Rotate a sprite to sprite position not exact in SpriteKit with Swift

Question

I\'m trying to rotate a player to the touch. Using the touches move function, I set the location to a variable. I then call a function. It works but the angle is off. Locati

Answer 1

Use an orientation constraint to rotate your object to the touch position:

// Create two global Sprite properties:

var heroSprite = SKSpriteNode(imageNamed:"Spaceship")
var invisibleControllerSprite = SKSpriteNode()

override func didMoveToView(view: SKView) {         

   // Create the hero sprite and place it in the middle of the screen
   heroSprite.xScale = 0.15
   heroSprite.yScale = 0.15
   heroSprite.position = CGPointMake(self.frame.width/2, self.frame.height/2)
   self.addChild(heroSprite)

   // Define invisible sprite for rotating and steering behavior without trigonometry
   invisibleControllerSprite.size = CGSizeMake(0, 0)
   self.addChild(invisibleControllerSprite)

   // Define a constraint for the orientation behavior
   let rangeForOrientation = SKRange(constantValue: CGFloat(M_2_PI*7))

   heroSprite.constraints = [SKConstraint.orientToNode(invisibleControllerSprite, offset: rangeForOrientation)]

}

override func touchesBegan(touches: NSSet, withEvent event: UIEvent) {
    /* Called when a touch begins */        
    for touch: AnyObject in touches {

        // Determine the new position for the invisible sprite:
        // The calculation is needed to ensure the positions of both sprites 
        // are nearly the same, but different. Otherwise the hero sprite rotates
        // back to it's original orientation after reaching the location of 
        // the invisible sprite
        var xOffset:CGFloat = 1.0
        var yOffset:CGFloat = 1.0
        var location = touch.locationInNode(self)
        if location.x>heroSprite.position.x {
            xOffset = -1.0
        }
        if location.y>heroSprite.position.y {
            yOffset = -1.0
        }

        // Create an action to move the invisibleControllerSprite. 
        // This will cause automatic orientation changes for the hero sprite
        let actionMoveInvisibleNode = SKAction.moveTo(CGPointMake(location.x - xOffset, location.y - yOffset), duration: 0.2)
        invisibleControllerSprite.runAction(actionMoveInvisibleNode)

        // Optional: Create an action to move the hero sprite to the touch location
        let actionMove = SKAction.moveTo(location, duration: 1)
        heroSprite.runAction(actionMove)

    }

}

Tutorial: http://stefansdevplayground.blogspot.de/2014/11/how-to-implement-space-shooter-with.html

Video: https://youtu.be/8d8MH_gXt84