I am creating a game and I need a set of poles to move from the right side of the screen to the left. once it gets to the left, I need to reset the poles to the beginning and go again in a continuous loop. Create poles simply sets the x position of both poles to the original starting position. The poles move just fine the problem is the looping aspect. I am not sure why the code below will not work. I am very new to swift and admit I am not too sure what I am doing.
movePole()
let create = SKAction.run {
() in
self.createPoles()
self.movePole()
}
let delay = SKAction.wait(forDuration: 10)
let spawn = SKAction.sequence([create,delay])
self.run(SKAction.repeatForever(spawn))
Here's what you need to do:
Tell the poles to move a specific distance for a duration.
Tell the poles to move back to the start point.
Repeat.
As demonstrated here:
let AnimationTime = 5
let PoleTravelDistance = view.frame.width
let MovePolesToLeft = SKAction.move(by: CGVector(dx: PoleTravelDistance, dy: 0), duration: AnimationTime)
let ReturnPolesToRight = SKAction.move(to: CGPoint(x: (POLESNODE.frame.width)/2, y: (POLESNODE.position.y)), duration: 0)
let PoleAnimationSequence = SKAction.sequence([MovePolesToLeft, ReturnPolesToRight])
POLESNODE.run(SKAction.repeatForever(PoleAnimationSequence))
Hope that helps.
Related
I am attempting to generate a random X position for a simple object, in order to have it bounce back and forth inside the scene in a Swift SpriteKit game. The repeatForever action should generate a random value and then move the object (a circle) multiple times to different locations, left and right. However, it acts only one time. It is as if the random function, which works correctly, is called only one time, and the action then simply continues to move the object to the same position forever.
let circle = SKSpriteNode(imageNamed: "circle")
circle.run(SKAction.repeatForever(SKAction.move(to:
CGPoint(x: random(min: minCircleX, max: maxCircleX),
y: scene.size.height*0.5),
duration: 0.5)))
The circle moves only one time, to one position, and never seems to be moved after that. I suspect it is simply moving to the same position over and over. Thanks for any suggestions!
OK, after multiple efforts, the following works:
let customAction = SKAction.customAction(withDuration: 1000)
{
circle, _ in
let newXLocation: CGPoint = CGPoint(x: random(min: minCircleX, max: maxCircleX),
y: scene.size.height*0.5)
circle.run(SKAction.move(to: newXLocation, duration: 0.5))
}
circle.run(customAction)
Dai was correct in suggesting an anonymous function. The SKAction method customAction allows for that. And then running the actual action inside the function insured that the movement was random every time. Thanks so much!
Instead of repeat forever, use the completionblock to establish a new moveTo:
func newLocation(){
let newXLocation: CGPoint = CGPoint(x: random(min: minCircleX, max: maxCircleX),
y: scene.size.height*0.5)
circle.run(SKAction.move(to: newXLocation, duration: 0.5){
[weak self] in self?.newLocation()
}
}
What this does is upon finishing the moveTo, it will add a new moveTo and the next random location. The only "flaw" is it will start the next move during the same frame as the current move since this is being done in the action phase of the update. If you do not want this effect, then you need to store it in a block to be done during didFinishUpdate
var finishedUpdates = [()->()]()
func newLocation(){
let newXLocation: CGPoint = CGPoint(x: random(min: minCircleX, max: maxCircleX),
y: scene.size.height*0.5)
circle.run(SKAction.move(to: newXLocation, duration: 0.5){
[weak self] in
self?.finishedUpdates.append({weak self] in self?.newLocation()})
}
}
func didFinishUpdate()
{
finishedUpdates.forEach{$0()}
finishedUpdates = [()->()]() //Be sure to clear the array
}
My apologies in advance, this is written from memory alone, and may not be 100% syntactically correct
I have a blue sky texture moving from the top of the screen to the bottom, repeating forever in a function. However, when touches begin, I would like the blue sky to completely fade out after a duration, then completely remove from the scene.
I am able to get the sky to fade out momentarily, then it seems as though half of the loop is removed, but I still get the sky coming down every other time. Here's a video of the problem: Blue Sky Video
In the video, touches begin when the pause button appears at the top left of the screen - before touches begin, the blue sky moves from top to bottom seamlessly as it should.
FUNCTION
func createBlueSky() {
let blueSkyTexture = SKTexture(imageNamed: "blueSky")
for i in 0 ... 1 {
let blueSky = SKSpriteNode(texture: blueSkyTexture)
blueSky.name = "blueSky"
blueSky.zPosition = -60
blueSky.anchorPoint = CGPoint.zero
blueSky.position = CGPoint(x: 0, y: (blueSkyTexture.size().height * CGFloat(i)))
worldNode.addChild(blueSky)
let moveDown = SKAction.moveBy(x: 0, y: -blueSkyTexture.size().height, duration: 10)
let moveReset = SKAction.moveBy(x: 0, y: blueSkyTexture.size().height, duration: 0)
let moveLoop = SKAction.sequence([moveDown, moveReset])
let moveForever = SKAction.repeatForever(moveLoop)
blueSky.run(moveForever)
}
}
I've added the above function to didMove(toView)
override func didMove
createBlueSky()
Then in my touches began I added this code to fade out and remove from parent.
I saw in another post that to access the blue sky from another function, I'd need to give it a name, which I did. Still no luck :/
override func touchesBegan
let blueSky = worldNode.childNode(withName: "blueSky") as! SKSpriteNode
let blueSkyFade = SKAction.fadeOut(withDuration: 3)
let blueSkyFadeWait = SKAction.wait(forDuration: 3)
let removeBlueSky = SKAction.removeFromParent()
blueSky.run(SKAction.sequence([blueSkyFadeWait, blueSkyFade, removeBlueSky]))
I'm very new to Swift, but I hope the question was specific enough. I'm happy to provide any other necessary information.
You are creating 2 blueSky nodes, but you only fade and remove 1 of them. You need to enumerate through all of the nodes with the name you are looking for. To do this, you call enumerateChildNodes(withName:}
let blueSkyFade = SKAction.fadeOut(withDuration: 3)
let blueSkyFadeWait = SKAction.wait(forDuration: 3)
let removeBlueSky = SKAction.removeFromParent()
enumerateChleNodes(withName:"blueSky")
{
(blueSky,stop) in
blueSky.run(SKAction.sequence([blueSkyFadeWait, blueSkyFade, removeBlueSky]))
}
I'm trying to make a sprite "comet" appear at a random position at random times. So far, I wanted to test if my random position code works, however, I can't seem to even see the sprite. This is my code:
func spawnAtRandomPosition() {
let height = self.view!.frame.height
let width = self.view!.frame.width
let randomPosition = CGPointMake(CGFloat(arc4random()) % height, CGFloat(arc4random()) % width)
let sprite = SKSpriteNode(imageNamed: "comet")
sprite.position = randomPosition
self.addChild(sprite)
}
As I said, I'm not seeing anything. Any help? If you already know how to make it appear at a random time that would be appreciated as well, because that's having problems of its own, however this is my focus right now. Thanks!
Your code for setting the random position is incorrect. Additionally, your code has issues that should make it impossible to compile in Swift 3. Your full function should look like this:
func spawnAtRandomPosition() {
let height = UInt32(self.size.height)
let width = UInt32(self.size.width)
let randomPosition = CGPoint(x: Int(arc4random_uniform(width)), y: Int(arc4random_uniform(height)))
let sprite = SKSpriteNode(imageNamed: "comet")
sprite.position = randomPosition
self.addChild(sprite)
}
Note the changes to randomPosition and the height and width:
let randomPosition = CGPoint(x: Int(arc4random_uniform(width)), y: Int(arc4random_uniform(height)))
This determines a random value between 0 and your width and does the same thing for the height.
As for the height and width, see #Whirlwind's comment on the question explaining the difference between the view and the scene.
Additionally, you may want to check if you're setting up your node properly (set size, try with fixed location, etc) before you test the random positioning, to determine where the problem truly lies.
I came up with this bit of code and it works for me:
let randomNum = CGPoint(x:Int (arc4random() % 1000), y: 1)
let actionMove = SKAction.moveTo(randomNum, duration: 1)
I only wanted the x to be randomized, however if you need "y" to be randomized as well, you can just copy the specification to x to y.
The movement of a physics body circle is too erratic for what I want to achieve. I would like to restrict it so it follows a certain path touching specific points (or a range of points) as shown in the image below. How can I set the physics properties to traverse a similar path?
how to set physics properties for a circle so it follows given path
So essentially you are looking to move a node to a particular point using real-time motion. I have an answer here showing how to do this, however given the number of up votes this question has received, I will provide a more detailed answer.
What the answer I linked to doesn't provide is traversing a path of points. So below I have provided a solution showing how this can be done below. It simply just moves to each point in the path, and each time the node reaches a point, we increment the index to move to the next point. I also added a few variables for travel speed, rate (to make the motion more smooth or static) and whether or not the node should repeat the path. You could further expand upon this solution to better meet the needs of your game. I would definitely consider subclassing a node and building this behavior into it so you can re-use this motion for multiple nodes.
One final note, you may notice the calculation for the impulse varies between my solution below and the answer I linked to above. This is because I am avoiding using angle calculation because they are very expensive. Instead I am calculating a normal so that the calculation is more computationally efficient.
One final note, my answer here explains the use of the rate factor to smooth the motion and leave room for motion distortions.
import SpriteKit
class GameScene: SKScene {
var node: SKShapeNode! //The node.
let path: [CGPoint] = [CGPoint(x: 100, y: 100),CGPoint(x: 100, y: 300),CGPoint(x: 300, y: 300),CGPoint(x: 300, y: 100)] //The path of points to travel.
let repeats: Bool = true //Whether to repeat the path.
var pathIndex = 0 //The index of the current point to travel.
let pointRadius: CGFloat = 10 //How close the node must be to reach the destination point.
let travelSpeed: CGFloat = 200 //Speed the node will travel at.
let rate: CGFloat = 0.5 //Motion smoothing.
override func didMoveToView(view: SKView) {
node = SKShapeNode(circleOfRadius: 10)
node.physicsBody = SKPhysicsBody(circleOfRadius: 10)
node.physicsBody!.affectedByGravity = false
self.addChild(node)
}
final func didReachPoint() {
//We reached a point!
pathIndex++
if pathIndex >= path.count && repeats {
pathIndex = 0
}
}
override func update(currentTime: NSTimeInterval) {
if pathIndex >= 0 && pathIndex < path.count {
let destination = path[pathIndex]
let displacement = CGVector(dx: destination.x-node.position.x, dy: destination.y-node.position.y)
let radius = sqrt(displacement.dx*displacement.dx+displacement.dy*displacement.dy)
let normal = CGVector(dx: displacement.dx/radius, dy: displacement.dy/radius)
let impulse = CGVector(dx: normal.dx*travelSpeed, dy: normal.dy*travelSpeed)
let relativeVelocity = CGVector(dx:impulse.dx-node.physicsBody!.velocity.dx, dy:impulse.dy-node.physicsBody!.velocity.dy);
node.physicsBody!.velocity=CGVectorMake(node.physicsBody!.velocity.dx+relativeVelocity.dx*rate, node.physicsBody!.velocity.dy+relativeVelocity.dy*rate);
if radius < pointRadius {
didReachPoint()
}
}
}
}
I did this pretty quickly so I apologize if there is a mistake. I don't have time now but I will add a gif showing the solution later.
A note about collisions
To fix the erratic movement during a collision, after the 2 bodies collide set the "rate" property to 0 or preferably a very low number to reduce the travel velocity impulse which will give you more room for motion distortion. Then at some point in the future (maybe some time after the collision occurs or preferably when the body is moving slow again) set the rate back to its initial value. If you really want a nice effect, you can actually ramp up the rate value over time from 0 to the initial value to give yourself a smooth and gradual acceleration.
Quick implementation using followPath:duration:
override func didMoveToView(view: SKView) {
self.backgroundColor = UIColor.blackColor()
let xWidth: CGFloat = CGRectGetMaxX(self.frame)
let yHeight: CGFloat = CGRectGetMaxY(self.frame)
let ball = SKSpriteNode(color: UIColor.redColor(), size: CGSizeMake(50.0, 50.0))
let offset : CGFloat = ball.size.width / 2
// Moving path
let path = CGPathCreateMutable()
CGPathMoveToPoint(path, nil, offset, yHeight / 2)
CGPathAddLineToPoint(path, nil, xWidth * 2 / 3, yHeight - offset)
CGPathAddLineToPoint(path, nil, xWidth - offset, yHeight * 2 / 3)
CGPathAddLineToPoint(path, nil, xWidth / 2, offset)
CGPathAddLineToPoint(path, nil, offset, yHeight / 2)
// Movement
let moveByPath = SKAction.followPath(path, asOffset: false, orientToPath: false, duration: 4.0)
let moveForever = SKAction.repeatActionForever(moveByPath)
ball.runAction(moveForever)
self.addChild(ball)
}
In GameViewController.swift, I changed the default GameScene.unarchiveFromFile method to let scene = GameScene(size: view.bounds.size) for creating the scene's size.
Preview:
Is there a way to change the velocity/speed of a skaction and also to reset the skaction?
let wait = SKAction.waitForDuration(5.0)
let moveRight = SKAction.moveByX(300, y:0, duration: 1.0)
let sequence = SKAction.sequence([wait, moveRight])
let endlessAction = SKAction.repeatActionForever(sequence)
node.runAction(endlessAction)
This code works but the things i would like to change is how fast the SKSpriteNode moves to the right as at the moment it it quite slow and also to make the SKSpriteNode return to its orignal position rather than keep on moving to right forever?
Thank you
Since velocity = distance / time, decreasing the duration will increase the speed the the sprite will move across the screen.
Regarding your second point, by considering how SKAction.moveByX(300, y:0, duration: 1.0) moves the node to the right; SKAction.moveByX(-300, y:0, duration: 1.0) must therefore move the node to the left, back to its original position.
Hope that helps.