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How do you implement a touch hash code and reference it later? I have read about a "hash" code, but I don't understand how to use it. I want to know when two of my Sprites are touched at the same time, like as if pressing a chord on two keys of a piano.

Here is an example of what I have for my ccTouchesBegan:

- (void) ccTouchesBegan:(NSSet*)touches withEvent:(UIEvent*)event {

  NSSet *allTouches = [event allTouches];
  int validTouchCount = 0;
  for (UITouch* touch in allTouches) {

    BOOL touchIsValid = FALSE;

    CGPoint location = [touch locationInView: [touch view]];
    CGPoint convertedLocation = [[CCDirector sharedDirector] convertToGL:location];

    if (CGRectContainsPoint(_fourButtonsRect, convertedLocation)) {
        NSLog(@"Touch is within four buttons");
        touchIsValid = TRUE;
    }


    _playerDidAction = 0;
    NSLog(@"before the loop");
    if (touchIsValid) {

        validTouchCount++;
        NSLog(@"Within ValidTouches loop");
        CGPoint validLocation = [touch locationInView: [touch view]];
        CGPoint convertedValidLocation = [[CCDirector sharedDirector] convertToGL:validLocation];

        if (CGRectContainsPoint(_redButtonSprite.boundingBox, convertedValidLocation)) {
            _redButtonStatus = TRUE;
            [_redButtonSprite setTexture:_redButtonLit];
            if (validTouchCount == 1) {
                _playerDidAction = 1;
            }
        }
            else if (CGRectContainsPoint(_blueButtonSprite.boundingBox, convertedValidLocation)) {  
                _blueButtonStatus = TRUE;
                [_blueButtonSprite setTexture:_blueButtonLit];
                if (validTouchCount == 1) {
                    _playerDidAction = 2;
                }
            }
                else if (CGRectContainsPoint(_greenButtonSprite.boundingBox, convertedValidLocation)) { 
                    _greenButtonStatus = TRUE;
                    [_greenButtonSprite setTexture:_greenButtonLit];
                    if (validTouchCount == 1) {
                        _playerDidAction = 3;
                    }
                }
                    else if (CGRectContainsPoint(_yellowButtonSprite.boundingBox, convertedValidLocation)) {    
                        _yellowButtonStatus = TRUE;
                        [_yellowButtonSprite setTexture:_yellowButtonLit];
                        if (validTouchCount == 1) {
                            _playerDidAction = 4;
                        }
                    }

        if (validTouchCount > 1) {

            if (_redButtonStatus && _blueButtonStatus) {
                _comboRB = TRUE;
                _playerDidAction = 5;
            }
                else if (_redButtonStatus && _greenButtonStatus) {
                    _comboRG = TRUE;
                    _playerDidAction = 6;
                }
                    else if (_redButtonStatus && _yellowButtonStatus) {
                        _comboRY = TRUE;
                        _playerDidAction = 7;
                    }
                        else if (_blueButtonStatus && _greenButtonStatus) {
                            _comboBG = TRUE;
                            _playerDidAction = 8;
                        }
                            else if (_blueButtonStatus && _yellowButtonStatus) {
                                _comboBY = TRUE;
                                _playerDidAction = 9;
                            }
                                else if (_greenButtonStatus && _yellowButtonStatus) {
                                    _comboGY = TRUE;
                                    _playerDidAction = 10;
                                }

        }
    }
  }
}

And here is the beginning of my ccTouchesEnded:

- (void)ccTouchesEnded:(NSSet*)touches withEvent:(UIEvent*)event {

    for (UITouch *touch in touches) {


        CGPoint location = [touch locationInView: [touch view]];
        CGPoint convertedLocation = [[CCDirector sharedDirector] convertToGL:location];     
        if (CGRectContainsPoint(_redButtonSprite.boundingBox, convertedLocation)) { 
            _redButtonStatus = FALSE;
            [_redButtonSprite setTexture:_redButtonNormal];
        }
        if (CGRectContainsPoint(_blueButtonSprite.boundingBox, convertedLocation)) {    
            _blueButtonStatus = FALSE;
            [_blueButtonSprite setTexture:_blueButtonNormal];
        }
        if (CGRectContainsPoint(_greenButtonSprite.boundingBox, convertedLocation)) {   
            _greenButtonStatus = FALSE;
            [_greenButtonSprite setTexture:_greenButtonNormal];
        }
        if (CGRectContainsPoint(_yellowButtonSprite.boundingBox, convertedLocation)) {  
            _yellowButtonStatus = FALSE;
            [_yellowButtonSprite setTexture:_yellowButtonNormal];
        }


    }
}

Could you give me an example of how I would code the capture of the hash code in the touchesBegan and then reference the hash code in the touchesEnded? I have been struggling and can't get the hash code to work - just not understanding how the hash code can be used to reference a touch later. I guess what I'm trying to make would be called a hash tracker?

I am sure there is a much less convoluted way to do it using the hash codes and less state variables. I haven't fleshed out the ccTouchesEnded method with the other state variable effects because I was hoping to find a simpler way (I know I still need to make the ccTouchesMoved and Canceled methods too).

Any advise would be very appreciated as I am stuck! B)

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3 Answers

To reduce the amount of if statements you have you need to make your solution data-driven instead of manually adding logic for each UI component that needs to interact.

You could do this by storing your buttons data (such as each buttons bounding box and state) in an array of structs or a NSArray (or NSMutableArray) of classes. Then when you receive a touch you just need to iterate over the list to see if any touches are inside the bounding box, if it is then update that objects texture.

To keep track of touches across their lifetime I use a single NSMutableDictionary with the touches pointer as its key and a custom class as its value. This allows me to store information per touch (such as if I've already handled it) and react to touches that are held and not moving.

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I couldn't figure out how to implement it your way so I have posted my answer. If you could elaborate on your answer referencing my answer it would be greatly appreciated. –  Mark7777G Jan 22 '11 at 23:27
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i'm guessing that you are tiring of typing all those if statements.

maybe a simple addition to what you already seem to have going on is to add a setStatus method to your sprite class. also make the sprite object track what its state TRUE and state FALSE textures are. then you can just iterate thru the touches and check all your objects in a loop with a single setState call.

unless you have a zillion sprites it will probably be no slower than what you have going on now.

im not sure at all what you mean by hash codes in this instance?

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Yes tired of the if statements! I was actually trying to get the gyst of it working and then refine it into something prettier as you suggested. I'm working on setting up the sprite sub-class now, we will see how it works. I will add the setStatus method you suggested. The hash code I'm refering to supposedly would allow me to ensure I reference the same touch in all the touch methods (cctouchesBegan/Moved/Ended/Canceled) by calling the [touch hash]. I just don't know the proper way to store the hash (in the ccTouchesBegan) and how to reference it later in the other methods. –  Mark7777G Nov 9 '10 at 3:25
    
oh, i see what you mean now. i think you'll find that its not really necessary to associate each touch that way, in fact i think it may be possible to have some touches start and you never get a cancel or end for them. but if you want to do it, just create a map object in your class and then you can add touches to it as you suggest. the trick would be generating the key, and im not sure the info you get about the touch events has any state in it that would let you pull that off. –  Dr. McKay Nov 10 '10 at 0:59
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up vote 0 down vote accepted

Here is how I implemented this in case anyone else is trying to do this (I have limited it to 2-button combos but I could easily extend the logic to 3 & 4-button combos as well). I chose to handle each touch individually using the ccTouchBegan/Ended/Moved instead of using the ccTouchesBegan/Ended/Moved because I just couldn't get it to work with the hash code. Any alternative ideas would be welcome.

spuButton.h (a CCSprite Subclass)

#import <Foundation/Foundation.h>
#import "cocos2d.h"

typedef enum tagButtonState {
 kButtonStatePressed,
 kButtonStateNotPressed
} ButtonState;

typedef enum tagButtonStatus {
 kButtonStatusEnabled,
 kButtonStatusDisabled
} ButtonStatus;

@interface spuButton : CCSprite <CCTargetedTouchDelegate> {
@private
 ButtonState buttonState;
 CCTexture2D *buttonNormal;
 CCTexture2D *buttonLit;
 ButtonStatus buttonStatus; 
}

@property(nonatomic, readonly) CGRect rect;

+ (id)spuButtonWithTexture:(CCTexture2D *)normalTexture;

- (void)setNormalTexture:(CCTexture2D *)normalTexture;
- (void)setLitTexture:(CCTexture2D *)litTexture;
- (BOOL)isPressed;
- (BOOL)isNotPressed;
- (void)makeDisabled;
- (void)makeEnabled;
- (BOOL)isEnabled;
- (BOOL)isDisabled;
- (void)makeLit;
- (void)makeNormal;
- (void)dealloc;

@end

spuButton.m

#import "spuButton.h"
#import "cocos2d.h"

@implementation spuButton

- (CGRect)rect {
 CGSize s = [self.texture contentSize];
 return CGRectMake(-s.width / 2, -s.height / 2, s.width, s.height);
}

+ (id)spuButtonWithTexture:(CCTexture2D *)normalTexture {
 return [[[self alloc] initWithTexture:normalTexture] autorelease];
}

- (void)setNormalTexture:(CCTexture2D *)normalTexture {
 buttonNormal = normalTexture;
}
- (void)setLitTexture:(CCTexture2D *)litTexture {
 buttonLit = litTexture;
}

- (BOOL)isPressed {
 if (buttonState== kButtonStateNotPressed) return NO;
 if (buttonState== kButtonStatePressed) return YES;
 return NO;
}

- (BOOL)isNotPressed {
 if (buttonState== kButtonStateNotPressed) return YES;
 if (buttonState== kButtonStatePressed) return NO;
 return YES;
}

- (void)makeDisabled {
 buttonStatus = kButtonStatusDisabled;
 buttonState= kButtonStateNotPressed;
 [self makeNormal];
}
- (void)makeEnabled {
 buttonStatus = kButtonStatusEnabled;
 buttonState= kButtonStateNotPressed;
 [self makeNormal];
}

- (BOOL)isEnabled {
 if (buttonStatus== kButtonStatusDisabled) return NO;
 if (buttonStatus== kButtonStatusEnabled) return YES;
 return NO;
}

- (BOOL)isDisabled {
 if (buttonStatus== kButtonStatusEnabled) return NO;
 if (buttonStatus== kButtonStatusDisabled) return YES;
 return YES;
}

- (void)makeLit {
 [self setTexture:buttonLit];
}

- (void)makeNormal {
 [self setTexture:buttonNormal];
}

- (id)initWithTexture:(CCTexture2D *)aTexture {
 if ((self = [super initWithTexture:aTexture]) ) {  
  buttonState = kButtonStateNotPressed;
  buttonStatus = kButtonStatusEnabled;
 }
 return self;
}

- (void)onEnter {
 if (buttonStatus == kButtonStatusDisabled) return;
 [[CCTouchDispatcher sharedDispatcher] addTargetedDelegate:self priority:0 swallowsTouches:NO];
 [super onEnter];
}

- (void)onExit {
 if (buttonStatus == kButtonStatusDisabled) return;
 [[CCTouchDispatcher sharedDispatcher] removeDelegate:self];
 [super onExit];
} 

- (BOOL)containsTouchLocation:(UITouch *)touch {
 return CGRectContainsPoint(self.rect, [self convertTouchToNodeSpaceAR:touch]);
}

- (BOOL)ccTouchBegan:(UITouch *)touch withEvent:(UIEvent *)event {
 if (buttonStatus == kButtonStatusDisabled) return NO;
 if (buttonState== kButtonStatePressed) return NO;
 if ( ![self containsTouchLocation:touch] ) return NO;

 buttonState= kButtonStatePressed;
 [self makeLit];

 return YES;
}

- (void)ccTouchMoved:(UITouch *)touch withEvent:(UIEvent *)event {
 // If it weren't for the TouchDispatcher, you would need to keep a reference
 // to the touch from touchBegan and check that the current touch is the same
 // as that one.
 // Actually, it would be even more complicated since in the Cocos dispatcher
 // you get NSSets instead of 1 UITouch, so you'd need to loop through the set
 // in each touchXXX method.

 if (buttonStatus == kButtonStatusDisabled) return;
 if ([self containsTouchLocation:touch]) return;

 buttonState= kButtonStateNotPressed;
 [self makeNormal];
}

- (void)ccTouchEnded:(UITouch *)touch withEvent:(UIEvent *)event {
 if (buttonStatus == kButtonStatusDisabled) return;

 buttonState= kButtonStateNotPressed;
 [self makeNormal];
}

- (void)dealloc {
 [buttonNormal release];
 [buttonLit release];
 [super dealloc];
}

@end

HelloWorldScene.m (Just my tick: method to keep my other functions from confusing the example)

-(void)tick:(ccTime)dt {
 if ([[_otherControlsArray objectAtIndex:0] wasPressed]) {
  [[_otherControlsArray objectAtIndex:0] setWasPressed:NO];
  [self removeChild:[_otherControlsArray objectAtIndex:0] cleanup:YES];
  [self addChild:[_otherControlsArray objectAtIndex:1]];
  NSLog(@"Play");

  _gameHasNotBeenPlayedYet = NO;
  Snarfle_s_PowerUPAppDelegate *delegate = [[UIApplication sharedApplication] delegate];
  [delegate makeNotPaused];
  [self gameLogic];
 }

 if (_gameHasNotBeenPlayedYet) {
  return;
 }

 if (_buttonsPressedAndReleased > 0) {  //respond to button(s) released and reset
  NSLog(@"Buttons Pressed and Released-->%d",_buttonsPressedAndReleased);
  if ([self checkButtons:_buttonsPressedAndReleased]);
  _buttonsPressed = 0;
  _buttonsPressedAndReleased = 0;

  return;
 }
 if (_buttonsPressed <= 4) { // two buttons have not already been pressed
  for (spuButton *aButton in _fourButtonsArray) {
   if ([aButton isNotPressed]) continue; //this button is not pressed
   if (_buttonsPressed == 0) { //this button is pressed and no other buttons have been pressed
    _buttonsPressed = aButton.tag;
    continue;
   }
   //this button is pressed while another has been pressed
   //figure out which two buttons have been pressed
   if (_buttonsPressed == 1) {  //red plus another
    switch (aButton.tag) {
     case 2:   //blue
      _buttonsPressed = 5;
      [[_fourButtonsArray objectAtIndex:2] makeDisabled];
      [[_fourButtonsArray objectAtIndex:3] makeDisabled];
      break;
     case 3:  //green
      _buttonsPressed = 6;
      [[_fourButtonsArray objectAtIndex:1] makeDisabled];
      [[_fourButtonsArray objectAtIndex:3] makeDisabled];
      break;
     case 4:  //yellow
      _buttonsPressed = 7;
      [[_fourButtonsArray objectAtIndex:1] makeDisabled];
      [[_fourButtonsArray objectAtIndex:2] makeDisabled];
      break;
     default:
      _buttonsPressed = 1;
      break;
    }
   }
   if (_buttonsPressed == 2) {  //blue plus another
    switch (aButton.tag) {
     case 1:   //red
      _buttonsPressed = 5;
      [[_fourButtonsArray objectAtIndex:2] makeDisabled];
      [[_fourButtonsArray objectAtIndex:3] makeDisabled];
      break;
     case 3:  //green
      _buttonsPressed = 8;
      [[_fourButtonsArray objectAtIndex:0] makeDisabled];
      [[_fourButtonsArray objectAtIndex:3] makeDisabled];
      break;
     case 4:  //yellow
      _buttonsPressed = 9;
      [[_fourButtonsArray objectAtIndex:0] makeDisabled];
      [[_fourButtonsArray objectAtIndex:2] makeDisabled];
      break;
     default:
      _buttonsPressed = 2;
      break;
    }
   }
   if (_buttonsPressed == 3) {  //green plus another
    switch (aButton.tag) {
     case 1:   //red
      _buttonsPressed = 6;
      [[_fourButtonsArray objectAtIndex:1] makeDisabled];
      [[_fourButtonsArray objectAtIndex:3] makeDisabled];
      break;
     case 2:  //blue
      _buttonsPressed = 8;
      [[_fourButtonsArray objectAtIndex:0] makeDisabled];
      [[_fourButtonsArray objectAtIndex:3] makeDisabled];
      break;
     case 4:  //yellow
      _buttonsPressed = 10;
      [[_fourButtonsArray objectAtIndex:0] makeDisabled];
      [[_fourButtonsArray objectAtIndex:1] makeDisabled];
      break;
     default:
      _buttonsPressed = 3;
      break;
    }
   }
   if (_buttonsPressed == 4) {  //yellow plus another
    switch (aButton.tag) {
     case 1:   //red
      _buttonsPressed = 7;
      [[_fourButtonsArray objectAtIndex:1] makeDisabled];
      [[_fourButtonsArray objectAtIndex:2] makeDisabled];
      break;
     case 2:  //blue
      _buttonsPressed = 9;
      [[_fourButtonsArray objectAtIndex:0] makeDisabled];
      [[_fourButtonsArray objectAtIndex:2] makeDisabled];
      break;
     case 3:  //green
      _buttonsPressed = 10;
      [[_fourButtonsArray objectAtIndex:0] makeDisabled];
      [[_fourButtonsArray objectAtIndex:1] makeDisabled];
      break;
     default:
      _buttonsPressed = 4;
      break;
    }
   }
   if (_buttonsPressed > 4) break;  //more than one has been pressed and identified
  }
 }
 //now we know what buttons have been pressed now check to see if they have been released
 //if more than one has been pressed disable the other two
 //also if more than one has been pressed and one of them gets released disable the released one but keep it lit
 switch (_buttonsPressed) {
  case 1:  //red
   if ([[_fourButtonsArray objectAtIndex:0] isNotPressed]) _buttonsPressedAndReleased = 1;
   break;
  case 2:  //blue
   if ([[_fourButtonsArray objectAtIndex:1] isNotPressed]) _buttonsPressedAndReleased = 2;
   break;
  case 3:  //green
   if ([[_fourButtonsArray objectAtIndex:2] isNotPressed]) _buttonsPressedAndReleased = 3;
   break;
  case 4:  //yellow
   if ([[_fourButtonsArray objectAtIndex:3] isNotPressed]) _buttonsPressedAndReleased = 4;
   break;
  case 5:  //red & blue
   if (([[_fourButtonsArray objectAtIndex:0] isNotPressed]) && ([[_fourButtonsArray objectAtIndex:1] isNotPressed])) _buttonsPressedAndReleased = 5;
   else {
    if ([[_fourButtonsArray objectAtIndex:0] isNotPressed]) {
     [[_fourButtonsArray objectAtIndex:0] makeDisabled];
     [[_fourButtonsArray objectAtIndex:0] makeLit];
    }
    if ([[_fourButtonsArray objectAtIndex:1] isNotPressed]) {
     [[_fourButtonsArray objectAtIndex:1] makeDisabled];
     [[_fourButtonsArray objectAtIndex:1] makeLit];
    }
   }
   break;
  case 6:  //red & green
   if (([[_fourButtonsArray objectAtIndex:0] isNotPressed]) && ([[_fourButtonsArray objectAtIndex:2] isNotPressed])) _buttonsPressedAndReleased = 6;
   else {
    if ([[_fourButtonsArray objectAtIndex:0] isNotPressed]) {
     [[_fourButtonsArray objectAtIndex:0] makeDisabled];
     [[_fourButtonsArray objectAtIndex:0] makeLit];
    }
    if ([[_fourButtonsArray objectAtIndex:2] isNotPressed]) {
     [[_fourButtonsArray objectAtIndex:2] makeDisabled];
     [[_fourButtonsArray objectAtIndex:2] makeLit];
    }
   }
   break;
  case 7:  //red & yellow
   if (([[_fourButtonsArray objectAtIndex:0] isNotPressed]) && ([[_fourButtonsArray objectAtIndex:3] isNotPressed])) _buttonsPressedAndReleased = 7;
   else {
    if ([[_fourButtonsArray objectAtIndex:0] isNotPressed]) {
     [[_fourButtonsArray objectAtIndex:0] makeDisabled];
     [[_fourButtonsArray objectAtIndex:0] makeLit];
    }
    if ([[_fourButtonsArray objectAtIndex:3] isNotPressed]) {
     [[_fourButtonsArray objectAtIndex:3] makeDisabled];
     [[_fourButtonsArray objectAtIndex:3] makeLit];
    }
   }
   break;
  case 8:  //blue & green
   if (([[_fourButtonsArray objectAtIndex:1] isNotPressed]) && ([[_fourButtonsArray objectAtIndex:2] isNotPressed])) _buttonsPressedAndReleased = 8;
   else {
    if ([[_fourButtonsArray objectAtIndex:1] isNotPressed]) {
     [[_fourButtonsArray objectAtIndex:1] makeDisabled];
     [[_fourButtonsArray objectAtIndex:1] makeLit];
    }
    if ([[_fourButtonsArray objectAtIndex:2] isNotPressed]) {
     [[_fourButtonsArray objectAtIndex:2] makeDisabled];
     [[_fourButtonsArray objectAtIndex:2] makeLit];
    }
   }
   break;
  case 9:  //blue & yellow
   if (([[_fourButtonsArray objectAtIndex:1] isNotPressed]) && ([[_fourButtonsArray objectAtIndex:3] isNotPressed])) _buttonsPressedAndReleased = 9;
   else {
    if ([[_fourButtonsArray objectAtIndex:1] isNotPressed]) {
     [[_fourButtonsArray objectAtIndex:1] makeDisabled];
     [[_fourButtonsArray objectAtIndex:1] makeLit];
    }
    if ([[_fourButtonsArray objectAtIndex:3] isNotPressed]) {
     [[_fourButtonsArray objectAtIndex:3] makeDisabled];
     [[_fourButtonsArray objectAtIndex:3] makeLit];
    }
   }
   break;
  case 10:  //green & yellow
   if (([[_fourButtonsArray objectAtIndex:2] isNotPressed]) && ([[_fourButtonsArray objectAtIndex:3] isNotPressed])) _buttonsPressedAndReleased = 10;
   else {
    if ([[_fourButtonsArray objectAtIndex:2] isNotPressed]) {
     [[_fourButtonsArray objectAtIndex:2] makeDisabled];
     [[_fourButtonsArray objectAtIndex:2] makeLit];
    }
    if ([[_fourButtonsArray objectAtIndex:3] isNotPressed]) {
     [[_fourButtonsArray objectAtIndex:3] makeDisabled];
     [[_fourButtonsArray objectAtIndex:3] makeLit];
    }
   }
   break;
  default:
   _buttonsPressedAndReleased = 0;
   break;
 }
}
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