A fast, easy to use, free, and community supported 2D game engine
hezi
Member
Hi!
i'm using cocos2d to build an iphone game.
my game currently has two sprites: one for the main character and another for an item i should carry once he gets on him.
the main character and the item are both box2d bodies. i can detect the collision between the two. what is want is to make the item body stick to the main character body when they meet, that way any movement of the main character would also affect the item.
any suggestions on how to implement this?
thanks!
indy2005
Member
perhaps a distance joint if you want the item to remain a fixed distance. You would want to enable the object and the character to collide I guess, so you need to set this in the joint also...but set the distance joint long enough so they arent forced to collide.
sorry, too late for detail but look at the Box2D demo in Cocos2D, make it the active target and there is a distance joint demo.
I believe Box2d supports adding multiple shapes to one body which would be more efficient than using joints... however its more work for you, you'd have to recalculate the center of gravity, moment of inertia, set a new mass, get rid of the 2nd body the sticky thing was using.... perhaps not worth the effort, so joints might be the way to go.
I might be thinking too simple here, but I'd just 'manually' update the position of the held item based on the position of the main character, making sure to flag them as non-colliding when picked-up (else they will not want to overlap). You can fake some wobble effect when running, if you want.
In other words, I wouldnt merge the 2 bodies or use a joint (unless it needs to be super realistic physics on the item). I assume the character will need to drop/pick-up different items etc.
I have a similar situation and am trying to create a box2d weld joint which I can not get to work for the life of me. Must be a major brain fart. Anyway, I have two b2CircleShapes and when the collide, I want to create a b2WeldJoint on the point of where they touch. I have looked for examples of weld joint coding, but I have not found too much in relation to weld joints.
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