How To Have Character Slide Back and Forth Automatically and Infinitely? - ios

Question

I'm an ubernoob developing a game using SpriteKit from scratch and im trying to make a character that will slide back and forth off the sides of the screen (in landscape mode) until collision is detected with another node (that I will add later). Think of pong and how the paddle can move side to side except I want that movement to be completely automatic/infinite.
Side Note: I plan on having this character jump when the screen is touched but continue with the back and forth movement. idk if that makes a difference in your approach.

Answer 1

Ok, so this answer isn't perfect but it's working for me right now so:
basically you touch the screen to spawn a boxd, and when the paddle touches the box some stuff happens (it stops moving):
import SpriteKit
// constants!
class GameScene: SKScene, SKPhysicsContactDelegate {
// A little complicated, but basically we want to have a constant speed across all screen sizes
var sliderSpeed: CGFloat { return self.size.width / 3 }
var slider = SKSpriteNode()
var sliderVelocity = CGFloat(0)
var sliderIsContacted = false
let boxMask = UInt32(2)
let sliderMask = UInt32(4)
// For use to contact slider
func spawnBox(at pos: CGPoint) {
let rect = CGRect(origin: CGPoint.zero, size: CGSize(width: 45, height: 45))
let shape = SKShapeNode(rect: rect)
shape.fillColor = .green
shape.position = pos
let pb = SKPhysicsBody(rectangleOf: rect.size)
pb.categoryBitMask = boxMask
pb.contactTestBitMask = sliderMask
shape.physicsBody = pb
addChild(shape)
}
func setupSlider() {
sliderVelocity = sliderSpeed
let rect = CGRect(origin: CGPoint.zero, size: CGSize(width: 45, height: 10))
let shape = SKShapeNode(rect: rect)
shape.fillColor = .blue
let pb = SKPhysicsBody(rectangleOf: rect.size)
pb.categoryBitMask = sliderMask
pb.contactTestBitMask = boxMask
pb.velocity.dx = sliderVelocity // moves our slider to the right!
// A little complicated, but basically we want to have a spritenode, not a shapenode:
slider = SKSpriteNode(texture: view!.texture(from: shape))
slider.physicsBody = pb
addChild(slider)
}
func setupWorld() {
let pb = SKPhysicsBody(edgeLoopFrom: frame)
pb.categoryBitMask = UInt32(0)
self.physicsBody = pb
physicsWorld.contactDelegate = self
physicsWorld.gravity = CGVector.zero
}
override func didMove(to view: SKView) {
setupSlider()
setupWorld()
}
}
// Game loop:
extension GameScene {
// touchesBegan in iOS:
override func mouseDown(with event: NSEvent) {
let location = event.location(in: self)
spawnBox(at: location)
}
override func update(_ currentTime: TimeInterval) {
let sliderPB = slider.physicsBody!
let halfWidth = slider.size.width/2
// move slider left when it reaches far right border:
if sliderPB.velocity.dx > 0 {
if slider.position.x >= (frame.maxX - halfWidth) {
sliderVelocity = -sliderSpeed
}
}
// move slider right when it reaches far left border:
else {
if slider.position.x <= (frame.minX + halfWidth) {
sliderVelocity = sliderSpeed
}
}
// Keep slider at constant rate:
if sliderIsContacted == false {
sliderPB.velocity.dx = sliderVelocity
}
}
func didBegin(_ contact: SKPhysicsContact) {
if contact.bodyA.categoryBitMask + contact.bodyB.categoryBitMask == sliderMask + boxMask {
sliderIsContacted = true
slider.physicsBody!.velocity.dx = 0 // stop slider
}
}
}
more complicated than it shoudl be, but I"m sdrunk so this is what I got :)
}hope it helps.