I am creating a game and I set up the background already. Now when I put in the code to add the character to the scene it does not appear. This is the code I used to try and get the character to appear on the screen. Apparently my character shows up behind the background. Is there another way to get the character to show in front of the background?
func createPlayer() -> SKNode {
let playerNode = SKNode()
playerNode.position = CGPoint(x: self.size.width / 2, y: 80.0)
let sprite = SKSpriteNode(imageNamed: "Pig")
playerNode.addChild(sprite) return playerNode }
In order to make the character appear in front of the background image you need to use zposition:
//You need to choose a high zposition number to make sure it shows up in front.
playerNode.zPosition = 1
// you should set the background images z position using the same method to something below 1
I would also recommend using this to add your character to the scene:
self.addChild(playerNode)
Related
I am making a game in Swift using spritekit and I want 2 objects on screen, one that I move with the touchesMoved function (player) and the other to stay still in its position in the screen (cell).
I wanted to make the objects physicsbody's so that I could work out collisions between them, but now whenever the scene loads the objects fall straight away. And the object moved through touch falls as soon as the user stops touching the screen.
Here's all of the code relating to the object that should stay stationary in the scene and I am unsure what makes it fall.
//Defining the cell
let cell = SKSpriteNode(imageNamed: "cell.png")
override func didMove(to view: SKView){
self.physicsWorld.contactDelegate = self
cell.physicsBody?.categoryBitMask = cellCategory
cell.physicsBody?.contactTestBitMask = playerCategory
cell.physicsBody?.isDynamic = true
cell.physicsBody = SKPhysicsBody(rectangleOf: cell.frame.size)
//Adding the cell to the scene
cell.position = CGPoint(x:size.width * 0.9, y:size.height * 0.9)
cell.size = CGSize(width: 50, height: 50)
addChild(cell)
Any help in what makes the object fall and how I can stop it from happening would be greatly appreciated.
Gravity is by default on. You can either turn it off entirely by setting the gravity property of the scene's physicsWorld:
// somewhere in the scene's initialization, or in didMove if you like
physicsWorld.gravity = CGVector(dx: 0.0, dy: 0.0)
See https://developer.apple.com/documentation/spritekit/skphysicsworld for info on that.
Or you can turn off whether individual objects are affected by gravity. E.g.,
let body = SKPhysicsBody(circleOfRadius: 10.0)
body.affectedByGravity = false
See https://developer.apple.com/documentation/spritekit/skphysicsbody, and in particular, https://developer.apple.com/documentation/spritekit/skphysicsbody/1519774-affectedbygravity
You have a different problem in that you're setting the properties of your cell's physics body before you're creating it. cell.physicsBody?... = will not assign anything until cell.physicsBody exists. So those assignments must be moved after you create cell.physicsBody = SKPhysicsBody(rectangleOf: ...)
I have a moving camera in my scene, which always follows my player. But I also have some other content(On screen controls) which I want to stay in a single place on the screen, but when the camera moves, The controls are moving away to. How would I go about doing this. I have searched a lot, and found the SKConstraint, but I couldn't find any tutorials to use it in swift 3.
Should I be using the SKConstraint? If yes, how can I use it, if no, how do I keep the controls at a certain position on the screen at all times.
I also know that I could change the position of the controls in the update method, but I do not want to do that as there are many on screen controls, and I try to refrain from writing code in the update method as much as possible.
Any help would be appreciated, thanks!
You can use an SKConstraint to cause a camera to follow a character.
First, create a camera node and a hero and add them to the scene
let cameraNode = SKCameraNode()
let hero = SKSpriteNode(imageNamed: "Spaceship")
addChild(hero)
camera = cameraNode
addChild(cameraNode)
Next, create a constraint and assign it to the camera node's constraints property
let range = SKRange(constantValue:0)
let constraint = SKConstraint.distance(range, to: hero)
cameraNode.constraints = [constraint]
Lastly, if you have controls or labels that need to be at fixed locations relative to the camera, you can add them to the camera node
let label = SKLabelNode(text: "Score: 123")
// Position the label relative to the camera node
label.position = CGPoint(x: 100, y: 100)
cameraNode.addChild(label)
I'm teaching myself how to do SpriteKit programming by coding up a simple game that requires that I lay out a square "game field" on the left side of a landscape-oriented scene. I'm just using the stock 1024x768 view you get when creating a new SpriteKit "Game" project in XCode - nothing fancy. When I set up the game field in didMoveToView(), however, I'm finding the coordinate system to be a little weird. First of all, I expected I would have to place the board at (0, 0) for it to appear in the lower-left. Not so -- it turns out the game board has to be bumped up about 96 pixels in the y direction to work. So I end up with this weird code:
let gameFieldOrigin = CGPoint(x:0, y:96) // ???
let gameFieldSize = CGSize(width:560, height: 560)
let gameField = CGRect(origin: gameFieldOrigin, size: gameFieldSize)
gameBorder = SKShapeNode(rect: gameField)
gameBorder.strokeColor = UIColor.redColor()
gameBorder.lineWidth = 0.1
self.addChild(gameBorder) // "self" is the SKScene subclass GameScene
Furthermore, when I add a child to it (a ball that bounces inside the field), I assumed I would just use relative coordinates to place it in the center. However, I ended up having to use "absolute" coordinate and I had to offset the y-coordinate by 96 again.
Another thing I noticed is when I called touch.locationInNode(gameBorder), the coordinates were again not relative to the border, and start at (0, 96) at the bottom of the border instead of (0, 0) as I would have guessed.
So what am I missing here? Am I misunderstanding something fundamental about how coordinates work?
[PS: I wanted to add the tag "SpriteKit" to this question, but I don't have enough rep. :/]
You want to reference the whole screen as a coordinate system, but you're actually setting all the things on a scene loading from GameScene.sks. The right way to do is modify one line in your GameViewController.swift in order to set your scene size same as the screen size. Initialize scene size like this instead of unarchiving from .sks file:
let scene = GameScene(size: view.bounds.size)
Don't forget to remove the if-statement as well because we don't need it any more. In this way, the (0, 0) is at the lower-left corner.
To put something, e.g. aNode, in the center of the scene, you can set its position like:
aNode.position = CGPoint(x:CGRectGetMidX(self.frame), y:CGRectGetMidY(self.frame));
I'm looking for the proper SpriteKit way to handle something of a scrollable world. Consider the following image:
In this contrived example, the world boundary is the dashed line and the blue dot can move anywhere within these boundaries. However, at any given point, a portion of this world can exist off-screen as indicated by the image. I would like to know how I can move the blue dot anywhere around the "world" while keeping the camera stationary on the blue dot.
This is Adventure, a sprite kit game by apple to demonstrate the point I made below. Read through the docs, they explain everything
Theres a good answer to this that I can't find at the moment. The basic idea is this:
Add a 'world' node to your scene. You can give it a width/height that is larger than the screen size.
When you 'move' the character around (or blue dot), you actually move your world node instead, but in the opposite direction, and that gives the impression that you're moving.
This way the screen is always centered on the blue dot, yet the world around you moves
below is an example from when I was experimenting a while ago:
override func didMoveToView(view: SKView) {
self.anchorPoint = CGPointMake(0.5, 0.5)
//self.size = CGSizeMake(600, 600)
// Add world
world = SKShapeNode(rectOfSize: CGSize(width: 500, height: 500))
world.fillColor = SKColor.whiteColor()
world.position = CGPoint(x: size.width * 0.5, y: size.height * 0.5)
world.physicsBody?.usesPreciseCollisionDetection = true
self.addChild(world)
}
override func update(currentTime: CFTimeInterval) {
world.position.x = -player.position.x
world.position.y = -player.position.y
}
override func didSimulatePhysics() {
self.centerOnNode(self.camera)
}
func centerOnNode(node: SKNode) {
if let parent = node.parent {
let nodePositionInScene: CGPoint = node.scene!.convertPoint(node.position, fromNode: parent)
parent.position = CGPoint(
x: parent.position.x - nodePositionInScene.x,
y: parent.position.y - nodePositionInScene.y)
}}
If you create a "camera" node which you add to your "world" node, a couple of simple functions (above) allow you to "follow" this camera node as it travels through the world, though actually you are moving the world around similar to Abdul Ahmad's answer.
This method allows you to use SpriteKit functionality on the camera. You can apply physics to it, run actions on it, put constraints on it, allowing effects like:
camera shaking (an action),
collision (a physics body, or matching the position of another node with a physics body),
a lagging follow (place a constraint on the camera that keeps it a certain distance from a character, for example)
The constraint especially adds a nice touch to a moving world as it allows the "main character" to move around freely somewhat while only moving the world when close to the edges of the screen.
I have a function in SpriteKit that spawns a sprite (which is a square) at the top of the screen, and then gravity pulls the sprite to the bottom of the screen. I'm trying to get the sprite to rotate smoothly for an indefinite amount of time until it is removed when it reaches the bottom of the screen. The following code is in the class for the sprite:
func rotate() {
var action = SKAction.rotateByAngle(CGFloat(M_PI_2), duration: NSTimeInterval(1.5))
var repeatAction = SKAction.repeatActionForever(action)
self.runAction(repeatAction)
}
The problem that I am having is that, as the sprite turns, the sprite travels in the direction of the bottom of itself, not towards the bottom of the screen (the direction gravity is supposed to be). To further clarify, the object rotates, but as it rotates to 90 degrees, it travels sideways instead of downwards. This doesn't make sense to me. This is the code I'm using to add gravity in the didMoveToView() function:
self.physicsWorld.gravity = CGVectorMake(0.0, -1.8)
and this is the code used to spawn the sprite (the rs.rotate() calls the rotate method that is listed above):
func spawnRedSquares() {
if !self.gameOver {
let rs = RedSquare()
var rsSpawnRange = randomNumberBetween(self.leftSideBar.position.x + rs.sprite.size.width / 2, secondNum: self.rightSideBar.position.x - rs.sprite.size.width / 2)
rs.position = CGPointMake(rsSpawnRange, CGRectGetMaxY(self.frame) + rs.sprite.size.height * 2)
rs.zPosition = 3
self.addChild(rs)
self.rsArray.append(rs)
rs.rotate()
let spawn = SKAction.runBlock(self.spawnRedSquares)
let delay = SKAction.waitForDuration(NSTimeInterval(timeBetweenRedSquares))
let spawnThenDelay = SKAction.sequence([delay, spawn])
self.runAction(spawnThenDelay)
}
}
How can I get the object to rotate, but still fall down as if it were affected by normal gravity?
It looks like you are adding the rotation action to 'self' which I would assume is your scene as opposed to your sprite. This is causing the entire scene to rotate, and therefore its gravity is rotating as well.
Add the rotating action to your sprite and that should solve the issue.
Example: assuming your square sprite is called squareSprite:
let action = SKAction.rotateByAngle(CGFloat(M_PI_2), duration: NSTimeInterval(2))
let repeatAction = SKAction.repeatActionForever(action)
squareSprite.runAction(repeatAction) //Add the repeatAction to your square sprite