Is there a way to rotate an SKShapeNode, specifically a rectangle, around some arbitrary point?
I declared my SKShapeNode at the beginning of my gameScene class
var bladeTouch = SKShapeNode()
and set its path to form a rectangle
bladeTouch.path = CGPathCreateWithRect(CGRectMake(0, 0, 60, 198), nil)
However "bladeTouch" only manages to rotate around its bottom left corner, while my intention is to have it rotate around a point on the middle of its bottom edge. How would I go about translating its path so that this is possible?
This would be simplest:
bladeTouch.path = CGPathCreateWithRect(CGRectMake(-30, 0, 60, 198), nil)
Related
I have a SpriteKit game in which balls bounce around, interacting with other objects.
One of those other objects is a spinner that should rotate around its center, but NOT change its x/y position. It should be stationary except for the rotation.
According to Apple's documentation, node.physicsBody.pinned = true should do exactly what I want, making it so that:
"the node’s position is fixed relative to its parent. The node’s position cannot be changed by actions or physics forces. The node can freely rotate around its position in response to collisions or other forces."
However, that's not what's happening. What's happening is that the spinner's y-axis position changes when a ball hits it squarely -- briefly moving down and then popping back into the correct position.
My code for the spinner (please assume all variables are defined):
for i in 0..<spinners.count {
let spinnerNode = SKSpriteNode(texture: texture)
spinnerNode.position = CGPoint(x: spinners[i].minX, y: spinners[i].minY)
spinnerNode.size = CGSize(width: spinners[i].width, height: spinners[i].height)
spinnerNode.physicsBody = SKPhysicsBody(texture: spinnerNode.texture!, size: CGSize(width: spinners[i].width, height: spinners[i].height))
spinnerNode.physicsBody?.isDynamic = true
spinnerNode.physicsBody?.affectedByGravity = false
spinnerNode.physicsBody?.pinned = true
addChild(spinnerNode)
}
Why on earth is my spinner node moving vertically when a ball collides with it? Why isn't .pinned working as advertised?
Thank you for your help!
I solved the problem by setting the spinner node's mass to a value slightly greater than that of the ball nodes.
node.physicsBody?.mass = 6.0
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 have added a SKNode to my SKView by using this code:
tile.fillColor = SKColor.blueColor()
tile.position = CGPoint(x: 64, y: 64)
self.addChild(tile)
However, after fiddling with window sizes in the MainMenu.xib file, the position of tile becomes inaccurate even when the SKView lines up with the window itself:
How do I fix this?
Modifying the tile's anchor point might make it easier to place. I'm not 100% clear on where precisely you want to place that tile, but if you were trying to get that tile lined up on the bottom edge, and 64 from the left edge of the parent, you could simplify things by moving the anchor point of the tile to its bottom left before placing it. By default, as rakeshbs points out, the anchor point is at the center of the tile.
tile.fillColor = SKColor.blueColor()
tile.anchorPoint = CGPointMake(0, 0)
tile.position = CGPoint(x: 64, y: 0)
self.addChild(tile)
Maybe you're already aware of the ability to modify the anchor point on a SKSpriteNode, if so please disregard; perhaps I'm not fully understanding your issue.
I'm working in a side-scolling game and I need to know what nodes are in an area to implement something like "line of sight". Right now I'm trying using enumerateBodyiesInRect() however it's detecting bodies that are 20px or more from the evaluated rect and I cannot figure out why it's so imprecise.
This is what I'm trying now:
import SpriteKit
import CoreMotion
class GameScene: SKScene, SKPhysicsContactDelegate
{
var player = SKShapeNode()
var world = SKShapeNode()
var rShape = SKShapeNode()
override func didMoveToView(view: SKView) {
self.physicsWorld.contactDelegate = self
self.scaleMode = SKSceneScaleMode.AspectFit
self.size = view.bounds.size
// Add world
world = SKShapeNode(rectOfSize: view.bounds.size)
world.physicsBody = SKPhysicsBody(edgeLoopFromPath: world.path)
world.position = CGPointMake(self.frame.size.width/2, self.frame.size.height/2) // Move camera
self.addChild(world)
// Add player
player = SKShapeNode(rectOfSize: CGSize(width: 25, height: 25))
player.physicsBody = SKPhysicsBody(rectangleOfSize: player.frame.size)
player.physicsBody.dynamic = false
player.strokeColor = SKColor.blueColor()
player.fillColor = SKColor.blueColor()
player.position = CGPointMake(90, -50)
world.addChild(player)
}
override func update(currentTime: CFTimeInterval) {
// Define rect position and size (area that will be evaluated for bodies)
var r : CGRect = CGRect(x: 200, y: 200, width: 25, height: 25)
// Show rect for debug
rShape.removeFromParent()
rShape = SKShapeNode(rect: r)
rShape.strokeColor = SKColor.redColor()
self.addChild(rShape)
// Evaluate rect
rShape.fillColor = SKColor.clearColor()
self.physicsWorld.enumerateBodiesInRect(r) {
(body: SKPhysicsBody!, stop: UnsafePointer<ObjCBool>) in
self.rShape.fillColor = SKColor.redColor() // Paint the area blue if it detects a node
}
}
}
This code should show the evaluated rect and ray on the screen (for debugging purposes) and paint them red if they contact the player node. However you can see in the screenshot how it turns red when the player is 25px or more away from it, it's like if the drawing is a little bit off, or smaller than the actual area being evaluated. You can copy paste it to a project to duplicate the problem.
Could this be because this is just beta or am I doing something wrong?
You are creating a physical world where there is a specific rectangle that has 'special properties' - this is the rectangle that you use in enumerateBodiesInRect(). Why not create an invisible, inert physical body with the required rectangular dimension and then use SKPhysicsBody to check for collisions and/or contacts? You could then use allContactedBodies() or some delegate callbacks to learn what other bodies are inside your special rectangle.
Think of it like a 'tractor beam' or a 'warp rectangle'.
I believe you want SKPhysicsWorld's enumerateBodyiesInRect() instance method, which will iterate over all nodes in a given rectangle. If you're looking to get at the physics world through your scene, usage could look like this:
self.physicsWorld.enumerateBodiesInRect(CGRect(x: 0, y: 0, width: 50, height: 50)) {(body: SKPhysicsBody!, stop: UnsafePointer<ObjCBool>) in
// enumerates all nodes in given frame
}
I've experimented quite a bit with enumerateBodiesInRect now, and I've found it to be incredibly inaccurate. It seems to not have any of the claimed functionality, and instead produces random results. I honestly cannot even determine any pattern from its products.
enumerateBodiesAlongRay seems better, but still very buggy. The problem with that function seems to be the conversion between Screen and PhysicsWorld coordinates. I would avoid that one, as well.
I think your solution should simply be to use the existing contact detection system. All of your desired functionality can be written in the didBeginContact() and didEndContact() functions. This has the added benefit of allowing you to specify distinct functionality for both entering and leaving the area. You can also add particle effects, animations, and similar, as well as intentionally ignoring specific types of nodes.
The only thing to ensure success with this method is to clarify that the contact area has a unique category, that the contactTestBitMask contains all desired nodes and the collisionBitMask is set to 0.
The enumerateBodiesInRect method of SKPhysicsWorld expects the rect parameter to be in scene coordinates. This is important. If you have a scene hierarchy of nodes, you need to convert the rect you calculate from a reference node to the scene coordinates.
I faced a lot of issues with this method returning bodies that were off by values like 30px to the left etc. and finally realized the issue was because of the rect parameter not defined in scene coordinate space.
In my case, I had a worldNode inside my scene, and all objects were created in the worldNode. My camera was moving the worldNode about, and applying scaling to it for zooming out and in.
In order to use enumerateBodiesInRect correctly, I had to do something as follows:
// get your world rect based on game logic
let worldRect = getWorldRect()
// calculate the scene rect
let sceneRectOrigin = scene.convertPoint(worldRect.origin, fromNode:scene.worldNode)
let worldScale = scene.worldNode.xScale // assert this is not 0
// now to get the scene rect relative to the world rect, in scene coordinates
let sceneRect = CGRectMake( sceneRectOrigin.x, sceneRectOrigin.y, worldRect.width / worldScale, worldRect.height / worldScale)
world.physicsWorld.enumerateBodiesInRect(sceneRect) {
// your code here
}
Hope this helps.
I am not sure if this is a good practice. Correct me if not. But I am using
let shapeNode = SKShapeNode()
shapeNode.intersects(playerNode)
I checked selected nodes with simple loop if they intersect the player. Additionally I created SKShapeNodes which are drawn in front of nodes representing view sight of other actors in the game. They are moved along those actors.
There is only nodesAtPoint: method.
To achieve what you want you'd better to store all enemies in an array and have an int variable, something like nextEnemyIndex. This approach lets you to easily return the next enemy node, it's much more efficient than trying to find a node on the scene.
yes problem may occur because of your player's image, for example try to use 10px smaller body size:
player.physicsBody = SKPhysicsBody(rectangleOfSize: CGRectMake(self.frame.origin.x, self.frame.origin.y, self.size.width-10, self.size.height-10)));