I have a problem where I am spawning balls at the the of the screen and they fall at the standard speed. However, once they reach the bottom, they just fall right through and are removed. How do I make it so that they are kept in the screen?
If it helps, I have a function where I make the ball and set its properties. (similar to a class). Another function where I add the ball to the screen (add child) and make random coords. And a final function where I have the ball endlessly spawn at the top of the screen.
Thanks for your help!
You have to define an physics body edge and set it to the physicsBody of the scene.
let edgeFrame = CGRectMake(0, 0, size.width, size.height)
self.physicsBody = SKPhysicsBody(edgeLoopFromRect: edgeFrame)
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.
I have a construction crane that has a joint with an object. The joint works fine if the crane is stationary.
But I added the ability for the crane to move left to right and whenever the crane is about to leave the view with the object, the object hits the edge of the screen and gets stuck while the crane keeps going. The joint also stops working even after the crane has come back to the view.
Here's an image. The yellow line at the top represents the path the hook follows forever. It goes left to right. The gold block that's around the blue rectangle is what's getting stuck. That's the block that's originally jointed with the crane's gray hook. But when the hook moves to right side of the view, the gold block hits the edge of the screen and stays there forever.
What doesn't make sense to me is that the edge of the view has a category bit mask of 0 while the gold block is at 64. In other levels, the gold blocks NEVER collide with the edge. But here when the crane moves to the edge, the gold block collides with the edge and gets stuck. As you can see, the joints are still there based on the light blue physic lines.
This is the code of the joint being called from the scene and configuring it. Like I said, joint works fine if the hook is stationary.
craneBase.alpha = 0
let path = CGMutablePath()
path.move(to: CGPoint(x: craneBase.position.x, y: craneBase.position.y))
path.addLine(to: CGPoint(x: craneBase.size.width - 100, y: craneBase.position.y + 10))
path.addLine(to: CGPoint(x: craneBase.position.x, y: craneBase.position.y))
craneHook.initializeMovingJoint(withObject: childNode(withName: "HookedObject") as! SKSpriteNode)
hook.run(SKAction.repeatForever(SKAction.follow(path, asOffset: false, orientToPath: false, duration: 10)))
physicsWorld.add(craneHook.joint)
This is the code of the crane's hook class that adds the joint to the block.
private func initHook() {
self.hookSize = CGSize(width: 10, height: 10)
self.physicsBody = SKPhysicsBody(rectangleOf: hookSize)
self.physicsBody?.categoryBitMask = PhysicsBit.none
self.physicsBody?.isDynamic = false
self.physicsBody?.affectedByGravity = false
}
//Creates the joint between the object and the hook
func initializeJoint(withObject object: SKSpriteNode) {
initHook()
hookedObject = object
jointAnchor = CGPoint(x: self.anchorPoint.x, y: self.anchorPoint.y)
joint = SKPhysicsJointFixed.joint(withBodyA: physicsBody!, bodyB: hookedObject.physicsBody!, anchor: jointAnchor)
doesHaveHookedObject = true
}
And the gold block's settings are assigned from the scene editor to a category mask of 64. I've tested the gold blocks and they don't collide with the edge. I'm not sure why it collides with the edge while moving.
I realized it was not working because the joint and the physicsWorld had the same category bit mask. Even though the gold block had a different bit mask, it was part of the joint and thus collided with the same category bit mask as none.
I am trying to add a physicsBody to an SKShapeNode that is a rectangle. I built my PhysicsBody using fromEdgesWithLoop using the Node's frame as the CGRect to build it.
Using the debug option to show PhysicsBody, I see that it is actually not centered on my Sprite.
I searched the web to find that I should use this:
scene.scaleMode = .ResizeFill
Sadly, I tried all scaleModes and there are no differences.
I also verified my GameScene's size and it fits the iPad2 screen (my target), 1024x720.
The SKShapeNode is a child of the Scene.
I tried to set the position of my node in the center of the Scene before adding a PhysicsBody with its frame, but this changed nothing. The node was already in the center of the scene.
myShape.position = CGPointMake(CGRectGetMidX(self.frame), CGRectGetMidY(self.frame))
myShape.physicsBody = SKPhysicsBody(edgeLoopFromRect: myShape.frame)
The position of an Edge Loop is relative to the node it's attached to. In general, for an edgeLoopFromRect, the position is given by
edge_loop_position = node.position + rect.frame.origin
In this case, your physics body is offset by the position of myShape. One way to fix this issue is to attach the edge loop to the scene instead of the shape node:
self.physicsBody = SKPhysicsBody(edgeLoopFromRect: myShape.frame )
Alternatively, you can subtract the node's position from the frame's position with
let rect = CGRect(origin:CGPoint(x:myShape.frame.origin.x-myShape.position.x, y:myShape.frame.origin.y-myShape.position.y), size:myShape.frame.size)
myShape.physicsBody = SKPhysicsBody(edgeLoopFromRect:rect)
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)));