How can I detect touch in cocos2d ?

Question

I am developing a 2d game for iPhone by using cocos2d.

I use many small sprite (image) in my game. I want to touch two similar types of sprite(image) and then both sprite(image) will be hidden.

How can I detect touch in a specific sprite(image) ?

Answer 1

In your layer that contains your sprite, you need to say:

self.isTouchEnabled = YES;

then you can use the same events that you would use in a UIView, but they're named a little differently:

- (void)ccTouchesBegan:(NSSet*)touches withEvent:(UIEvent*)event
{
   UITouch* touch = [touches anyObject];
  //in your touchesEnded event, you would want to see if you touched
  //down and then up inside the same place, and do your logic there.
}

Answer 2

Following Jonas's instructions, and adding onto it a bit more ...

- (void)ccTouchesBegan:(NSSet*)touches withEvent:(UIEvent*)event
{
   UITouch* touch = [touches anyObject];
   CGPoint location = [[[Director sharedDirector] convertCoordinate: touch.location];
   CGRect particularSpriteRect = CGMakeRect(particularSprite.position.x, particularSprite.position.y, particularSprite.contentSize.width, particularSprite.contentSize.height);
   if(CGRectContainsPoint(particularSpriteRect, location)) {
     // particularSprite touched
     return kEventHandled;
   }
}

You may need to adjust the x/y a little to account for the 'centered positioning' in Cocos

Answer 3

@Genericrich: CGRectContainsPoint works in CocosLand because of the call 2 lines above:

[[Director sharedDirector] convertCoordinate:]

The Cocos2D objects will be using the OpenGL coordinate system, where 0,0 is the lower left, and UIKit coordinates (like where the touch happened) have 0,0 is upper left. convertCoordinate: is making the flip from UIKit to OpenGL for you.

Answer 4

@david, your code has some typos for cocos 0.7.3 and 2.2.1, specifically CGRectMake instead of CGMakeRect and [touch location] is now [touch locationInView:touch.view].

here's what I did:

- (BOOL)ccTouchesEnded:(NSSet *)touches withEvent:(UIEvent *)event {
    UITouch * touch = [touches anyObject];

    CGPoint location = [[Director sharedDirector] convertCoordinate: [touch locationInView:touch.view]];
    CGRect myRect = CGRectMake(sprite.position.x, sprite.position.y, sprite.contentSize.width, sprite.contentSize.height);


    if(CGRectContainsPoint(myRect, location)) {
     // particularSprite touched
     return kEventHandled;
    }
}

Answer 5

Here's how it worked for me... Where spriteSize is obviously the sprite's size... :P

- (BOOL)ccTouchesEnded:(NSSet *)touches withEvent:(UIEvent *)event {
    UITouch * touch = [touches anyObject];

    CGPoint location = [[Director sharedDirector] convertCoordinate: [touch locationInView:touch.view]];
    CGRect myRect = CGRectMake(sprite.position.x-spriteSize/2, sprite.position.y-spriteSize/2, spriteSize, spriteSize);


    if(CGRectContainsPoint(myRect, location)) {
        // particularSprite touched
        return kEventHandled;
    }
}

Answer 6

I have been trying to figure out how to get hold of touches of a given sprite and found this thread.

Is this the correct way to detect which sprite was touched? This seems a rather odd way to do it compared to the usual sub-class way in obj-c?

So all the touch detection code is in the layer class?

Thanks for pointers