Swift 3 (SpriteKit): Aligning SKPhysicsBody to SKShapeNode

Question

I am creating SKShapeNodes in my program using this:

let points = [CGPoint(x: x, y: y), CGPoint(x: x2, y: y2)]
let line = SKShapeNode(points: &points, count: points.count)

The problem that I am having is that whenever I add a physicsBody to the line, the physicsBody is not aligned with the line. I realise that the issue is because the line's position is always CGPoint(x: 0, y: 0) so the physicsBody is always in the centre of the screen regardless of where the line is. Here is my code for creating the physicsBody:

line.physicsBody = SKPhysicsBody(rectangleOf: (line.frame.size))

If anyone knows how to align the physicsBody to the line, then please reply with your solution. Thanks!

Answer 1

If you want to make a physics body from one point to the other, you may use something like this:

class GameScene:SKScene {

    override func didMove(to view: SKView) {
        var points = [CGPoint(x: 22, y: 22), CGPoint(x: 155, y: 155)]
        let line = SKShapeNode(points: &points, count: points.count)
        print(line.frame.size)

        line.physicsBody = SKPhysicsBody(edgeFrom: points[0], to: points[1])

        addChild(line)
    }
}

This will create an edge based physics body using two points. An edge physics body is static by default so keep that in mind. To register a contact (or make a collision with this body) the other body has to be dynamic.

If you want to have this body dynamic, then look for volume based initializers.