CODEWITHSUNDEEP
ioscocos2d-iphonebox2dcollision
MichalMoskala
MichalMoskala

Reputation: 927

How to avoid collision force in box2D?

i'm creating simple iOS game with Cocos2D and Box2D. In my game user has to create full word by shooting to squares with letters. If shooted letter is correct the square should explode, otherwise the square should fall down. I have created simple contact listener and I can detect collision between bullet and square but the problem is how to avoid collision force when letter is incorrect? I that situation (incorrect letter) i want square to simply fall down without applying collision force to the square.

Maybe I can delete the square and create new one at the position of deleted, but i think it's not the best idea :)

Upvotes: 0

Views: 187

Answers (2)

North-Pole
North-Pole

Reputation: 630

The solution I would advice is to set the velocity of the bullet to 0 in both directions in the PreSolve callback of the contact listener. Obviously you do a check in the PreSolve function. This way as the function is called PreSolve, the collision calculation have not happened yet. so setting velocity to 0 will make the bullet to have no effect on the square in terms of force.

Upvotes: 0

Paddyd
Paddyd

Reputation: 1870

One suggestion I would make would be on collision, if the letter is incorrect, set the bodies x and z velocities to 0. This way when they collide with incorrect squares they will simply fall.

Another thing you could do would be to set the target square's body as fixed ( or rigid, I can't remember what it's called in Box2d off the top of my head). So even if an incorrect letter collides with it, it will not budge but the letter will bounce off it. And it the letter is correct, you can explode it as normal.

Upvotes: 1

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