I am currently running the following code on a sprite node.
// the circle path's diameter
let circleDiameter = CGFloat(150)
// center our path based on our sprites initial position
let pathCenterPoint = CGPoint(
x: player.position.x - circleDiameter/2,
y: player.position.y - circleDiameter/2
)
// create the path our sprite will travel along
let circlePath = CGPath(ellipseIn: CGRect(origin: pathCenterPoint, size: CGSize(width: circleDiameter, height: circleDiameter)), transform: nil)
// create a followPath action for our sprite
let followCirclePath = SKAction.follow(circlePath, asOffset: false, orientToPath: true, duration: 4)
// make our sprite run this action forever
player.run(SKAction.repeatForever(followCirclePath))
self.addChild(player)
Currently the code works fine, however the player rotates as it moves in a circle path. Is there anyway I can stop the player sprite from rotating as well, as it moves in a circle?
Cheers :D
All you need to do is change this line:
let followCirclePath = SKAction.follow(circlePath, asOffset: false, orientToPath: true, duration: 4)
To this:
let followCirclePath = SKAction.follow(circlePath, asOffset: false, orientToPath: false, duration: 4)
Just set orientToPath to false.
For reference, this is documented by Apple in the following document:
https://developer.apple.com/reference/spritekit/skaction/1417798-follow
Related
This is a wheel I have consisting of four individual sprites. My aim is to rotate them as a wheel. I have tried 'UIBezier' arccenter class but the end result is the individual sprite moving along the center but rotating its shape too, leading to an unwanted result. Here is the relavant code. the 'orientToPath' when set to true, rotates the sprite itself.
//path rotation
let dx = whlPurple.position.x - self.size.width/2
let dy = whlPurple.position.y - (whlRed.size.height/2 + (whlPurple.position.y - whlRed.size.height))
let rad = atan2(dy, dx)
let radius = sqrt((dx*dx) + (dy*dy))
let path = UIBezierPath(arcCenter: CGPoint(x: self.size.width/2, y: (whlRed.size.height/2 + (whlPurple.position.y - whlRed.size.height))), radius: radius, startAngle: rad, endAngle: rad + CGFloat(M_PI * 6), clockwise: true)
let follow = SKAction.follow(path.cgPath, asOffset: false, orientToPath: true, speed: 200)
whlPurple.run(SKAction.repeatForever(follow))
Create an SKNode and place it at the center of your circle.
Then add your sprite to it (addChild) at a position of CGPoint(x:radius,y:0). you can set the zRotation of the SKNode to chose your starting position on the circle.
When you rotate the SKNode, your sprite will move in a perfect circle. For example, to have the spites go around in 5 seconds, you can use SKAction.rotate(by: 2*pi, duration:5) and repeat that forever (on the SKNode containing the sprite (not on the sprite itself).
I am using to following code to make a sprite node move in a circle in Xcode spritekit.
let circleDiameter = CGFloat(100)
// center our path based on our sprites initial position
let pathCenterPoint = CGPoint(
x: object.position.x - circleDiameter,
y: object.position.y - circleDiameter/2)
// create the path our sprite will travel along
let circlePath = CGPath(ellipseIn: CGRect(origin: pathCenterPoint, size: CGSize(width: circleDiameter, height: circleDiameter)), transform: nil)
// create a followPath action for our sprite
let followCirclePath = SKAction.follow(circlePath, asOffset: false, orientToPath: false, duration: 3)
// make our sprite run this action forever
object.run(SKAction.repeatForever(followCirclePath).reversed(), withKey: “moving”)
world.addChild(object)
The problem is, the sprite node starting position is always positioned on the RIGHT side of the circle path. I know I can use .reversed() to change direction of the sprite node but that is not what I am asking.
How can I change the "starting point" to the LEFT side of the circle path?
Thanks Guys! Please refer to the picture below :D
CGPath(ellipseIn:...) is an utility method which creates a path
of an ellipse, where the "argument" or "angle" runs from 0 to 2π.
You cannot add an "offset" to the follow action, but you can define
the path in a way that it starts at the "left end" of the circle:
let circlePath = CGMutablePath()
circlePath.addArc(center: pathCenterPoint, radius: circleDiameter,
startAngle: -.pi, endAngle: .pi, clockwise: false)
I am just starting off with SceneKit and I have some code that renders a cube onto the screen. It shows up find but as soon as I add a camera node the cube no longer appears on screen. Given that I'd set the position of the cube's Node to 0,0,0 and the same for the camera, I cannot figure out what is wrong. I attempted to set the pointOfView property of the SCNView to the camera node but this did not work.
Here is the code for clarification:
func setup() {
box = SCNBox(width: 30, height: 30, length: 30, chamferRadius: 5)
shapeNode.geometry = box
shapeNode.position = SCNVector3(x:0, y:0, z:0)
mainNode.addChildNode(shapeNode)
scene.rootNode.addChildNode(mainNode)
sceneKitView = SCNView(frame:bounds, options:nil)
sceneKitView.autoenablesDefaultLighting = true
sceneKitView.allowsCameraControl = true
sceneKitView.scene = scene
sceneKitView.backgroundColor = UIColor.blackColor()
addSubview(sceneKitView)
// cameraNode.camera = SCNCamera()
// cameraNode.position = SCNVector3Make(0, 0, 10)
// scene.rootNode.addChildNode(cameraNode)
// sceneKitView.pointOfView = cameraNode
}
if both your camera and cube are at (0, 0, 0) then the camera is inside the cube and can't see it. You can make your cube's material doubleSided so that back-facing triangles are visible, but you probably just want to move your camera at something like (0, 0, 100) (a camera's direction of view is along the negative Z axis, and your box has a size of 30).
Alright, so I don't know the name for this but I have a sprite kit game (a runner game) that, when it's game over, is going to have a "save me" button and a timer that runs out accordingly. When the timer runs out, you can no longer click the button and save the character.
I don't want to display this timer in text however- I want a circle that "unwinds itself," if you will, and disappears at the rate that the timer runs out. I.e. when the timer reaches 0, the circle has fully disappeared. The circle disappears degree by degree in a clockwise motion in accordance with the timer.
Here are some pictures to explain what I'm talking about.
How would I do this?
By changing the path property of an SKShapeNode at a fixed interval, you can create a frame-by-frame animation sequence. To create the animation, set the path property to a sequence of shapes that starts with a circle and ends with nothing. You can use UIBezierPath, a wrapper for CGPath, to create shapes for the animation using the following steps:
Move path's "pen" to the center of the circle
Add an arc to the path with addArcWithCenter from a startAngle to endAngle
Add a line to the path from the point on the circle corresponding to the ending angle to the center
Change the endAngle by a fixed amount
Repeat steps 1-4
Here's an implementation of the above steps:
override func didMove(to:SKView) {
let circle = SKShapeNode(circleOfRadius: 50)
circle.fillColor = SKColor.blue
circle.strokeColor = SKColor.clear
circle.zRotation = CGFloat.pi / 2
addChild(circle)
countdown(circle: circle, steps: 20, duration: 5) {
print("done")
}
}
// Creates an animated countdown timer
func countdown(circle:SKShapeNode, steps:Int, duration:TimeInterval, completion:#escaping ()->Void) {
guard let path = circle.path else {
return
}
let radius = path.boundingBox.width/2
let timeInterval = duration/TimeInterval(steps)
let incr = 1 / CGFloat(steps)
var percent = CGFloat(1.0)
let animate = SKAction.run {
percent -= incr
circle.path = self.circle(radius: radius, percent:percent)
}
let wait = SKAction.wait(forDuration:timeInterval)
let action = SKAction.sequence([wait, animate])
run(SKAction.repeat(action,count:steps-1)) {
self.run(SKAction.wait(forDuration:timeInterval)) {
circle.path = nil
completion()
}
}
}
// Creates a CGPath in the shape of a pie with slices missing
func circle(radius:CGFloat, percent:CGFloat) -> CGPath {
let start:CGFloat = 0
let end = CGFloat.pi * 2 * percent
let center = CGPoint.zero
let bezierPath = UIBezierPath()
bezierPath.move(to:center)
bezierPath.addArc(withCenter:center, radius: radius, startAngle: start, endAngle: end, clockwise: true)
bezierPath.addLine(to:center)
return bezierPath.cgPath
}
and a video clip:
I have an SKSpriteNode image with the code:
let Drake1 = SKSpriteNode(imageNamed: "Drake1")
Drake1.position = CGPoint(x:self.frame.size.width/3, y:self.frame.size.height - 230)
Drake1.zPosition = 2
addChild(Drake1)
//drake movement
let moveRight = SKAction.moveByX(frame.size.width/2.8, y: 0, duration: 2)
let moveLeft = SKAction.moveByX(-frame.size.width/2.8, y: 0, duration: 2)
let moveBackAndForth = SKAction.repeatActionForever(SKAction.sequence([moveRight, moveLeft]))
Drake1.runAction(moveBackAndForth)
What I want to do is, when the image is moving to the right, I want to replace the image with a different SKSpriteNode image, and when it moves back left, I want to use the original image, and repeat this forever. I am struggling with what the code should be for this.
SpriteKit comes with a SKAction, setTexture, to instantaneously change a sprite's texture with relative ease. You can create an inline SKTexture object of each images, use them in SKActions, and add them to your sequence loop, like this:
let moveRight = SKAction.moveByX(frame.size.width/2.8, y: 0, duration: 2)
let moveLeft = SKAction.moveByX(-frame.size.width/2.8, y: 0, duration: 2)
let texRight = SKAction.setTexture(SKTexture(imageNamed: "Drake1r"))
let texLeft = SKAction.setTexture(SKTexture(imageNamed: "Drake1l"))
let moveBackAndForth = SKAction.repeatActionForever(SKAction.sequence([texRight, moveRight, texLeft, moveLeft]))
Drake1.runAction(moveBackAndForth)
Hopefully this works for you! Please note that if the textures are different sizes, you must add resize: Bool to setTexture's arguments.