Changing x position of SKSpriteNode

cyril Published at Dev

Cyril

I am running a for loop in my game that would generate SKSpriteNodes.

I want my first block to start at (20, 40) and add 20 to the x position and 40 to the y position for every new block.

First block (20, 40) Second block (40, 80) Third Block (60, 120) And so on.

The y position is behaving the way I want to, however the x position would randomly start anywhere on my screen then add 20 for every new block generated.

Below is my code.

       func generateBlocks() {

            for _ in 1..<5 {

                xP += 20
                yP += 40

                let xx = CGFloat (xP)
                let yy = CGFloat (yP)

                print("x position: \(xx)")
                print("y position: \(yy)")

                let resourcePath = NSBundle.mainBundle().pathForResource("Blocks", ofType: "sks")
                let blocks = MSReferenceNode(URL: NSURL (fileURLWithPath: resourcePath!))

                blocks.goals.position = CGPoint (x: xx,y: yy)
                addChild(blocks)
    }

    }

I also added the print statement of how it would look like when I run the code.

Below is the print statement of the x and y positions of the blocks.

I tried switching the order of the xP and yP initializing. That didn't work.

Any suggestions?

Alessandro Ornano

I would prefer to use while loops for this kind of operations where you must impose a condition from start, for example limits:

class GameScene: SKScene {
    let deltaX:CGFloat = 20.0
    let deltaY:CGFloat = 40.0
    override func didMoveToView(view: SKView) {
        let widthLimit = self.frame.width-40
        let heightLimit = self.frame.height-140
        let startX:CGFloat = 80.0
        drawStair(startX,limits:CGSizeMake(widthLimit,heightLimit))
    }
    func drawStair(startFromX:CGFloat,limits:CGSize) {
        var currentX:CGFloat = startFromX
        var currentY:CGFloat = startFromX+deltaY
        while currentX<limits.width && currentY<limits.height {
            drawBlock(CGPointMake(currentX,currentY))
            currentX += deltaX
            currentY += deltaY
        }
    }
    func drawBlock(position: CGPoint,size:CGSize = CGSizeMake(40,40)) {
        let block = SKSpriteNode(color: UIColor.redColor(), size: size)
        block.position = position
        block.name = "block"
        addChild(block)
    }
}

Output: