Sprite Kit set Min. and Max. for Jump

Question

I want to move a SKSpriteNode on the Y-Axis. The SKSpriteNode called Player has no Velocity.The Player can only jump if a Platform is in contact.

Everytime the Screen is touched, I want to give the Player an impulse with a minimum impulse or a maximum impulse

If the Screen is tapped shortly, the Minimum impulse should be e.g. y = 50. If the Screen is hold, that means the finger is on the Screen long, the Maximum should be e.g. y = 100.

But the Player should be also able to jump between the Minimum and Maximum height, if for e.g. the Screen is not long but also not shortly pressed, the Player should only get an impulse of y = 70.

If the Screen is hold, the Player should jump to his max height, fall down, and if it is in contact with the Platform again, it should jump, because you still hold the Screen.

I have already tried this with the suggested answer in this Thread:StackOverFlow But this does not give the Minimum jump, also no Press jump.

For clarity: The impulse should not be after the tap is done, but while it is tapped. The longer you hold, the longer the jump is.

import SpriteKit
import GameKit

struct Constants {

static let minimumJumpForce:CGFloat = 40.0
static let maximumJumpForce:CGFloat = 60.0
static let characterSideSpeed:CGFloat = 18.0
}

class GameScene: SKScene, SKPhysicsContactDelegate {

var Player: SKSpriteNode!

var Platform0: SKSpriteNode!

var World: SKNode!
var Camera: SKNode!

var force: CGFloat = 40.0

var pressed = false

var isCharacterOnGround = false

.....

func SpawnPlatforms() {

Platform0 = SKSpriteNode (color: SKColor.greenColor(), size: CGSize(width: self.frame.size.width , height: 25))
Platform0.position = CGPoint(x: self.frame.size.width / 2, y: -36)
Platform0.zPosition = 1

Platform0.physicsBody = SKPhysicsBody(rectangleOfSize:Platform0.size)
Platform0.physicsBody?.dynamic = false
Platform0.physicsBody?.allowsRotation = false
Platform0.physicsBody?.restitution = 0
Platform0.physicsBody?.usesPreciseCollisionDetection = true

Platform0.physicsBody?.categoryBitMask = Platform0Category
Platform0.physicsBody?.collisionBitMask = PlayerCategory
Platform0.physicsBody?.contactTestBitMask = PlayerCategory

World.addChild(Platform0)

}

func SpawnPlayer(){

Player = SKSpriteNode (imageNamed: "Image.png")
Player.size = CGSize(width: 64, height: 64)
Player.position = CGPoint(x: self.frame.size.width / 2, y: 0)
Player.zPosition = 2

Player.physicsBody = SKPhysicsBody(rectangleOfSize:CGSize(width: 35, height: 50))
Player.physicsBody?.dynamic = true
Player.physicsBody?.allowsRotation = false
Player.physicsBody?.restitution = 0.1
Player.physicsBody?.usesPreciseCollisionDetection = true

Player.physicsBody?.categoryBitMask = PlayerCategory
Player.physicsBody?.collisionBitMask = Platform0Category
Player.physicsBody?.contactTestBitMask = Platform0Category | Platform1Category | Platform2Category | Platform3Category | Platform4Category | Platform5Category

World.addChild(Player)

}

func jump(force : CGFloat){


    if(self.isCharacterOnGround){

        self.Player.physicsBody?.applyImpulse(CGVectorMake(0, force))
        self.isCharacterOnGround = false
    }

}

override func touchesBegan(touches: Set<NSObject>, withEvent event: UIEvent) {
    /* Called when a touch begins */

    for touch in (touches as! Set<UITouch>) {
        let location = touch.locationInNode(self)

        self.pressed = true

        let timerAction = SKAction.waitForDuration(0.0)

        let update = SKAction.runBlock({
            if(self.force < Constants.maximumJumpForce){
                self.force += 2.0
            }else{
                self.jump(Constants.maximumJumpForce)
                self.force = Constants.maximumJumpForce
            }
        })
        let sequence = SKAction.sequence([timerAction, update])
        let repeat = SKAction.repeatActionForever(sequence)
        self.runAction(repeat, withKey:"repeatAction")
    }
}

override func touchesEnded(touches: Set<NSObject>, withEvent event: UIEvent) {
    for touch in (touches as! Set<UITouch>) {
        let location = touch.locationInNode(self)

        self.removeActionForKey("repeatAction")

        self.jump(self.force)

        self.force = Constants.minimumJumpForce

        self.pressed = false

}
}

func didBeginContact(contact: SKPhysicsContact) {

    //this gets called automatically when two objects begin contact with each other

    let contactMask = contact.bodyA.categoryBitMask | contact.bodyB.categoryBitMask

    switch(contactMask) {

    case PlayerCategory | Platform0Category:
        //either the contactMask was the bro type or the ground type
        println("Contact Made0")
        Green = true
        self.isCharacterOnGround = true

    default:
        return

    }

}

Answer 1

Here is an working example on how to make something like:

• long pressed jump based on duration of press
• short (one tap jump)
• restrict character to jump while in the air

• keep character jumping while finger is on screen

  import SpriteKit
  
      struct Constants {
  
          static let minimumJumpForce:CGFloat = 15.0
          static let maximumJumpForce:CGFloat = 30.0
          static let characterSideSpeed:CGFloat = 18.0
      }
  
      class GameScene: SKScene,SKPhysicsContactDelegate
      {
          let CharacterCategory   : UInt32 = 0x1 << 1
          let PlatformCategory    : UInt32 = 0x1 << 2
          let WallCategory        : UInt32 = 0x1 << 3
  
          var force: CGFloat = 16.0 //Initial force
  
          var pressed = false
  
          var isCharacterOnGround = false // Use this to prevent jumping while in the air
  
          let character = SKSpriteNode(color: SKColor.greenColor(), size: CGSize(width: 30, height:30))
  
  
          let   debugLabel = SKLabelNode(fontNamed: "Geneva")
  
          override func didMoveToView(view: SKView)
          {
              //Setup contact delegate so we can use didBeginContact and didEndContact methods
              physicsWorld.contactDelegate = self
              physicsWorld.speed = 0.5
              //Setup borders so character can't escape from us :-)
              self.physicsBody = SKPhysicsBody(edgeLoopFromRect: self.frame)
              self.physicsBody?.categoryBitMask = WallCategory
              self.physicsBody?.collisionBitMask = CharacterCategory
  
  
              //Setup character
              character.position = CGPoint(x: 150, y: 150)
              character.physicsBody = SKPhysicsBody(rectangleOfSize: character.size)
              character.physicsBody?.categoryBitMask = CharacterCategory
              character.physicsBody?.contactTestBitMask = PlatformCategory
              character.physicsBody?.collisionBitMask = PlatformCategory | WallCategory
              character.physicsBody?.allowsRotation = false
              character.physicsBody?.dynamic = true
              character.physicsBody?.restitution = 0.1
  
              self.addChild(character)
  
              generatePlatforms()
  
              debugLabel.text = " DEBUG: "
              debugLabel.fontColor = SKColor.whiteColor()
              debugLabel.fontSize = 12.0
              debugLabel.position = CGPoint(x: CGRectGetMidX(frame), y: CGRectGetMidY(frame)+100)
              self.addChild(debugLabel)
  
  
          }
  
          func generatePlatforms(){
  
  
              for i in 1...4
              {
  
  
  
                  let position = CGPoint(x: CGRectGetMidX(frame), y: CGFloat(i)*140.0 - 100)
  
                  let platform = createPlatformAtPosition(position)
  
                  self.addChild(platform)
  
              }
  
  
          }
  
  
          func createPlatformAtPosition(position : CGPoint)->SKSpriteNode{
  
              let platform = SKSpriteNode(color: SKColor.greenColor(), size: CGSize(width:frame.size.width, height:20))
  
              platform.position = position
  
              platform.physicsBody = SKPhysicsBody(
                  edgeFromPoint: CGPoint(x: -platform.size.width/2.0, y:platform.size.height/2.0),
                  toPoint:CGPoint(x: platform.size.width/2.0, y: platform.size.height/2.0))
  
              platform.physicsBody?.categoryBitMask       = PlatformCategory
              platform.physicsBody?.contactTestBitMask    = CharacterCategory
              platform.physicsBody?.collisionBitMask      = CharacterCategory
              platform.physicsBody?.allowsRotation        = false
              platform.name = "platform"
              platform.physicsBody?.dynamic               = false
              platform.physicsBody?.restitution = 0.0
  
              return platform
          }
  
          func jump(force : CGFloat){
  
  
              if(self.isCharacterOnGround){
  
                  self.character.physicsBody?.applyImpulse(CGVectorMake(0, force))
                  self.character.physicsBody?.collisionBitMask = WallCategory
                  self.isCharacterOnGround = false
              }
  
          }
  
          override func touchesBegan(touches: NSSet, withEvent event: UIEvent) {
  
              self.pressed = true
  
              let timerAction = SKAction.waitForDuration(0.05)
  
              let update = SKAction.runBlock({
                  if(self.force < Constants.maximumJumpForce){
                      self.force += 2.0
                  }else{
  
  
  
                    self.jump(Constants.maximumJumpForce)
  
                    self.force = Constants.maximumJumpForce
  
  
                  }
              })
              let sequence = SKAction.sequence([timerAction, update])
              let repeat = SKAction.repeatActionForever(sequence)
              self.runAction(repeat, withKey:"repeatAction")
  
          }
  
  
          override func touchesEnded(touches: NSSet, withEvent event: UIEvent) {
  
              self.removeActionForKey("repeatAction")
  
              self.jump(self.force)
  
              self.force = Constants.minimumJumpForce
  
              self.pressed = false
          }
  
  
          override func update(currentTime: NSTimeInterval) {
  
  
              debugLabel.text = "DEBUG: onTheGround : \(isCharacterOnGround), force \(force)"
  
  
  
              if(character.position.x <= character.size.width/2.0 + 5.0 && character.physicsBody?.velocity.dx < 0.0 ){
  
                 character.physicsBody?.applyForce(CGVectorMake(Constants.characterSideSpeed, 0.0))
  
  
              }else if((character.position.x >= self.frame.size.width - character.size.width/2.0 - 5.0) && character.physicsBody?.velocity.dx >= 0.0){
  
                  character.physicsBody?.applyForce(CGVectorMake(-Constants.characterSideSpeed, 0.0))
  
              }else if(character.physicsBody?.velocity.dx > 0.0){
  
                 character.physicsBody?.applyForce(CGVectorMake(Constants.characterSideSpeed, 0.0))
  
              }else{
  
                  character.physicsBody?.applyForce(CGVectorMake(-Constants.characterSideSpeed, 0.0))
  
              }
  
  
          }
  
  
      func didBeginContact(contact: SKPhysicsContact) {
  
          var firstBody, secondBody: SKPhysicsBody
  
          if contact.bodyA.categoryBitMask < contact.bodyB.categoryBitMask {
              firstBody = contact.bodyA
              secondBody = contact.bodyB
          } else {
              firstBody = contact.bodyB
              secondBody = contact.bodyA
          }
  
  
          if ((firstBody.categoryBitMask & CharacterCategory) != 0 &&
              (secondBody.categoryBitMask & PlatformCategory != 0)) {
  
              let platform = secondBody.node as SKSpriteNode
              //  platform.color = UIColor.redColor()
              let platformSurfaceYPos = platform.position.y + platform.size.height/2.0
  
              let player = contact.bodyB.node as SKSpriteNode
              let playerLegsYPos = player.position.y - player.size.height/2.0
  
  
  
              if((platformSurfaceYPos <= playerLegsYPos)  ){
  
                  character.physicsBody?.collisionBitMask = PlatformCategory | WallCategory
  
  
  
                  self.isCharacterOnGround = true
  
                  if(self.pressed){
  
  
                      var characterDx = character.physicsBody?.velocity.dx
  
                      character.physicsBody?.velocity = CGVector(dx: characterDx!, dy: 0.0)
  
                      self.jump(Constants.maximumJumpForce)
                  }
  
              }
  
  
          }
  
  
  
      }
  
      func didEndContact(contact: SKPhysicsContact) {
  
          var firstBody, secondBody: SKPhysicsBody
  
          if contact.bodyA.categoryBitMask < contact.bodyB.categoryBitMask {
              firstBody = contact.bodyA
              secondBody = contact.bodyB
          } else {
              firstBody = contact.bodyB
              secondBody = contact.bodyA
          }
  
          if ((firstBody.categoryBitMask & CharacterCategory) != 0 &&
              (secondBody.categoryBitMask & PlatformCategory != 0)) {
  
  
              let platform = secondBody.node as SKSpriteNode
              let platformSurfaceYPos = platform.position.y + platform.size.height/2.0
  
              let player = contact.bodyB.node as SKSpriteNode
              let playerLegsYPos = player.position.y - player.size.height/2.0
  
  
  
              if((platformSurfaceYPos <= playerLegsYPos) && (character.physicsBody?.velocity.dy > 0.0)){
  
                  character.physicsBody?.collisionBitMask = WallCategory
  
                  self.isCharacterOnGround = false
  
              }
  
          }
  
      }
  
  }
  

Note that this is simple example, and in real application you will probably have to handle states like isOnTheGround in a different way. Right now, to determine if character is on the ground you just set isOnTheGround = true when character make a contact with platform, and set it to false in didEndContact...But there are situations when character can be in contact with platform while in the air (eg. side contact)...

EDIT:

I changed the code to let the player jump while pressed. Here is the result:

Important:

Actual platform implementation and contact handling is up to you and this is not tested. The only purpose of this example is to show you how to jump while pressed. Currently, physicsWorld.speed is set to 0.5 to make animation slower because its easier to debug like that, but you can change this to default value (1.0).

So, as you can see from the image, while player is on the first platform some small jumps are presented (by simple tapping, or short pressing). Then (player is still on first platform) long press has been made, and player has jumped on second platform. After that, another long press is done, but this time without releasing, and player starts jumping from one platform to another using maximum force.

This needs a lot of tweaking and proper platform & contact detection, but it can give you an idea about how to implement jumping you asked about.