correctly using SKAction.

First the SquareTwo needs to be made dynamic for it to be effected by forces. Make the mass of SquareTwo big so that the body is not affected by the other SquareOne colliding with it.

SquareTwo.physicsBody?.dynamic = true
SquareTwo.physicsBody?.affectedByGravity = false
// Make the mass big so that the body is not affected by the other body colliding with it.
SquareTwo.physicsBody?.mass = 1000000

Then inside touchesBegan you can set a velocity to SquareTwo

override func touchesBegan(touches: Set<NSObject>, withEvent event: UIEvent) {
    /* Called when a touch begins */

    for touch in (touches as! Set<UITouch>) {
        let location = touch.locationInNode(self)
        SquareTwo.physicsBody?.velocity = CGVectorMake(-10, 0)
     }
}

回答2:

You can remove the red block then add it as a child node to the moving block:

var redBlockPosition = childNodeWithName("redBlockName")?.position //find where red block is in self
var movingBlockPosition = childNodeWithName("movingBlockName")?.position //find where moveing block is in self
var redBlockPositionFromMovingBlock = CGPointMake(redBlockPosition.x + movingBlockPosition.x, redBlockPosition.y - movingBlockPosition.y) //find where red block is from moving block's origin
childNodeWithName("redBlockName")?.removeFromParent() //remove red block
redBlock.position = redBlockPositionFromMovingBlock //change redBlock's position
childNodeWithName("movingBlockName")?.addChild(redBlock) //add red block as a child node of moving block

Hope this helped and good luck.

回答3:

Try redBox.physicsBody.allowsRotation = NO,

A Boolean value that indicates whether the physics body is affected by angular forces and impulses applied to it.

And adjust redBox.physicsBody.restitution between 0.0 to 1.0,

The bounciness of the physics body.

来源：https://stackoverflow.com/questions/32513802/how-to-make-sprite-sit-on-a-moving-sprite

标签

swift

sprite-kit