I create an game that include balls that has gravity and restitution properties (every ball has different properties by random function). now I want to detect the last position of each ball and then call a remove from node function. Im using the update function to detected the position of the ball while its jumping on the screen. im not sure if I can and how can I detect its last position. Im thinking about create an array that will store each position but I not sure if its right way and wonder if there is a simpler and better way.
here is my code for now:
override func update(_ currentTime: TimeInterval) {
self.enumerateChildNodes(withName: "BALL") { (node:SKNode, nil) in
print(node.position)
}
}
can you help me with that? the array option is only way or there is another one and better one?
You could subclass the ball and add your own property that stores the position.
class BallNode: SKShapeNode {
var lastPosition: CGPoint?
}
let ball = BallNode()
ball.name = “BALL”
ball.position = CGPoint.zero
self.addChild(ball)
In update....
override func update(_ currentTime: TimeInterval) {
self.enumerateChildNodes(withName: "BALL") { (node:BallNode, nil) in
print(node.position)
if let last= node.lastPosition {
print(last)
// do something with last
}
//Update last position before end of updatE
node.lastPosition = node.position
}
}
Related
I'm working on a project where I'll have a virtual joystick on the screen which moves a character around the board. I found a few good examples and the one I'm using currently is located # https://github.com/Ishawn-Gullapalli/SpritekitJoystick/tree/master/SpritekitJoystick
While the player is moved around just like I want, I'm unable to figure out how by using this method I can change the player animation based on the direction he's going. I'm able to determine direction but my usual methods of invoking a SKAction doesn't animate the player, it just moves him to the new location while pausing the idle animation. I'm moving my player in the update statement like below and am looking for tips on how to change animations appropriately.
I'm including my update statement below. I've also tried to pass in a CGPoint value with the same effect. Thanks in advance for looking.
override func update(_ currentTime: TimeInterval) {
if joystick.joyStickTouched == true {
mainHero.position.x += joystick.moveRight(speed: movementSpeed)
// Example of me trying to animate my player
if joystick.moveRight(speed: movementSpeed) > 0 {
walkRight()
}
mainHero.position.x -= joystick.moveLeft(speed: movementSpeed)
mainHero.position.y += joystick.moveUp(speed: movementSpeed)
mainHero.position.y -= joystick.moveDown(speed: movementSpeed)
joystick.update(currentTime)
}
}
func walkRight() {
mainHero.isPaused = false
let idleAnimation = SKAction(named: "MainWalkRight")!
let rightGroup = SKAction.group([idleAnimation])
mainHero.run(rightGroup, withKey: "Right")
}
My sprite node change position on the screen. And I need to detect when sprite move to up, move to down, move to left, move to right.
Define a variable oldPosition and keep track of the sprite position in the update: method:
var oldPosition: CGPoint?
override func update(_ currentTime: TimeInterval) {
// Called before each frame is rendered
if Int((oldPosition?.x)!) > Int((sprite?.position.x)!) {
// sprite moves to the left
} else if Int((oldPosition?.x)!) < Int((sprite?.position.x)!) {
// sprite moves to the right
}
if Int((oldPosition?.y)!) > Int((sprite?.position.y)!) {
// sprite moves down
} else if Int((oldPosition?.y)!) < Int((sprite?.position.y)!) {
// sprite moves up
}
// keep track
oldPosition = sprite?.position
}
I hope it helps.
You’ve got two options here. As you’ve not posted any code I can’t really advise which is the best:
If you’ve sub-classed SKNode, then override the frame property to add a didSet observer clause:
override var frame : CGRect {
didSet {
// compute the change in the frame’s origin
let delta : CGPoint = CGPoint(x: frame.origin.x - oldValue.origin.x,
y: frame.origin.y - oldValue.origin.y)
// etc
}
}
See SKNode docs at https://developer.apple.com/documentation/spritekit/sknode
If you don’t want to subclass, you can use NSNotificationCenter to add an observer to your node via addObserver:selector:name:object: . See the documentation at:
https://developer.apple.com/library/content/documentation/Cocoa/Conceptual/CoreAnimation_guide/Introduction/Introduction.html
I’d probably go for option 1.
Hope that helps.
I have a rock sprite that it is falling and every time it goes out of the screen I want to reset it back to the top and have it fall again. It should be a continuous cycle. Here's my code:
import SpriteKit
import GameplayKit
class GameScene: SKScene {
func addRock(){
var rock = self.childNode(withName: "rock")
rock?.physicsBody?.affectedByGravity = true
//self.addChild(rock!)
}
override func sceneDidLoad() {
//bRock = self.childNode(withName: "rock")
}
override func touchesBegan(_ touches: Set<UITouch>, with event: UIEvent?) {
//addRock()
var rock = self.childNode(withName: "rock")
rock?.physicsBody?.affectedByGravity = true
/*if (Int((rock?.position.y)!) < Int((self.view?.scene?.view?.bounds.minY)!)){
print("out of screen")
rock?.removeFromParent()
addRock()
}*/
}
override func update(_ currentTime: TimeInterval) {
// Called before each frame is rendered
var rock = self.childNode(withName: "rock")
//rock?.physicsBody?.affectedByGravity = true
if (!intersects(rock!)){
print("out of screen")
rock?.removeFromParent()
addRock()
}
}
}
I have the rock coming on the screen and then falling. Once it leaves the screen, it does not reset and I get an error. I tried placing the reset code in both the touchesBegan and update functions but neither work. If someone could guide me to the correct path, that would be greatly appreciated.
The problem you're having is that you're removing the rock node from the scene but the addRock method doesn't actually add a new rock, it just finds the existing node if there is one and sets a property on its physicsBody. Instead of removing the node, you should just change its position.
Assuming your scene has the default anchor point of (0,0), you can reset the position like this:
override func update(_ currentTime: TimeInterval) {
// Called before each frame is rendered
if let rock = self.childNode(withName: "rock") {
if !intersects(rock!) {
print("out of screen")
rock.position.y = size.height/2 // divided by 2 as discussed in comments
}
}
That will reset the rock's position to the top of the scene and it should resume falling from there.
Three ways:
the same rock is newly located at the right place after leaving the screen, so you just need to set the position of it in (misnamed) addRock (resetRock should be better): rock.position = CGPoint(...). But beware that you also need to reset its velocity, etc, as it was previously moved by physical laws...
create a new rock each time one leaves the screen in addRock: let rock = SKSpriteNode(...)... (and all the initializing code for it. Much simpler as all its physical parameters will be initialized with right values by default.
create a clone of an initial rock. I suppose you have a model of it in your sks file, then don't name it rock but something like (rockModel), and just clone it in addRock with giving it the right name rock. Don't forget to remove the model from the scene at the beginning. This is the usual way to do it.
You could also think about using a series of move actions in a sequence to control the rock's behaviour. Given the move actions are already defined, in your defined sequence, pass in sequence[(falling, hide, backtotop, unhide)] - Repeat Forever.
As long as the rocks don't actually interact with anything and are just for the backdrop/background, hiding and unhiding them is a good way to give the affect they are falling.
I'm new with sprite kit. I have tried simple ball bouncing game with 2 player, another is tracking the ball slowly. But I have discovered a problem. When I move the line to ball (with edge) ball disappearing from the screen. Another times not a problem, ball bouncing. What is the problem?
I have one GameScene, sks and ViewController. My sprite nodes coming from sks. If someone explain this case. It would be better. I have attached what I did below.
My GameScene:
class GameScene: SKScene {
var ball = SKSpriteNode()
var enemy = SKSpriteNode()
var main = SKSpriteNode()
override func didMove(to view: SKView) {
ball = self.childNode(withName: "ball") as! SKSpriteNode
enemy = self.childNode(withName: "enemy") as! SKSpriteNode
main = self.childNode(withName: "main") as! SKSpriteNode
ball.physicsBody?.applyImpulse(CGVector(dx: -20, dy: -20))
ball.physicsBody?.linearDamping = 0
ball.physicsBody?.angularDamping = 0
let border = SKPhysicsBody(edgeLoopFrom: self.frame)
border.friction = 0
border.restitution = 1
self.physicsBody = border
}
override func touchesBegan(_ touches: Set<UITouch>, with event: UIEvent?) {
for touch in touches {
let location = touch.location(in: self)
main.run(SKAction.moveTo(x: location.x, duration: 0.2))
}
}
override func touchesMoved(_ touches: Set<UITouch>, with event: UIEvent?) {
for touch in touches {
let location = touch.location(in: self)
main.run(SKAction.moveTo(x: location.x, duration: 0.2))
}
}
override func update(_ currentTime: TimeInterval) {
// Called before each frame is rendered
enemy.run(SKAction.moveTo(x: ball.position.x, duration: 0.5))
}
View controller:
class GameViewController: UIViewController {
override func viewDidLoad() {
super.viewDidLoad()
if let view = self.view as! SKView? {
// Load the SKScene from 'GameScene.sks'
if let scene = SKScene(fileNamed: "GameScene") {
// Set the scale mode to scale to fit the window
scene.scaleMode = .aspectFill
// Present the scene
view.presentScene(scene)
}
view.ignoresSiblingOrder = true
}
}
override var prefersStatusBarHidden: Bool {
return true
}
Pad settings:
Ball settings:
Some updates
I have tried some messages in update function, then encountered with same case ball goes outside from left side of the device (using iPhone 6S)
2016-12-08 14:27:54.436485 Pong[14261:3102941] fatal error: ball out of left bounds: file
You're pinching the ball against the wall, with the enemy. This means that the force is eventually enough to create enough speed of ball movement/force to overcome the physics system, so it pops through the wall. If you make your enemy stop before it pinces the ball against the wall, you should be fine.
This 'pincing' is occurring because of this line of code:
enemy.run(SKAction.moveTo(x: ball.position.x, duration: 0.5))
This is making the enemy chase the ball, which is a good idea for a ball game, but for the way it's being moved is wrong. Using an Action means the enemy has infinite force applied to it, and is aiming for the middle of the ball.
So when the ball gets to the wall, it's stopped against a physics object with infinite static force, then this enemy comes along and applies infinite force from the other side... and the ball either pops inside the bounds of the enemy, or over the other side of the wall, because it's being crushed by infinite forces.
So you either need to take very good care of how you control the enemy with Actions, or use forces to control the enemy, as these won't be infinite, and the physics system will be able to push back on the enemy.
How easy is it to reproduce the problem? In update(), print the ball's position to see where it is when it has 'disappeared'. (this will produce a lot of output, so be warned).
From what you've posted, it doesn't look like the ball is set to collide with the border, meaning the ball will not react (i.e. bounce off) the border and the border itself is immobile (as it's an edge-based physics body). This, combined with a high ball velocity (from a hard hit) might make it possible that you have hit the ball so hard with the 'main' sprite that it's gone through the border - using preciseCollisionDetection=true might resolve this but give the border a category first and add this to the ball's collisionBitMask.
here is an example of what Steve is saying (in your .update())
if ball.position.x > frame.maxX { fatalError(" ball out of right bounds") }
if ball.position.x < frame.minX { fatalError(" ball out of left bounds") }
if ball.position.y > frame.maxY { fatalError(" ball out of top bounds") }
if ball.position.y < frame.minY { fatalError(" ball out of bottom bounds) }
you could also just spam your debug window:
print(ball.position)
This will help you to find out what is going on--if your ball is flying through the boundary, or if it's getting destroyed somewhere, or some other possible bug.
As a workaround (for now) I would just replace the above "fatalError" with "ball.position = CGPoint(x: 0, y: 0)" or some other position to "reset" the ball in case of it getting lost.
You could even store it's last position in a variable, then restore it to that should the above if-statements trigger.
var lastBallLocation = CGPoint(x: 0, y: 0) // Just to initialize
override func update( prams ) {
if ball.position.x > frame.maxX { ball.position = lastBallLocation }
// .. copy the other three cases
lastBallLocation = ball.position // update only on successful position
Or, you could try making the walls thicker (use a shape node or spritenode and lay them on the outside of the frame such as the walls of a house, and your view on screen is the "room")
each wall also has a physics body for bouncing:
I would like to know how to remove my SKNodes when they are off screen to help my game run more smoothly.
How To Do This On Sprite Kit
Thanks So Much
Here is an easy solution in Swift 4:
class GameScene: SKScene {
let s = SKLabelNode(fontNamed: "Chalkduster")
override func didMove(to view: SKView) {
s.text = "test"
s.fontSize = 50
addChild(s)
let moveRight = SKAction.moveBy(x: 40, y: 0, duration: 0.5)
s.run(SKAction.repeatForever(moveRight))
}
override func update(_ currentTime: TimeInterval) {
// Called before each frame is rendered
if ((s.parent != nil) && !intersects(s)) {
s.removeFromParent()
print("Sprite removed.")
}
}
}
You have a sprite (in this case a SKLabelNode but any sprite node will do) that is moving horizontally and you want to delete this sprite once is out of the frame bounds.
You can use the intersects function to check this and then remove that sprite from its parent. I have also checked that the sprite has a parent before removing it (by checking if s.parent is not nil) as we wish to remove the sprite only once.
https://stackoverflow.com/a/24195006/2494064
Here is a link to an answer that removes nodes that go off the top of the screen. You would just have to replicate this to cover the entire border and set all of the walls to have the same contactBitMask values.
Basically the logic is to remove the SKSpriteNodes when they contact physicsbodies that you have resting just outside the visible screen.