How do I make a simple character controller in SpriteKit? - ios

Question

I'm making a game in sprite kit and in order to move my character I am applying an impulse but that is a problem because that moves him every 50 pixels or so. My question is, could someone please show me how to make a simple character controller so my character can move continuously until the user lets go from holding down the screen?
My GameScene.swift file:
import SpriteKit
class GameScene: SKScene, SKPhysicsContactDelegate {
let character = SKSpriteNode(texture: SKTexture(imageNamed: "character"))
var move = false
override func didMoveToView(view: SKView) {
/* Setup your scene here */
//world
self.physicsWorld.contactDelegate = self
self.physicsBody = SKPhysicsBody(edgeLoopFromRect: self.frame)
//character
character.position = CGPointMake(self.frame.size.width * 0.6, self.frame.size.height * 0.6)
character.setScale(0.2)
character.physicsBody = SKPhysicsBody(rectangleOfSize: character.size)
character.physicsBody?.dynamic = true
character.physicsBody?.allowsRotation = false
self.addChild(character)
character.physicsBody?.affectedByGravity = true
//platform 1
var platform = SKSpriteNode(texture: SKTexture(imageNamed: "platform"))
platform.position = CGPointMake(self.frame.size.width * 0.6, CGRectGetMidY(self.frame))
platform.physicsBody = SKPhysicsBody(rectangleOfSize: platform.size)
platform.physicsBody?.dynamic = false
platform.setScale(0.25)
platform.physicsBody?.friction = 1
platform.physicsBody?.restitution = 0
platform.physicsBody?.linearDamping = 0
self.addChild(platform)
//platform 2
var platformTexture2 = SKTexture(imageNamed: "platform")
var platform2 = SKSpriteNode(texture: platformTexture2)
platform2.position = CGPointMake(self.frame.size.width * 0.4, self.frame.size.height * 0.3)
platform2.physicsBody = SKPhysicsBody(rectangleOfSize: platform2.size)
platform2.physicsBody?.dynamic = false
platform2.setScale(0.25)
platform2.physicsBody?.friction = 1
platform2.physicsBody?.restitution = 0
platform2.physicsBody?.linearDamping = 0
self.addChild(platform2)
//platform main
var platformTexture3 = SKTexture(imageNamed: "platform")
var platform3 = SKSpriteNode(texture: platformTexture2)
platform3.position = CGPointMake(CGRectGetMidX(self.frame), CGRectGetMinY(self.frame) + platform3.size.height / 3)
platform3.physicsBody = SKPhysicsBody(rectangleOfSize: platform3.size)
platform3.physicsBody?.dynamic = false
platform3.setScale(1)
platform3.size.width = platform3.size.width * CGFloat(2.0)
platform3.physicsBody?.friction = 1
platform3.physicsBody?.restitution = 0
platform3.physicsBody?.linearDamping = 0
self.addChild(platform3)
}
override func touchesBegan(touches: Set<NSObject>, withEvent event: UIEvent) {
/* Called when a touch begins */
for touch: AnyObject in touches {
let location = touch.locationInNode(self)
if location.x < CGRectGetMidX(self.frame){
character.physicsBody?.applyImpulse(CGVector(dx: -50, dy: 0))
} else if location.x > CGRectGetMidX(self.frame){
character.physicsBody?.applyImpulse(CGVector(dx: 50, dy: 0))
}
}
func touchesEnded(touches: Set<NSObject>, withEvent event: UIEvent) {
character.physicsBody?.velocity = CGVector(dx: 0, dy: 0)
}
func update(currentTime: CFTimeInterval) {
/* Called before each frame is rendered */
}
};
}

Answer 1

One way to accomplish this is to maintain a variable to keep track of the state of the touch events (left, right, or none). Here are the basic steps:
In touchesBegan, set touch state variable to left or right
In update, apply impulse continuously while user is touching the screen
In touchesEnded, reset the touch state variable
Here's an example of how to implement this...
Above GameScene class definition, add the following
enum TouchState {
case Left
case Right
case None
}
In GameScene, add the following variable
var touchLocation:TouchState = .None
In GameScene, add or replace the following methods
override func update(currentTime: CFTimeInterval) {
// Apply impulse to physics body while users is touching the screen
switch (touchState) {
case .Left:
character.physicsBody?.applyImpulse(CGVector(dx: -1, dy: 0))
case .Right:
character.physicsBody?.applyImpulse(CGVector(dx: 1, dy: 0))
case .None:
break
}
}
override func touchesBegan(touches: Set<NSObject>, withEvent event: UIEvent) {
for touch:AnyObject in touches {
let location = touch.locationInNode(self)
if location.x < CGRectGetMidX(self.frame) {
touchState = .Left
} else if location.x > CGRectGetMidX(self.frame) {
touchState = .Right
}
}
}
override func touchesEnded(touches: Set<NSObject>, withEvent event: UIEvent) {
// Update touch status
touchState = .None
}
Here's the GameScene.swift...
import SpriteKit
enum TouchLocation {
case Left
case Right
case None
}
class GameScene: SKScene, SKPhysicsContactDelegate {
var character = SKSpriteNode(imageNamed: "character")
var touchLocation:TouchLocation = .None
override func didMoveToView(view: SKView) {
/* Setup your scene here */
scaleMode = .ResizeFill
//character
character.position = CGPointMake(view.frame.size.width * 0.5, view.frame.size.height * 0.5)
character.setScale(0.1)
character.physicsBody = SKPhysicsBody(rectangleOfSize: character.size)
character.physicsBody?.dynamic = true
character.physicsBody?.allowsRotation = false
self.addChild(character)
character.physicsBody?.affectedByGravity = true
//platform 1
var platform = SKSpriteNode(texture: SKTexture(imageNamed: "platform"))
platform.position = CGPointMake(view.frame.size.width * 0.6, CGRectGetMidY(view.frame))
platform.physicsBody = SKPhysicsBody(rectangleOfSize: platform.size)
platform.physicsBody?.dynamic = false
platform.setScale(0.25)
platform.physicsBody?.friction = 1
platform.physicsBody?.restitution = 0
platform.physicsBody?.linearDamping = 0
self.addChild(platform)
//platform 2
var platformTexture2 = SKTexture(imageNamed: "platform")
var platform2 = SKSpriteNode(texture: platformTexture2)
platform2.position = CGPointMake(view.frame.size.width * 0.4, view.frame.size.height * 0.3)
platform2.physicsBody = SKPhysicsBody(rectangleOfSize: platform2.size)
platform2.physicsBody?.dynamic = false
platform2.setScale(0.25)
platform2.physicsBody?.friction = 1
platform2.physicsBody?.restitution = 0
platform2.physicsBody?.linearDamping = 0
self.addChild(platform2)
//platform main
var platformTexture3 = SKTexture(imageNamed: "platform")
var platform3 = SKSpriteNode(texture: platformTexture2)
platform3.position = CGPointMake(CGRectGetMidX(view.frame), CGRectGetMinY(view.frame) + platform3.size.height / 3)
platform3.physicsBody = SKPhysicsBody(rectangleOfSize: platform3.size)
platform3.physicsBody?.dynamic = false
platform3.setScale(1)
platform3.size.width = platform3.size.width * CGFloat(2.0)
platform3.physicsBody?.friction = 1
platform3.physicsBody?.restitution = 0
platform3.physicsBody?.linearDamping = 0
self.addChild(platform3)
}
override func update(currentTime: CFTimeInterval) {
/* Called before each frame is rendered */
switch (touchLocation) {
case .Left:
character.physicsBody?.applyImpulse(CGVector(dx: -1, dy: 0))
case .Right:
character.physicsBody?.applyImpulse(CGVector(dx: 1, dy: 0))
case .None:
break
}
}
override func touchesBegan(touches: Set<NSObject>, withEvent event: UIEvent) {
for touch:AnyObject in touches {
let location = touch.locationInNode(self)
if location.x < CGRectGetMidX(self.frame) {
touchLocation = .Left
} else if location.x > CGRectGetMidX(self.frame) {
touchLocation = .Right
}
}
}
override func touchesEnded(touches: Set<NSObject>, withEvent event: UIEvent) {
touchLocation = .None
}
}