The below class attaches to a UIView and draws lines while moving a finger across the screen. However, when moving a finger very fast from left to right moving from top to bottom, the drawing temporarily shows sharp pointy edges on changing direction. This occurs both on the device and simulator.
What is causing this issue and how can this artefact be eliminated in the code so that only smooth rounded, not sharp edges are seen when changing direction fast?
class drawLine: UIView
{
var comittedSegments: Int = 0
var points = [CGPoint]()
var committedPath = UIBezierPath()
var drawPath = UIBezierPath()
var incrementalImage: UIImage?
var strokeColor:UIColor?
override func drawRect(rect: CGRect) {
autoreleasepool {
incrementalImage?.drawInRect(rect)
strokeColor = UIColor.darkGrayColor()
strokeColor?.setStroke()
drawPath.lineWidth = 20
drawPath.lineCapStyle = CGLineCap.Round
drawPath.stroke()
}
}
override func touchesBegan(touches: Set<UITouch>, withEvent event: UIEvent?) {
let touch: AnyObject? = touches.first
comittedSegments = 0
committedPath.removeAllPoints()
points.removeAll()
points.append( touch!.locationInView(self) )
}
override func touchesMoved(touches: Set<UITouch>, withEvent event: UIEvent?) {
let touch: AnyObject? = touches.first
let point = touch!.locationInView(self)
points.append( point )
if points.count == 5
{
points[3] = CGPointMake((points[2].x + points[4].x)/2.0, (points[2].y + points[4].y)/2.0)
committedPath.moveToPoint(points[0])
committedPath.addCurveToPoint(points[3], controlPoint1: points[1], controlPoint2: points[2])
comittedSegments = comittedSegments + 1
self.setNeedsDisplay()
points[0] = points[3]
points[1] = points[4]
points.removeRange(2...4)
drawPath = committedPath
}
else if points.count > 1
{
drawPath = committedPath.copy() as! UIBezierPath
drawPath.CGPath = committedPath.CGPath
drawPath.moveToPoint( points[0] )
for point in points[1..<points.count] {
drawPath.addLineToPoint(point)
}
self.setNeedsDisplay()
}
}
override func touchesEnded(touches: Set<UITouch>, withEvent event: UIEvent?) {
self.drawBitmap()
self.setNeedsDisplay()
committedPath.removeAllPoints()
points.removeAll()
}
override func touchesCancelled(touches: Set<UITouch>?, withEvent event: UIEvent?) {
self.touchesEnded(touches!, withEvent: event)
}
func drawBitmap() {
UIGraphicsBeginImageContextWithOptions(self.bounds.size, true, 0.0)
strokeColor?.setStroke()
if(incrementalImage == nil) {
let rectPath:UIBezierPath = UIBezierPath(rect: self.bounds)
UIColor.whiteColor().setFill()
rectPath.fill()
}
incrementalImage?.drawAtPoint(CGPointZero)
committedPath.stroke()
incrementalImage = UIGraphicsGetImageFromCurrentImageContext()
UIGraphicsEndImageContext()
}
}
In addition to setting lineCapStyle, set lineJoinStyle:
drawPath.lineJoinStyle = .Round
drawPath.lineCapStyle = .Round
Related
I would like to have the following interplay between line and ball in my game: a line gives direction and speed to the ball. The longer the line, the faster the ball.
What I have now: a ball is following the line and stops at the end of it. But it shouldn't stop here. Of course, I understand that the ball is only following the path I made. But how could I change it?
Here is my code:
import SpriteKit
import GameplayKit
class GameScene: SKScene, SKPhysicsContactDelegate {
// Basic for dynamic sizes step01
var width = CGFloat()
var height = CGFloat()
var ball:SKSpriteNode!
var line:SKShapeNode!
var startPoint: CGPoint!
var location = CGPoint()
override func didMove(to view: SKView) {
self.backgroundColor = .purple
//declare dynamic size of the screen
width = self.frame.size.width
height = self.frame.size.height
self.physicsBody = SKPhysicsBody(edgeLoopFrom: frame)
self.physicsWorld.gravity = CGVector.zero
createBall()
}
func createBall(){
ball = SKSpriteNode(imageNamed: "yellowBtn")
ball.position = CGPoint(x:0, y: -(height/2.5))
ball.size = CGSize(width: width/6, height: width/6)
self.addChild(ball)
}
func drawLine(endPoint:CGPoint){
if(line != nil ){ line.removeFromParent() }
startPoint = ball.position
let path = CGMutablePath()
path.move(to: startPoint)
path.addLine(to: endPoint)
line = SKShapeNode()
line.path = path
line.lineWidth = 5
line.strokeColor = UIColor.white
self.addChild(line)
}
override func touchesBegan(_ touches: Set<UITouch>, with event: UIEvent?) {
if(line != nil ){ line.removeFromParent()
for touch in (touches ) {
let location = touch.location(in: self)
drawLine(endPoint: location)
}
}
}
override func touchesMoved(_ touches: Set<UITouch>, with event: UIEvent?) {
for touch in (touches ) {
let location = touch.location(in: self)
drawLine(endPoint: location)
}
}
override func touchesEnded(_ touches: Set<UITouch>, with event: UIEvent?) {
for touch in (touches ) {
location = touch.location(in: self)
drawLine(endPoint: location)
}
let moveAction = SKAction.move(to: location, duration: 10)
ball.run(moveAction)
}
override func update(_ currentTime: TimeInterval) {
}
}
I have found at least a part of answer to my question: I need to calculate CGVector manually (lastPoint - firstPoint) and then apply impulse to the ball:
override func touchesEnded(_ touches: Set<UITouch>, with event: UIEvent?) {
for touch in (touches ) {
location = touch.location(in: self)
drawLine(endPoint: location)
}
let dx = location.x - startPoint.x
let dy = location.y - startPoint.y
let movement = CGVector(dx: dx, dy: dy)
ball.physicsBody = SKPhysicsBody(circleOfRadius: 50)
ball.physicsBody?.applyImpulse(movement)
}
Now I should find the second part: how to set the speed of the ball accordingly to the length of the line.
I have been having some trouble moving a Sprite along a UIBezierPath. I am getting this path from my view controller and it is passing along the correct path. Any ideas on why this isn't animating? Eventually I want to be able to move multiple sprites along different bezier paths.
func play(){
let img = SKSpriteNode(imageNamed:"ball.png")
img.position = CGPoint(x: self.frame.size.width/4, y: self.frame.size.height/4)
self.addChild(img)
new_path = viewController.path //UIBezierPath is being returned
let followPath = SKAction.follow(new_path.cgPath, asOffset: true, orientToPath: false, duration: 5.0)
img.run(followPath)
}
I am trying to draw a bezier path here(Kind of like a whiteboard app)in a custom view and then access the bezier path when I want to animate it. The path seems to be passed through correctly.
private var path: UIBezierPath!
let newpath = UIBezierPath()
func initBezierPath() {
path = UIBezierPath()
path.lineCapStyle = CGLineCap.round
path.lineJoinStyle = CGLineJoin.round
}
override func touchesBegan(_ touches: Set<UITouch>, with event: UIEvent?) {
let touch: AnyObject? = touches.first
lastPoint = touch!.location(in: self)
pointCounter = 0
}
override func touchesMoved(_ touches: Set<UITouch>, with event: UIEvent?) {
let touch: AnyObject? = touches.first
let newPoint = touch!.location(in: self)
path.move(to: lastPoint)
path.addLine(to: newPoint)
lastPoint = newPoint
pointCounter += 1
if pointCounter == pointLimit {
pointCounter = 0
renderToImage()
setNeedsDisplay()
newpath.append(path)
path.removeAllPoints()
}
else {
setNeedsDisplay()
}
}
override func touchesEnded(_ touches: Set<UITouch>, with event: UIEvent?) {
pointCounter = 0
renderToImage()
setNeedsDisplay()
newpath.append(path)
path.removeAllPoints()
}
The code below draws smooth curved lines by overriding touches, but there is noticeable lagging or latency. The code uses addCurveToPoint and calls setNeedsDisplay after every 4 touch points which causes a jumpy appearance as the drawing doesn't keep up with finger movements. To remove the lagging or perceived latency, touch points 1, 2, 3 (leading up to touch point 4) could be temporarily filled with addQuadCurveToPoint and addLineToPoint.
How can this actually be achieved in code to remove perceived lagging by using a temporary Line and QuadCurved line before displaying a final Curved line?
If the below class is attached to one UIView (e.g. viewOne or self), how do I make a copy of the drawing to another UIView outside the class (e.g. viewTwo) after touchesEnded?
// ViewController.swift
import UIKit
class drawSmoothCurvedLinesWithLagging: UIView {
let path=UIBezierPath()
var incrementalImage:UIImage?
var points = [CGPoint?](count: 5, repeatedValue: nil)
var counter:Int?
var strokeColor:UIColor?
required init?(coder aDecoder: NSCoder) {
super.init(coder: aDecoder)
}
override func drawRect(rect: CGRect) {
autoreleasepool {
incrementalImage?.drawInRect(rect)
strokeColor = UIColor.blueColor()
strokeColor?.setStroke()
path.lineWidth = 20
path.lineCapStyle = CGLineCap.Round
path.stroke()
}
}
override func touchesBegan(touches: Set<UITouch>, withEvent event: UIEvent?) {
counter = 0
let touch: AnyObject? = touches.first
points[0] = touch!.locationInView(self)
}
override func touchesMoved(touches: Set<UITouch>, withEvent event: UIEvent?) {
let touch: AnyObject? = touches.first
let point = touch!.locationInView(self)
counter = counter! + 1
points[counter!] = point
if counter == 2{
//use path.addLineToPoint ?
//use self.setNeedsDisplay() ?
}
if counter == 3{
//use path.addQuadCurveToPoint ?
//use self.setNeedsDisplay() ?
}
if counter == 4{
points[3]! = CGPointMake((points[2]!.x + points[4]!.x)/2.0, (points[2]!.y + points[4]!.y)/2.0)
path.moveToPoint(points[0]!)
path.addCurveToPoint(points[3]!, controlPoint1: points[1]!, controlPoint2: points[2]!)
self.setNeedsDisplay()
points[0]! = points[3]!
points[1]! = points[4]!
counter = 1
}
}
override func touchesEnded(touches: Set<UITouch>, withEvent event: UIEvent?) {
self.drawBitmap()
self.setNeedsDisplay()
path.removeAllPoints()
counter = 0
}
override func touchesCancelled(touches: Set<UITouch>?, withEvent event: UIEvent?) {
self.touchesEnded(touches!, withEvent: event)
}
func drawBitmap(){
UIGraphicsBeginImageContextWithOptions(self.bounds.size, true, 0.0)
strokeColor?.setStroke()
if((incrementalImage) == nil){
let rectPath:UIBezierPath = UIBezierPath(rect: self.bounds)
UIColor.whiteColor().setFill()
rectPath.fill()
}
incrementalImage?.drawAtPoint(CGPointZero)
path.stroke()
incrementalImage = UIGraphicsGetImageFromCurrentImageContext()
UIGraphicsEndImageContext()
}
}
class ViewController: UIViewController {
override func viewDidLoad() {
super.viewDidLoad()
// Do any additional setup after loading the view, typically from a nib.
}
override func didReceiveMemoryWarning() {
super.didReceiveMemoryWarning()
// Dispose of any resources that can be recreated.
}
}
Yes, adding a curve every few points will give it a stuttering lag. So, yes, you can reduce this affect by adding a line to points[1], adding a quad curve to points[2] and adding a cubic curve to points[3].
As you said, make sure to add this to a separate path, though. So, in Swift 3/4:
class SmoothCurvedLinesView: UIView {
var strokeColor = UIColor.blue
var lineWidth: CGFloat = 20
var snapshotImage: UIImage?
private var path: UIBezierPath?
private var temporaryPath: UIBezierPath?
private var points = [CGPoint]()
override func draw(_ rect: CGRect) {
snapshotImage?.draw(in: rect)
strokeColor.setStroke()
path?.stroke()
temporaryPath?.stroke()
}
override func touchesBegan(_ touches: Set<UITouch>, with event: UIEvent?) {
if let touch = touches.first {
points = [touch.location(in: self)]
}
}
override func touchesMoved(_ touches: Set<UITouch>, with event: UIEvent?) {
guard let touch = touches.first else { return }
let point = touch.location(in: self)
points.append(point)
updatePaths()
setNeedsDisplay()
}
private func updatePaths() {
// update main path
while points.count > 4 {
points[3] = CGPoint(x: (points[2].x + points[4].x)/2.0, y: (points[2].y + points[4].y)/2.0)
if path == nil {
path = createPathStarting(at: points[0])
}
path?.addCurve(to: points[3], controlPoint1: points[1], controlPoint2: points[2])
points.removeFirst(3)
temporaryPath = nil
}
// build temporary path up to last touch point
if points.count == 2 {
temporaryPath = createPathStarting(at: points[0])
temporaryPath?.addLine(to: points[1])
} else if points.count == 3 {
temporaryPath = createPathStarting(at: points[0])
temporaryPath?.addQuadCurve(to: points[2], controlPoint: points[1])
} else if points.count == 4 {
temporaryPath = createPathStarting(at: points[0])
temporaryPath?.addCurve(to: points[3], controlPoint1: points[1], controlPoint2: points[2])
}
}
override func touchesEnded(_ touches: Set<UITouch>, with event: UIEvent?) {
finishPath()
}
override func touchesCancelled(_ touches: Set<UITouch>?, with event: UIEvent?) {
finishPath()
}
private func finishPath() {
constructIncrementalImage()
path = nil
setNeedsDisplay()
}
private func createPathStarting(at point: CGPoint) -> UIBezierPath {
let localPath = UIBezierPath()
localPath.move(to: point)
localPath.lineWidth = lineWidth
localPath.lineCapStyle = .round
localPath.lineJoinStyle = .round
return localPath
}
private func constructIncrementalImage() {
UIGraphicsBeginImageContextWithOptions(bounds.size, false, 0.0)
strokeColor.setStroke()
snapshotImage?.draw(at: .zero)
path?.stroke()
temporaryPath?.stroke()
snapshotImage = UIGraphicsGetImageFromCurrentImageContext()
UIGraphicsEndImageContext()
}
}
You could even marry this with iOS 9 predictive touches (as I described in my other answer), which could reduce lag even further.
To take this resulting image and use it elsewhere, you can just grab the incrementalImage (which I renamed to snapshotImage, above), and drop it into an image view of the other view.
For Swift 2 rendition, see previous revision of this answer.
I'm trying to make a drawing app. I have a single custom UIView:
class DrawView: UIView {
var touch : UITouch!
var lastPoint : CGPoint!
var currentPoint : CGPoint!
override func touchesBegan(touches: Set<NSObject>, withEvent event: UIEvent) {
touch = touches.first as! UITouch
lastPoint = touch.locationInView(self)
println(lastPoint)
}
override func touchesMoved(touches: Set<NSObject>, withEvent event: UIEvent) {
touch = touches.first as! UITouch
currentPoint = touch.locationInView(self)
self.setNeedsDisplay()
lastPoint = currentPoint
}
override func drawRect(rect: CGRect) {
var context = UIGraphicsGetCurrentContext()
CGContextSetLineWidth(context, 5)
CGContextSetStrokeColorWithColor(context, UIColor.blueColor().CGColor)
CGContextSetLineCap(context, kCGLineCapRound)
CGContextBeginPath(context)
if lastPoint != nil {
CGContextMoveToPoint(context, lastPoint.x, lastPoint.y)
CGContextAddLineToPoint(context, currentPoint.x, currentPoint.y)
}
CGContextStrokePath(context)
}
}
When I run it, however, all I get is a blue dot that follows my finger, but no lines?
What am I doing wrong?
Hi i make some simple changes and fixed your code, hope it helps someone in the future (code it's updated for Swift 3) :
class DrawView: UIView {
var touch : UITouch!
var lineArray : [[CGPoint]] = [[CGPoint]()]
var index = -1
override func touchesBegan(_ touches: Set<UITouch>, with event: UIEvent?) {
touch = touches.first! as UITouch
let lastPoint = touch.location(in: self)
index += 1
lineArray.append([CGPoint]())
lineArray[index].append(lastPoint)
}
override func touchesMoved(_ touches: Set<UITouch>, with event: UIEvent?) {
touch = touches.first! as UITouch
let currentPoint = touch.location(in: self)
self.setNeedsDisplay()
lineArray[index].append(currentPoint)
}
override func draw(_ rect: CGRect) {
if(index >= 0){
let context = UIGraphicsGetCurrentContext()
context!.setLineWidth(5)
context!.setStrokeColor((UIColor(red:0.00, green:0.38, blue:0.83, alpha:1.0)).cgColor)
context!.setLineCap(.round)
var j = 0
while( j <= index ){
context!.beginPath()
var i = 0
context?.move(to: lineArray[j][0])
while(i < lineArray[j].count){
context?.addLine(to: lineArray[j][i])
i += 1
}
context!.strokePath()
j += 1
}
}
}
}
Two things:
Calling self.setNeedsDisplay doesn't immediately call drawRect. It just sets a flag so that drawRect will be called in the near future. Since you set lastPoint to currentPoint right after that, when drawRect is called lastPoint is always equal to currentPoint.
drawRect redraws the entire view every time it is called, so at most you'd only ever see the most recent line. If you fixed problem 1, you'd have a short line following your finger instead of a dot. If you want to see the whole trail, you'll need to store the points in an array that is a property of your view, and then draw lines to connect all of the points in drawRect.
marcomoreira92 and Keuha's version worked for me, but I don't like to use indices that much. Thus here is an alternative version, which was tested in Swift 4.2:
class DrawView: UIView {
var lineArray: [[CGPoint]] = [[CGPoint]]()
override func touchesBegan(_ touches: Set<UITouch>, with event: UIEvent?) {
guard let touch = touches.first else { return }
let firstPoint = touch.location(in: self)
lineArray.append([CGPoint]())
lineArray[lineArray.count - 1].append(firstPoint)
}
override func touchesMoved(_ touches: Set<UITouch>, with event: UIEvent?) {
guard let touch = touches.first else { return }
let currentPoint = touch.location(in: self)
lineArray[lineArray.count - 1].append(currentPoint)
setNeedsDisplay()
}
override func draw(_ rect: CGRect) {
let context = UIGraphicsGetCurrentContext()
context?.setLineWidth(5)
context?.setStrokeColor(UIColor.black.cgColor)
context?.setLineCap(.round)
for line in lineArray {
guard let firstPoint = line.first else { continue }
context?.beginPath()
context?.move(to: firstPoint)
for point in line.dropFirst() {
context?.addLine(to: point)
}
context?.strokePath()
}
}
}
I have the following code at the moment. Even though the code build is successful, i cannot seem to get it to work. I am trying to make it so when you flick the object, it moves at the velocity of your begin and end touch.
import SpriteKit
class GameScene: SKScene {
var sprite: SKSpriteNode!
var touchPoint: CGPoint = CGPoint()
var touching: Bool = false
override func didMoveToView(view: SKView) {
self.physicsBody = SKPhysicsBody(edgeLoopFromRect: self.frame)
sprite = SKSpriteNode(color: UIColor.redColor(), size: CGSize(width: 50, height: 50))
sprite.physicsBody = SKPhysicsBody(rectangleOfSize: sprite.size)
sprite.position = CGPoint(x: self.size.width/2.0, y: self.size.height/2.0)
self.addChild(sprite)
}
//for touch: AnyObject in touches {
//let location = touch.locationInNode(self)
//let touchedNode = self.nodeAtPoint(location)
override func touchesBegan(touches: Set<NSObject>, withEvent event: UIEvent) {
for touch: AnyObject in touches {
let location = touch.locationInNode(self)
if sprite.frame.contains(location) {
touchPoint = location
touching = true
}
}
func touchesMoved(touches: Set<NSObject>, withEvent event: UIEvent) {
for touch: AnyObject in touches {
let location = touch.locationInNode(self)
touchPoint = location
}
func touchesEnded(touches: Set<NSObject>, withEvent event: UIEvent) {
touching = false
}
func update(currentTime: CFTimeInterval) {
if touching {
let dt:CGFloat = 1.0/60.0
let distance = CGVector(dx: touchPoint.x-sprite.position.x, dy: touchPoint.y-sprite.position.y)
let velocity = CGVector(dx: distance.dx/dt, dy: distance.dy/dt)
sprite.physicsBody!.velocity = velocity
}
}
}}}
You accidentally placed touchesMoved, touchesEnded and update inside touchesBegan. Besides that your code works. A hint that there were problems was the fact you didn't need to prefix touchesMoved, touchesEnded or update with override.
In the future, I would recommend using breakpoints and print statements to check the methods you expect to execute, are in fact running. Doing that you'd see that your versions of touchesMoved, touchesEnded and update weren't being called.
Anyway, here's it corrected it and now it works perfectly:
import SpriteKit
class GameScene: SKScene {
var sprite: SKSpriteNode!
var touchPoint: CGPoint = CGPoint()
var touching: Bool = false
override func didMoveToView(view: SKView) {
self.physicsBody = SKPhysicsBody(edgeLoopFromRect: self.frame)
sprite = SKSpriteNode(color: UIColor.redColor(), size: CGSize(width: 50, height: 50))
sprite.physicsBody = SKPhysicsBody(rectangleOfSize: sprite.size)
sprite.position = CGPoint(x: self.size.width/2.0, y: self.size.height/2.0)
self.addChild(sprite)
}
override func touchesBegan(touches: Set<NSObject>, withEvent event: UIEvent) {
for touch: AnyObject in touches {
let location = touch.locationInNode(self)
if sprite.frame.contains(location) {
touchPoint = location
touching = true
}
}
}
override func touchesMoved(touches: Set<NSObject>, withEvent event: UIEvent) {
for touch: AnyObject in touches {
let location = touch.locationInNode(self)
touchPoint = location
}
}
override func touchesEnded(touches: Set<NSObject>, withEvent event: UIEvent) {
touching = false
}
override func touchesCancelled(touches: Set<NSObject>!, withEvent event: UIEvent!) {
touching = false
}
override func update(currentTime: NSTimeInterval) {
if touching {
let dt:CGFloat = 1.0/60.0
let distance = CGVector(dx: touchPoint.x-sprite.position.x, dy: touchPoint.y-sprite.position.y)
let velocity = CGVector(dx: distance.dx/dt, dy: distance.dy/dt)
sprite.physicsBody!.velocity = velocity
}
}
}
ABakerSmith's solutions updated for Swift 4:
import SpriteKit
class GameScene: SKScene {
var sprite: SKSpriteNode!
var touchPoint: CGPoint = CGPoint()
var touching: Bool = false
override func didMove(to view: SKView) {
self.physicsBody = SKPhysicsBody.init(edgeLoopFrom: self.frame)
sprite = SKSpriteNode(color: .red, size: CGSize(width: 50, height: 50))
sprite.physicsBody = SKPhysicsBody.init(rectangleOf: sprite.size)
sprite.position = CGPoint(x: self.size.width/2.0, y: self.size.height/2.0)
self.addChild(sprite)
}
override func touchesBegan(_ touches: Set<UITouch>, with event: UIEvent?) {
if let touch = touches.first?.location(in: self) {
if sprite.frame.contains(touch) {
touchPoint = touch
touching = true
}
}
}
override func touchesMoved(_ touches: Set<UITouch>, with event: UIEvent?) {
for t in touches {
let location = t.location(in: self)
touchPoint = location
}
}
override func touchesEnded(_ touches: Set<UITouch>, with event: UIEvent?) {
touching = false
}
override func touchesCancelled(_ touches: Set<UITouch>, with event: UIEvent?) {
touching = false
}
override func update(_ currentTime: TimeInterval) {
if touching {
let dt:CGFloat = 1.0/60.0
let distance = CGVector(dx: touchPoint.x-sprite.position.x, dy: touchPoint.y-sprite.position.y)
let velocity = CGVector(dx: distance.dx/dt, dy: distance.dy/dt)
sprite.physicsBody!.velocity = velocity
}
}
}
Solution updated to not have the touch/drag snap to the middle of the sprite. If you're dragging/throwing an object you're going to want that throw to come from where the user touched the object and not snap to the middle of the object. This will make it look a lot smoother
import SpriteKit
class GameScene: SKScene {
var sprite: SKSpriteNode!
var touchPoint: CGPoint = CGPoint()
var touching: Bool = false
var xDif = CGFloat()
var yDif = CGFloat()
override func didMove(to view: SKView) {
self.physicsBody = SKPhysicsBody.init(edgeLoopFrom: self.frame)
sprite = SKSpriteNode(color: .red, size: CGSize(width: 50, height: 50))
sprite.physicsBody = SKPhysicsBody.init(rectangleOf: sprite.size)
sprite.position = CGPoint(x: self.size.width/2.0, y: self.size.height/2.0)
self.addChild(sprite)
}
override func touchesBegan(_ touches: Set<UITouch>, with event: UIEvent?) {
if let touch = touches.first?.location(in: self) {
xDif = sprite.position.x - touch.x
yDif = sprite.position.y - touch.y
if sprite.frame.contains(touch) {
touchPoint = touch
touching = true
}
}
}
override func touchesMoved(_ touches: Set<UITouch>, with event: UIEvent?) {
for t in touches {
let location = t.location(in: self)
touchPoint = location
}
}
override func touchesEnded(_ touches: Set<UITouch>, with event: UIEvent?) {
touching = false
}
override func touchesCancelled(_ touches: Set<UITouch>, with event: UIEvent?) {
touching = false
}
override func update(_ currentTime: TimeInterval) {
if touching {
let dt:CGFloat = 1.0/60.0
let distance = CGVector(dx: touchPoint.x-sprite.position.x + xDif, dy: touchPoint.y-sprite.position.y + yDif)
let velocity = CGVector(dx: distance.dx/dt, dy: distance.dy/dt)
sprite.physicsBody!.velocity = velocity
}
}
}