CODEWITHSUNDEEP
ioscocos2d-iphonetouchesbegantouchesmoved
quantumpotato
quantumpotato

Reputation: 9767

Eating a touch that began in one layer and preventing ccMoved calls (or touchesMoved)

Using Cocos2D to create a shoot-em-up bullet hell style game. One finger drags to move the ship and there are fire layers in the corner.

From my main layer, I detect ccTouchesBegan, ccTouchesMoved and ccTouchesEnded. I pass a CGPoint into my logic controller.

If a touch down point is inside one of the 2 "fire button" layers, then I trigger a fire event. Otherwise I set a new location for the player ship. When a touch moves outside of the fire layer areas, I set a new location for the player ship.

Problem: Dragging a finger from within the fire layer into non-fire layer space causes the ship to jump to that point because of the "touch moves set player location" rule.

How can I architect this better?

Perhaps I need an array of "touch objects", and nullify them when crossing the boundary of the fire layer. I feel like I am missing some important concept about touch handling here that, if understood, would give the control I want without having to hack a "touch object" class that compares where you're tapping to an array of locations.

Please advise. Thanks!

(Yes, I saw: How do I limit touch handling to one layer when layers overlap? . That does not answer my question. The rectContainsPoint is how I determine if a touch is within or out of a fire layer).

Upvotes: 1

Views: 287

Answers (1)

jrturton
jrturton

Reputation: 119242

Can you set a flag (a BOOL ivar) in touchesBegan to indicate that the touch began in the fire area, and if this flag is set, dont move the ship? You would re-set it at touchesEnded.

That sounds too simple, so I'm probably missing something.

I was indeed. To handle multi touch you would need an array as you guess in the question - on touches began, if the touch was in the fire zone, add it to the array, then don't allow that touch to subsequently move the ship. Remove on touches ended. I don't see anything wrong or hacky about this, except for this note in the UITouch docs:

A UITouch object is persistent throughout a multi-touch sequence. You should never retain an UITouch object when handling an event. If you need to keep information about a touch from one phase to another, you should copy that information from the UITouch object.

But the persistence seems to support what you want to do. I don't know if a different class is used in cocos2d but the principle remains the same.

Upvotes: 1

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