The code below causes the rotateLayer physics body to fall off the screen after a few seconds. Commenting out the circle physics body, however, keeps rotateLayer on screen. Is it not possible to add a physics body to a node, and then rotate the parent node? Conceptually, the goal is to rotate the circle around a fixed point, as described here, but attach a physics body to the circle while also controlling rotation through angular velocity as opposed to zRotation.
let size = CGSize(width: 10, height: 250)
rotateLayer = SKNode()
gameLayer.addChild(rotateLayer)
let circleSize = CGSize(width: 10, height: 10)
let circle = SKSpriteNode(color: SKColor.whiteColor(), size: circleSize)
circle.position = CGPoint(x: 0, y: size.height/2 + circleSize.height/2)
circle.physicsBody = SKPhysicsBody(rectangleOfSize: circleSize)
circle.physicsBody?.affectedByGravity = false
circle.physicsBody?.friction = 0
circle.physicsBody?.linearDamping = 0
circle.physicsBody?.angularDamping = 0
circle.physicsBody?.collisionBitMask = 0
circle.physicsBody?.dynamic = false
rotateLayer.addChild(circle)
rotateLayer.physicsBody = SKPhysicsBody(rectangleOfSize: size)
rotateLayer.physicsBody?.affectedByGravity = false
rotateLayer.physicsBody?.friction = 0
rotateLayer.physicsBody?.linearDamping = 0
rotateLayer.physicsBody?.angularDamping = 0
rotateLayer.physicsBody?.angularVelocity = -3.0
Adding rotateLayer.collisionBitMask = 0 fixed the problem. No clue why.
Related
I'm having a weird Spritekit issue where my moving SKSpriteNode is passing through a fixed SKSpriteNode depending on the position of the fixed SKSpriteNode.
UPDATE: Code works in simulator but not on real device.
Example:
Placing my bin SKSpriteNode at position x: -500, y: 100 works fine and my moving SKSpriteNode collides as expected.
Placing my bin SKSpriteNode at position x: -600, y: 100 DOES NOT work and my moving SKSpriteNode DOES NOT collide with the bin.
Using view.showsPhysics = true shows that there is physics bodies in both cases.
x values between -500 and -508 work as expected. All other values I have tried did not work.
Collisions with my other fixed SKSpriteNodes work as expected.
enum CollisionTypes: UInt32 {
case Plane = 1
case FloorAndRoof = 2
case OtherObject = 4
case FinishPoint = 8
}
Code to create levels
func createLevel(level: Int) {
switch level {
case 1:
createFloor()
createRoof()
createTable(position: CGPoint(x: 750, y: 150))
createCeilingFan(position: CGPoint(x: 750, y: 560))
createCeilingFan(position: CGPoint(x: 2000, y: 560))
createWaterDispenser(position: CGPoint(x: 1500, y: 212))
createBin(position: CGPoint(x: -500, y: 100)) // THIS IS THE PROBLEM LOCATION
createFinishPoint(position: CGPoint(x: -500, y: 100))
break
case 2:
createFloor()
createRoof()
createTable(position: CGPoint(x: 250, y: 150))
createCeilingFan(position: CGPoint(x: 750, y: 560))
createCeilingFan(position: CGPoint(x: 2000, y: 560))
createWaterDispenser(position: CGPoint(x: 1500, y: 212))
createBin(position: CGPoint(x: -600, y: 100))
createFinishPoint(position: CGPoint(x: -300, y: 200))
break
default:
break
}
}
Moving SKSpriteNode
func createPlane() {
plane = SKSpriteNode(imageNamed: "plane1")
plane.name = "plane1"
//plane.position = CGPoint(x: -UIScreen.main.bounds.width + plane.size.width , y: 0)
plane.position = CGPoint(x: 0, y: 300)
plane.zPosition = 1
//plane.physicsBody = SKPhysicsBody(texture: plane.texture!, size: plane.texture!.size())
plane.physicsBody = SKPhysicsBody(texture: planeTexture, size: planeTexture.size())
plane.physicsBody?.allowsRotation = true
plane.physicsBody?.categoryBitMask = CollisionTypes.Plane.rawValue
plane.physicsBody?.collisionBitMask = CollisionTypes.FloorAndRoof.rawValue | CollisionTypes.OtherObject.rawValue // dont collide with finish point
plane.physicsBody?.contactTestBitMask = CollisionTypes.FloorAndRoof.rawValue | CollisionTypes.OtherObject.rawValue | CollisionTypes.FinishPoint.rawValue
plane.physicsBody?.usesPreciseCollisionDetection = true
plane.physicsBody?.isDynamic = true
plane.physicsBody?.friction = 1
plane.physicsBody?.restitution = 0
plane.physicsBody?.mass = 0.1 // customise for different planes
plane.physicsBody?.angularDamping = 1
plane.physicsBody?.linearDamping = 0.2 // customise for different planes
liftFactor = 0.1 // customise for different planes
addChild(plane)
flightMode = 4 // dead, should drop to floor and change to mode 0 when at rest
//print(flightMode)
}
Bin SKSpriteNode that moving Plane should collide with.
func createBin(position: CGPoint) {
binFront = SKSpriteNode(imageNamed: "binFront")
binFront.name = "binFront"
binFront.setScale(0.15)
binFront.position = position
binFront.zPosition = 2 // in front of plane
addChild(binFront)
binBack = SKSpriteNode(imageNamed: "binBack")
binBack.name = "binBack"
binBack.setScale(0.15)
binBack.position = position
binBack.zPosition = 0 // behind plane
addChild(binBack)
binPhysicsBody = SKSpriteNode(imageNamed: "binPhysicsBody")
binPhysicsBody.name = "binPhysicsBody"
binPhysicsBody.physicsBody = SKPhysicsBody(texture: binPhysicsBody.texture!, size: binPhysicsBody.texture!.size())
binPhysicsBody.setScale(0.15)
binPhysicsBody.physicsBody?.allowsRotation = false
binPhysicsBody.physicsBody?.categoryBitMask = CollisionTypes.OtherObject.rawValue
binPhysicsBody.physicsBody?.collisionBitMask = CollisionTypes.Plane.rawValue
binPhysicsBody.physicsBody?.contactTestBitMask = CollisionTypes.Plane.rawValue
binPhysicsBody.physicsBody?.usesPreciseCollisionDetection = false
binPhysicsBody.physicsBody?.isDynamic = false
binPhysicsBody.physicsBody?.friction = 1
binPhysicsBody.physicsBody?.restitution = 0
binPhysicsBody.physicsBody?.mass = 50
binPhysicsBody.position = position
binPhysicsBody.zPosition = 0
addChild(binPhysicsBody)
}
I still don't know the cause of my issue but I got around it by changing the image used to create my physics body. I used a slightly thicker 'wall thickness' on the bin.
I'm trying to create a scenario where there's a radial gravity field. In this scene, there's also an object built by two physics bodies with a different mass.
When I run this code, the radial gravity field is created correctly and the body goes to gravityCenter.
I'm expecting that the body rotates too because the head is heavier than the tail but this doesn't happend.
Why?
class GameScene: SKScene {
let object = SKSpriteNode(imageNamed: "myobj")
let myCategory : UInt32 = 0x1 << 0
override func didMove(to view: SKView) {
self.physicsWorld.gravity = CGVector(dx: 0, dy: 0)
let gravityCenter = SKFieldNode.radialGravityField()
gravityCenter.isEnabled = true
gravityCenter.position = CGPoint(x: size.width, y: size.height * 0.5)
gravityCenter.strength = 0.5
addChild(gravityCenter)
object.position = CGPoint(x: size.width * 0.1, y: size.height * 0.9)
object.scale(to: CGSize(width: 100, height: 25))
let head = SKPhysicsBody(circleOfRadius: object.size.width/5, center: CGPoint(x: object.size.width/2, y: 0))
let tail = SKPhysicsBody(circleOfRadius: object.size.width/50, center: CGPoint(x: -object.size.width/2, y: 0))
head.mass = 500
head.categoryBitMask = myCategory
head.allowsRotation = true
head.isDynamic = true
head.angularDamping = 0
head.affectedByGravity = true
tail.mass = 2
tail.categoryBitMask = myCategory
tail.allowsRotation = true
tail.isDynamic = true
tail.angularDamping = 0
tail.affectedByGravity = true
object.physicsBody = SKPhysicsBody(bodies: [head, tail])
object.physicsBody?.categoryBitMask = myCategory
object.physicsBody?.allowsRotation = true
object.physicsBody?.isDynamic = true
object.physicsBody?.angularDamping = 0
object.physicsBody?.affectedByGravity = true
addChild(object)
}
}
Well, from a physics standpoint SpriteKit is behaving correctly. If you think about it, more mass does mean more gravitational force, but it also means more inertia, which exactly cancels out the increased force. Perhaps introduce a little bit of linearDamping into the tail? That would get the body to rotate by making the head drag the tail a little bit.
I am having a little bit of trouble positioning two SKSpriteNodes correctly in my GameScene. My nodes appear in the scene, but they are zoomed in and take up most of the entire scene. I would to have the output similar to this:
Here is my current code:
let size = CGRect(x: 100, y:98, width:200, hight:271)
bottomRectangle = SKSpriteNode(imageNamed: "bottomRectangle")
bottomRectangle.zPosition = 3
bottomRectangle.size.height = self.size.height
bottomRectangle.size.width = self.size.width
bottomRectangle.position = CGPoint(x: 200, y:271)
bottomRectangle.physicsBody = SKPhysicsBody(edgeLoopFromRect: size)
self.addChild(bottomRectangle)
topRectangle = SKSpriteNode(imageNamed: "topRectangle")
topRectangle.physicsBody = SKPhysicsBody(edgeLoopFromRect: size)
topRectangle.zPosition = 4
topRectangle.size.height = self.size.height
topRectangle.size.width = self.size.width
topRectangle.position = CGPoint(x: 100, y: 98)
self.addChild(topRectangle)
You are using the size of the scene, because of:
self.size.height
You have to use you local variable:
size.height
I would like two regions, as shown in the image below, where the yellow region is to contain sprites. For example I'd like to have balls in the yellow region bouncing and reflecting off the boundaries of the yellow region. How can I programmatically do this without using an sks file?
You create an edge based physics body using the +bodyWithEdgeLoopFromRect:
override func didMoveToView(view: SKView) {
//Setup scene's physics body (setup the walls)
physicsBody = SKPhysicsBody(edgeLoopFromRect: frame)
let yellowSprite = SKSpriteNode(color: .yellowColor(), size: CGSize(width: 300, height: 300))
yellowSprite.position = CGPoint(x: frame.midX, y: frame.midY)
//Create the rectangle which will represent physics body.
let rect = CGRect(origin: CGPoint(x: -yellowSprite.size.width/2, y: -yellowSprite.size.height/2), size: yellowSprite.size)
yellowSprite.physicsBody = SKPhysicsBody(edgeLoopFromRect: rect)
addChild(yellowSprite)
//Add Red ball "inside" the yellow sprite
let red = SKShapeNode(circleOfRadius: 20)
red.fillColor = .redColor()
red.strokeColor = .clearColor()
red.position = yellowSprite.position
red.physicsBody = SKPhysicsBody(circleOfRadius: 20)
red.physicsBody?.restitution = 1
red.physicsBody?.friction = 0
red.physicsBody?.affectedByGravity = false
addChild(red)
red.physicsBody?.applyImpulse(CGVector(dx: 20, dy: 15))
}
About rect parameter:
The rectangle that defines the edges. The rectangle is specified
relative to the owning node’s origin.
Hope this helps!
Is it possible to position a physics body on a sprite? I only want a certain part of my sprite node to have collision detection, not the whole image.
Heres my physics body
physicsBody = SKPhysicsBody(rectangleOfSize: CGSize(width: CGFloat(54.0), height: CGFloat(100.0)))
But i want to position the physics body at the top of the node, where it usually gets placed in the middle of the node.
You can try creating a smaller SKSpriteNode of the same size as the SKPhysicsBody and adding the larger SKSpriteNode as a child to the smaller one. Changing the position of the larger one as you want. For example
override func didMoveToView(view: SKView) {
let smallerSprite = SKSpriteNode(color: UIColor.redColor(), size: CGSizeMake(30, 30))
smallerSprite.physicsBody = SKPhysicsBody(rectangleOfSize: smallerSprite.size)
smallerSprite.position = CGPointMake(100, 400)
self.addChild(smallerSprite)
let largerSprite = SKSpriteNode(color: UIColor(white: 0.5, alpha: 0.5), size: CGSizeMake(100, 100))
largerSprite.position = CGPointMake(-10, -10)
smallerSprite.addChild(largerSprite)
self.physicsBody = SKPhysicsBody(edgeLoopFromRect: self.frame)
}
As an addition to rakesh's answer...A different approach to get the same result would be to use
+ bodyWithRectangleOfSize:center: method. Like this:
override func didMoveToView(view: SKView) {
let sprite = SKSpriteNode(color: SKColor.whiteColor(), size: CGSize(width: 100.0, height: 100.0))
//I assume that you have initialized view and scene properly. If so, this will position a sprite in the middle of the screen.
sprite.position = CGPoint(x: CGRectGetMidX(frame), y: CGRectGetMidY(frame))
var physicsBodySize:CGSize = CGSize(width: sprite.size.width, height: 30.0) //Create a size here. You can play with height parameter.
sprite.physicsBody =
SKPhysicsBody(rectangleOfSize: physicsBodySize, center: CGPoint(x: 0.0, y: sprite.size.height / 2.0 - physicsBodySize.height / 2.0))
//Not needed, just set to restrict that sprite can't off screen
sprite.physicsBody?.affectedByGravity = false
self .addChild(sprite)
}
The result:
If you try to change the height of physics body to 10.0, you will get something like this: