(Swift SpriteKit) Rotate the sprite in the direction of touch

Question

In the screenshot, the red arrow and cross are for demonstration purposes only and are not in the game. I would like the sprite of the spacecraft to be directed towards the ball that it is shooting.

Image link

Here is my current code for touch location

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

    for touch in touches {
        let location = touch.locationInNode(self)

        var bullet = SKSpriteNode(imageNamed: "bullet")
        bullet.position = cannon.position
        bullet.size = CGSize(width: 35, height: 35)

        //physics
        bullet.physicsBody = SKPhysicsBody(circleOfRadius: bullet.size.width/2)
        bullet.physicsBody?.categoryBitMask = PhysicsCategory.bullet
        bullet.physicsBody?.collisionBitMask = PhysicsCategory.enemy
        bullet.physicsBody?.contactTestBitMask = PhysicsCategory.enemy
        bullet.name = "bullet"
        bullet.physicsBody?.affectedByGravity = false

        self.addChild(bullet)

        var dx = CGFloat(location.x - cannon.position.x)
        var dy = CGFloat(location.y - cannon.position.y)

        let magnitude = sqrt(dx * dx + dy * dy)

        dx /= magnitude
        dy /= magnitude

        let vector = CGVector(dx: 120.0 * dx, dy: 120.0 * dy) //adjust constant to increase impluse.

        bullet.physicsBody?.applyImpulse(vector)

        // I found this code bellow this comment, but it just moves the cannon y position

        let direction = SKAction.moveTo(
            CGPointMake(
                400 * -cos(bullet.zRotation - CGFloat(M_PI_2)) + bullet.position.x,
                400 * -sin(bullet.zRotation - CGFloat(M_PI_2)) + bullet.position.y
            ),
            duration: 0.8)

        cannon.runAction(direction)
    }
}

Answer 1

I worked some time ago in something like what you want so much, here are my results

first you need to use VectorMath.swiftcreated by Nick Lockwood and this is my code to make my spider move to user touch

import SpriteKit
import SceneKit

class GameScene: SKScene {
    let sprite = SKSpriteNode(imageNamed:"Aranna")
    var velocity = Vector2(x: 0, y: 0)
    var positionV2D = Vector2(x: 0, y: 0)
    var headingVector = Vector2(x: 0, y: 1)

    override func didMoveToView(view: SKView) {
        /* Setup your scene here */
        let myLabel = SKLabelNode(fontNamed:"Chalkduster")
        myLabel.text = "Hello, World!";
        myLabel.fontSize = 45;
        myLabel.position = CGPoint(x:CGRectGetMidX(self.frame), y:CGRectGetMidY(self.frame));

        sprite.position = CGPoint(x:CGRectGetMidX(self.frame), y:CGRectGetMidY(self.frame));
        positionV2D = Vector2(point:sprite.position);

        let testVector = Vector2(x: 10, y: 14);
        velocity += testVector;
        print(velocity.toString());
        velocity += Vector2(x: 1, y: 1);
        //velocity = velocity + testVector;
        print(velocity.toString());
        velocity *= 0.5;
        velocity.printVector2D();

        velocity = Vector2(x: 2, y: 2);
        velocity.normalized();
        velocity.printVector2D();

        self.addChild(sprite)
    }


    func ToRad(grados:CGFloat) ->CGFloat
    {
        return ((CGFloat(M_PI) * grados) / 180.0)
    }

    func ToDeg(rad:CGFloat) ->CGFloat
    {
        return (180.0 * rad / CGFloat(M_PI))
    }

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

        for touch in touches {
            let location = touch.locationInNode(self)

            let toTarget = Vec2DNormalize(Vector2(point:location) - positionV2D);


            let angle2 = headingVector.angleWith(toTarget);

            print(ToDeg(CGFloat(angle2)));

            headingVector.printVector2D();

            self.sprite.runAction(SKAction.rotateToAngle(CGFloat(angle2), duration: 0.1))
            self.sprite.runAction(SKAction.moveTo(location, duration: 0.5))
            positionV2D = Vector2(point: location);

        }
    }

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

Hope this helps you.

Answer 2

, , .

, SpriteKit Swift

 let angle = atan2(location.y - cannon.position.y , location.x - cannon.position.x)
 cannon.zRotation = angle - CGFloat(M_PI_2)

Answer 3

, moveTo. rotateToAngel

        let angle = atan2(dy, dx) - CGFloat(M_PI_2)
        let direction = SKAction.rotateToAngle(angle, duration: 0.4, shortestUnitArc: true)
        cannon.runAction(direction)

Answer 4

, , , , - , , , ,

 let angle = atan2(touchlocation.x - cannon.position.x , touchlocation.y - 
 cannon.position.y)
 cannon.zRotation = -(angle - CGFloat(Double.pi/2))

Double.pi/2 M_PI_2