I'm trying to create an ellipse in the center of my scene:
let center = (CGRectGetMidX(view.scene.frame), CGRectGetMidY(view.scene.frame))
let size = (view.scene.frame.size.width * 0.3, view.scene.frame.size.height * 0.3)
let ellipse = SKShapeNode (ellipseInRect: CGRectMake(center.0, center.1, size.0, size.1))
ellipse.strokeColor = UIColor.blackColor()
ellipse.position = CGPointMake(center)
self.addChild(ellipse)
This was added to didMoveToView, and the node count on the view shows 1, but I do not see the path. How do I add an ellipse to my scene using the SKShapeNode ellipseInRect API?
The problem lies in ellipse.position = CGPointMake(center). For some reason, this changes the position of the ellipse relative to itself rather than relative to the view - so if you did ellipse.position = CGPoint(x: 100, y: 100) then it would set the position to 100 up and 100 to the right of the ellipse itself as opposed to 100,100 on the scene. If you comment out this line, then you should be able to see you ellipse on the screen - I certainly could when it tried it. Hope that helps you position it to where you want.
Related
I'm trying to calculate SpriteKit overlay content position (not just overlaying visual content) over specific geometry points ARFaceGeometry/ARFaceAnchor.
I'm using SCNSceneRenderer.projectPoint from the calculated world coordinate, but the result is y inverted and not aligned to the camera image:
let vertex4 = vector_float4(0, 0, 0, 1)
let modelMatrix = faceAnchor.transform
let world_vertex4 = simd_mul(modelMatrix, vertex4)
let pt3 = SCNVector3(x: Float(world_vertex4.x),
y: Float(world_vertex4.y),
z: Float(world_vertex4.z))
let sprite_pt = renderer.projectPoint(pt3)
// To visualize sprite_pt
let dot = SKSpriteNode(imageNamed: "dot")
dot.size = CGSize(width: 7, height: 7)
dot.position = CGPoint(x: CGFloat(sprite_pt.x),
y: CGFloat(sprite_pt.y))
overlayScene.addChild(dot)
In my experience, the screen coordinates given by ARKit's projectPoint function are directly usable when drawing to, for example, a CALayer. This means they follow iOS coordinates as described here, where the origin is in the upper left and y is inverted.
SpriteKit has its own coordinate system:
The unit coordinate system places the origin at the bottom left corner of the frame and (1,1) at the top right corner of the frame. A sprite’s anchor point defaults to (0.5,0.5), which corresponds to the center of the frame.
Finally, SKNodes are placed in an SKScene which has its origin on the bottom left. You should ensure that your SKScene is the same size as your actual view, or else the origin may not be at the bottom left of the view and thus your positioning of the node from view coordinates my be incorrect. The answer to this question may help, in particular checking the AspectFit or AspectFill of your view to ensure your scene is being scaled down.
The Scene's origin is in the bottom left and depending on your scene size and scaling it may be off screen. This is where 0,0 is. So every child you add will start there and work its way right and up based on position. A SKSpriteNode has its origin in the center.
So the two basic steps to convert from view coordinates and SpriteKit coordinates would be 1) inverting the y-axis so your origin is in the bottom left, and 2) ensuring that your SKScene frame matches your view frame.
I can test this out more fully in a bit and edit if there are any issues
Found the transformation that works using camera.projectPoint instead of the renderer.projectPoint.
To scale the points correctly on the spritekit: set scaleMode=.aspectFill
I updated https://github.com/AnsonT/ARFaceSpriteKitMapping to demo this.
guard let faceAnchor = anchor as? ARFaceAnchor,
let camera = sceneView.session.currentFrame?.camera,
let sie = overlayScene?.size
else { return }
let modelMatrix = faceAnchor.transform
let vertices = faceAnchor.geometry.vertices
for vertex in vertices {
let vertex4 = vector_float4(vertex.x, vertex.y, vertex.z, 1)
let world_vertex4 = simd_mul(modelMatrix, vertex4)
let world_vector3 = simd_float3(x: world_vertex4.x, y: world_vertex4.y, z: world_vertex4.z)
let pt = camera.projectPoint(world_vector3, orientation: .portrait, viewportSize: size)
let dot = SKSpriteNode(imageNamed: "dot")
dot.size = CGSize(width: 7, height: 7)
dot.position = CGPoint(x: CGFloat(pt.x), y: size.height - CGFloat(pt.y))
overlayScene?.addChild(dot)
}
Completely new to SpriteKit. Currently I have a UIView, and I want to add a sprite node to it (like a small UIImageView, but I want animation for it so using SpriteKit). Therefore I didn't initialize my project to be a game project, as found in almost all of tutorials for SpriteKit. I've found a note here: link and what I have now is sth like:
func initializeImage() {
let imageView = SKView()
imageView.frame = CGRect(x: self.frame.width / 2 - Constants.imageWidth / 2, y: self.frame.height - Constants.imageHeight, width: Constants.imageWidth, height: Constants.imageHeight)
// so place it somewhere in the bottom middle of the whole frame
let sheet = SpriteSheet(texture: ...)
let sprite = SKSpriteNode(texture: sheet.itemFor(column: 0, row: 0))
sprite.position = imageView.center //basically the same position as the imageView.frame's x and y value
let scene = SKScene(size: imageView.frame.size)
scene.backgroundColor = SKColor.clear
scene.addChild(sprite)
imageView.presentScene(scene)
self.frame.addSubview(imageView)
}
The SpriteSheet is similar to this: sprite sheet; it's essentially cutting an image atlas and divide it into smaller images. I tracked the process and this step is indeed giving the smaller image (the var 'sprite'). But if running I only have a black square now (should be the size as defined by Constants). If I set scene.backgroundColor to be white then it's white. May I know how I should proceed from here, as how should I make the sprite showing up?
All of your code looks good except for this:
sprite.position = imageView.center // basically the same position as the imageView.frame's x and y value
That is basically not the position you think it is. The coordinate system in SpriteKit is a) relative to the (SK)scene, not to whatever view the SKView is contained in, and b) flipped vertically relative to the UIKit coordinate system. If you want a sprite centered in the scene, you probably want to set its position based on the scene's size:
sprite.position = CGPoint(x: scene.size.width / 2, y: scene.size.height / 2)
By the way, the external SpriteSheet code might not be needed (and you're more likely to benefit from Apple's optimizations) if you slice up your sprite sheet and put it in an Xcode asset catalog.
Im trying to pin the game pad controller to the bottom left on my camera node but when i add the node as a child of my camera it doesnt show up?
let gameCamera = SKCameraNode()
var joypadBackground : SKSpriteNode = SKSpriteNode(imageNamed: "a")
override func didMove(to view: SKView) {
//Set game camera
self.camera = gameCamera
joypadBackground.position = convert(CGPoint(x: 0, y: 0), to: gameCamera)
joypadBackground.size = CGSize(width: 50, height: 50)
joypadBackground.zPosition = 1000
gameCamera.addChild(joypadBackground)
}
I had a hard time with this same problem the first time I was working with SKCameraNode and creating a heads up display.
Basically you have to remember that there are two parts to the camera. Running its functionality and rendering its children. By setting the scene's camera to gameCamera you've setup the functionality, but your camera isn't in the node tree for rendering. So, if you ever have a camera that needs to render its children don't forget to add it to the scene as a child, then the camera's children will be displayed.
self.camera = gameCamera
self.addChild(gameCamera)
Hope that helps someone avoid a very common error with a very simple solution.
You don't need
convert(CGPoint(x: 0, y: 0), to: gameCamera)
You can just set the CGPoint position to (0,0) and it should be at that point relative to the camera's space.
Not sure if this helps, at all, but what I do is (generally) position a child node AFTER I've added it to its parent. This is mainly a mental reminder, to me, that the child's position is within the coordinate space of the parent. So I'd do something like this:
gameCamera.addChild(joypadBackground)
joypadBackground.position = CGPoint(x: 0, y: 0)
If you're using a mid screen origin in your SKScene, this should be in the middle of the screen.
Bottom left will be a negative x and negative y value, size of which is relative to your frame size.
What do I need to code in order to have an image (that is already in the assets.xcassets) displayed as the background of the GameScene.swift?
First of all you could call you scene with the scaleMode .resizeFill that modify the SKScene's actual size to exactly match the SKView :
scene.scaleMode = .resizeFill
.resizeFill – The scene is not scaled. It is simply resized so that its fits the view. Because the scene is not scaled, the images will all remain at their original size and aspect ratio. The content will all remain relative to the scene origin (lower left).
By default, a scene’s origin is placed in the lower-left corner of the view. So, a scene is initialized with a height of 1024 and a width of 768, has the origin (0,0) in the lower-left corner, and the (1024,768) coordinate in the upper-right corner. The frame property holds (0,0)-(1024,768).The default value for the anchor point is CGPointZero (so you don't need to change it), which places it at the lower-left corner.
Finally, you can use the code below to add your background image (called of example bg.jpg):
// Set background
let txt = SKTexture(imageNamed: "bg.jpg")
let backgroundNode = SKSpriteNode(texture: txt, size:size)
self.addChild(backgroundNode)
backgroundNode.position = CGPoint(x: self.frame.midX, y: self.frame.midY)
Although this might not be the best way, but it's what I always do, and it works.
Assuming that you have an image that is exactly the same aize as your scene, you can do this:
// please declare bg as a class level variable
bg = SKSpriteNode(imageNamed: "name of your texture")
// the below two lines of code is my preference only. I want the
// background's anchor point to be the bottom left of the screen
// because IMO it's easier to add other sprites as children of the background.
bg.anchorPoint = CGPoint.zero
bg.position = CGPoint(x: self.frame.width / -2, y: self.frame.height / -2)
self.addChild(bg)
Alernatively, just do this in an sks file. It's much easier.
After that, add all your game sprites as children of bg instead of self because it is easier to manage.
I created a SKShapeNode called smallScreen and an SKLabelNode with the name screenLabel.
I later attempted to display screenLabel in smallScreen. When I ran the code however, it didn't work. I tried adding screenLabel as a child to self, and that seemed to allow the text to display. Whenever I added screenLabel as a child node to smallScreen, it wouldn't display. Please help, much thanks.
self.smallScreen = (self.childNodeWithName("screen") as? SKShapeNode)!
self.smallScreen.position = CGPoint(x: self.frame.size.width/2, y: self.frame.size.height * 2/3)
screenLabel.text = "Screen"
screenLabel.fontSize = 30
screenLabel.fontColor = UIColor.redColor()
screenLabel.position = CGPoint(x: self.frame.size.width/2, y: self.frame.size.height * 2/3)
screenLabel.hidden = false
self.smallScreen.addChild(screenLabel)
In Sprite-kit by default, a scene’s origin is placed in the lower-left corner of the view. Its default value is CGPointZero and you can’t change it. (source).
A sprite’s (SKSpriteNode) anchor point defaults to (0.5,0.5), which corresponds to the center of the frame (source).
SKShapeNode does not have an anchorPoint.
LearnCocos2D answered on this issue:
When you use an image you may need to align it on its node's position.
There's no other way to do so but through anchorPoint because the
image itself can't be modified (not easily anyway).
When you create a shape you have full control over the alignment of
the shape through CGPath. You can simply translate the path to change
the shape's alignment relative to the node's position.
This is my interpretation, not fact.
So , what happened to your code?
I don't know how you have initialized your shape, I make just an example:
/* Create a Shape Node representing a rect centered at the Node's origin. */
#available(iOS 8.0, *)
public convenience init(rectOfSize size: CGSize)
So we create the shape like this:
self.smallScreen = SKShapeNode.init(rectOfSize: CGSizeMake(200,200))
First, you place your SKShapeNode to the X center of the screen for the X coordinates, and Y = self.frame.size.height * 2/3. In fact, your smallScreen is visible.
Speaking about your label, you have add it to the smallScreen, so screenLabel must respect the alignment of his parent.
In fact you can see your label simply by making this change:
From:
screenLabel.position = CGPoint(x: self.frame.size.width/2, y: self.frame.size.height * 2/3)
To:
screenLabel.position = CGPointZero
and your label is positioned to the center of the smallScreen according to the alignment of his parent.