Keyboard input for use with SpriteKit or SceneKit

Keyboard.swift

//
//  Keyboard.swift
//
//  Created by Bojan Percevic on 5/21/15.
//  Copyright (c) 2015 Bojan Percevic. All rights reserved.
//

import AppKit

enum Key: CUnsignedShort {
   case A = 0x00 // = 0
   case S = 0x01
   case D = 0x02
   case F = 0x03
   case H = 0x04
   case G = 0x05
   case Z = 0x06
   case X = 0x07
   case C = 0x08
   case V = 0x09
   case B = 0x0B
   case Q = 0x0C
   case W = 0x0D
   case E = 0x0E
   case R = 0x0F
   case Y = 0x10
   case T = 0x11
   case One = 0x12
   case Two = 0x13
   case Three = 0x14
   case Four = 0x15
   case Six = 0x16
   case Five = 0x17
   case Equals = 0x18
   case Nine = 0x19
   case Seven = 0x1A
   case Minus = 0x1B
   case Eight = 0x1C
   case Zero = 0x1D
   case RightBracket = 0x1E
   case O = 0x1F
   case U = 0x20
   case LeftBracket = 0x21
   case I = 0x22
   case P = 0x23
   case Return = 0x24
   case L = 0x25
   case J = 0x26
   case Quote = 0x27
   case K = 0x28
   case Semicolon = 0x29
   case Backslash = 0x2A
   case Comma = 0x2B
   case Slash = 0x2C
   case N = 0x2D
   case M = 0x2E
   case Period = 0x2F
   case Tab = 0x30
   case Space = 0x31
   case Grave = 0x32
   case Delete = 0x33

   case Escape = 0x35

   case Command = 0x37
   case LeftShift = 0x38
   case CapsLock = 0x39
   case LeftOption = 0x3A
   case LeftControl = 0x3B
   case RightShift = 0x3C
   case RightOption = 0x3D
   case RightControl = 0x3E
   case Function = 0x3F
   case F17 = 0x40
   case KeypadDecimal = 0x41

   case KeypadMultiply = 0x43

   case KeypadPlus = 0x45

   case KeypadClear = 0x47
   case VolumeUp = 0x48
   case VolumeDown = 0x49
   case Mute = 0x4A
   case KeypadDivide = 0x4B
   case KeypadEnter = 0x4C

   case KeypadMinus = 0x4E
   case F18 = 0x4F
   case F19 = 0x50
   case KeypadEquals = 0x51
   case KeypadZero = 0x52
   case KeypadOne = 0x53
   case KeypadTwo = 0x54
   case KeypadThree = 0x55
   case KeypadFour = 0x56
   case KeypadFive = 0x57
   case KeypadSix = 0x58
   case KeypadSeven = 0x59
   case F20 = 0x5A
   case KeypadEight = 0x5B
   case KeypadNine = 0x5C

   case F5 = 0x60
   case F6 = 0x61
   case F7 = 0x62
   case F3 = 0x63
   case F8 = 0x64
   case F9 = 0x65
   case F11 = 0x67
   case F13 = 0x69
   case F16 = 0x6A
   case F14 = 0x6B
   case F10 = 0x6D
   case F12 = 0x6F
   case F15 = 0x71
   case Help = 0x72
   case Home = 0x73
   case PageUp = 0x74
   case ForwardDelete = 0x75
   case F4 = 0x76
   case End = 0x77
   case F2 = 0x78
   case PageDown = 0x79
   case F1 = 0x7A
   case Left = 0x7B
   case Right = 0x7C
   case Down = 0x7D
   case Up = 0x7E // = 126
   
   case Count = 0x7F
}

struct KeyState {
   var keys = [Bool](count: Int(Key.Count.rawValue), repeatedValue: false)
}

class Keyboard {
   
   static let sharedKeyboard = Keyboard()
   
   var prev: KeyState
   var curr: KeyState
   
   init() {
      prev = KeyState()
      curr = KeyState()
   }
   
   func handleKey(event: NSEvent, isDown: Bool) {
      if (isDown) {
         curr.keys[Int(event.keyCode)] = true
      } else {
         curr.keys[Int(event.keyCode)] = false
      }
   }
   
   func justPressed(keys: Key...) -> Bool {
      for key in keys {
         if (curr.keys[Int(key.rawValue)] == true && prev.keys[Int(key.rawValue)] == false) {
            return true
         }
      }
      return false
   }
   
   func justReleased(keys: Key...) -> Bool {
      for key in keys {
         if (prev.keys[Int(key.rawValue)] == true && curr.keys[Int(key.rawValue)] == false) {
            return true
         }
      }
      return false
   }
   
   func pressed(keys: Key...) -> Bool {
      for key in keys {
         if (prev.keys[Int(key.rawValue)] == true && curr.keys[Int(key.rawValue)] == true) {
            return true
         }
      }
      return false
   }
   
   func update() {
      prev = curr
   }
   
}

Can be used like this

class Scene: SKScene {
  override func update(currentTime: NSTimeInterval) {
    super.update(currentTime)

    if (Keyboard.sharedKeyboard.justPressed(KeyCode.Space)) {
      // single key
    } else if (Keyboard.sharedKeyboard.pressed(KeyCode.Space, KeyCode.Return)) {
      // two keys
    } else if (Keyboard.sharedKeyboard.justReleased(KeyCode.Space, KeyCode.W, KeyCode.T, KeyCode.LeftShift)) {
      // many keys
    }
  }

  override func didFinishUpdate() {
    Keyboard.sharedKeyboard.update()
  }

  override func keyUp(theEvent: NSEvent) {
    Keyboard.sharedKeyboard.handleKey(theEvent, isDown: false)
  }

  override func keyDown(theEvent: NSEvent) {
    Keyboard.sharedKeyboard.handleKey(theEvent, isDown: true)
  }
}

of course you can also create an instance of Keyboard.

Hi.
First of all let me thank you for this awesome tutorial/sample code. It really helped me out!
I only have one problem: i can't get it to read three or more keypresses. When i have one key pressed down and i press another one it works fine, but when I have two keys pressed down and I press a third one, the third pressed key doesn't register. If you could offer some advice on how to fix this, I shall be forever grateful. Thx