Simultaneous Sprite Touch Detection - iPhone & cocos2d

Question

I am writing an app for the iPhone using cocos2d where I have 4 Sprites that are buttons. I figured I would implement the button functionality by using 2 sprites with different .png files representing the pressed/unpressed states. I thought this would be better than using an animation. In addition to detecting when the buttons are pressed and released I need to detect when a two-button combination press/release occurs (like a chord). I might even carry this forward to 3 and 4 button combos. And one more feature I would like to implement would be detecting if a flick originated from within a button and respond with another action sequence.

What would be an optimal approach for this? Would I use a bounding rect/or sprite for the four buttons (they are in a square formation) and swallow touches? Then would I use the smaller sprite rects to determine which one(s) the touch(es) happened on? Or would I have the individual sprite rects do the detection and then have them check to see if the other buttons are also pressed and then released at the same time? Would I use a Bool state variable for either of these ways?

I had it all working great using CCMenu and CCMenuitem, by making one Menu/Menu-item for each button sprite; however, I could not figure out how to detect if a menu-item from one menu was pressed and released at the same time a menu-item from a different menu was pressed and released. I used separate menus because if I used the same menu with multiple menu-items then only one could be pressed at a time. I say it was working fine meaning it worked with single and multiple presses but it would treat multiples as two successive presses instead of a simultaneous press. IE: a single press resulted in running a single action sequence(as intended), and a simultaneous press combination resulted in running individual button action sequences for each button as if I had pressed them each separately(I want it to run one action sequence specific to that button combination). This is why I decided it might be better to try to implement my own button system instead of using the CCMenu system. Am I right in moving away from CCMenu?

Sorry for the long description, but it did say to be specific. B)

Any insight as to how anyone else implemented or would implement this would be greatly appreciated!

Answer 1

Here is how I implemented this in case anyone else is trying to do this.

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;
    }
}