Zig zac path in sprite kit

Question

I want the sprite kit node to move 200 px to the right and 400px to left and then again 400px to right and so on until leaves the screen

    var cgpath: CGMutablePathRef = CGPathCreateMutable();

    // random values
    var xStart: CGFloat = CGFloat(0.0);
    var xEnd: CGFloat = CGFloat(0.0);

    // ControlPoint1
    var cp1X: CGFloat = CGFloat(200.0);
    var cp1Y: CGFloat = CGFloat(400.0);

    // ControlPoint2
    var cp2X: CGFloat = CGFloat(200.0);
    var cp2Y: CGFloat = CGFloat(280.0);

    var s: CGPoint = CGPointMake(xStart,-self.frame.size.height/2);
    var e: CGPoint = CGPointMake(xEnd, self.frame.size.height/2);
    var cp1: CGPoint = CGPointMake(cp1X, cp1Y);
    var cp2: CGPoint = CGPointMake(cp2X, cp2Y);
    CGPathMoveToPoint(cgpath,nil, s.x, s.y);

    CGPathAddCurveToPoint(cgpath, nil, cp1.x, cp1.y, cp2.x, cp2.y, e.x, e.y);

    var ball:SKSpriteNode = SKSpriteNode(color: UIColor.redColor(), size: CGSizeMake(40, 40));

    var followTrack = SKAction.followPath(cgpath, asOffset: false, orientToPath: true, duration: 15.0);
    var forever: SKAction = SKAction.repeatActionForever(followTrack);
    ball.runAction(forever);
    self.addChild(ball);

    let shapeNode = SKShapeNode(path: cgpath)
    self.addChild(shapeNode);

Answer 1

Try the following code to get a zig zag path using bezier curves.

var cgpath: CGMutablePathRef = CGPathCreateMutable();

var xStart: CGFloat = CGFloat(200.0);
var xEnd: CGFloat = CGFloat(200.0);

var yStart : CGFloat = 0
var yEnd : CGFloat = self.size.height

let numberOfIntermediatePoints  = 10
let xOffset : CGFloat = 400
let intervalY = (yEnd - yStart)/CGFloat(numberOfIntermediatePoints)

var s: CGPoint = CGPointMake(xStart,yStart);
CGPathMoveToPoint(cgpath,nil, s.x, s.y);


for i in stride(from: 0, through: numberOfIntermediatePoints - 1, by: 1) {

    let yOff = intervalY * CGFloat(i) + yStart
    let controlPointInterval = intervalY/3

    var cp1X: CGFloat = CGFloat(xStart + xOffset);
    var cp1Y: CGFloat = CGFloat(yStart + yOff + controlPointInterval);

    var cp2X: CGFloat = CGFloat(xStart - xOffset);
    var cp2Y: CGFloat = CGFloat(yStart + yOff + controlPointInterval * 2);

    var e: CGPoint = CGPointMake(xEnd, yStart + yOff + intervalY);
    var cp1: CGPoint = CGPointMake(cp1X, cp1Y);
    var cp2: CGPoint = CGPointMake(cp2X, cp2Y);

    CGPathAddCurveToPoint(cgpath, nil, cp1.x, cp1.y, cp2.x, cp2.y, e.x, e.y);

}

var ball:SKSpriteNode = SKSpriteNode(color: UIColor.redColor(), size: CGSizeMake(40, 40));

var followTrack = SKAction.followPath(cgpath, asOffset: false, orientToPath: true, duration: 5.0);
var forever: SKAction = SKAction.repeatActionForever(followTrack);
ball.runAction(forever);
self.addChild(ball);

let shapeNode = SKShapeNode(path: cgpath)
self.addChild(shapeNode);

Change numberOfIntermediatePoints and xOffset values to change the number of zig zags and the amount of distance moved in each zig zag.