Looking for the reference tutorials for the joints in the Box2D for iphone

Question

I can't find the tutorials of joints class in the Box2D for iPhone. I am unable to run a Testbed for iPhone Box2D.

(void)ccTouchesBegan:(NSSet *)touches withEvent:(UIEvent *)event
{
       if (_mouseJoint!=NULL)return;
       UITouch *mytouch=[touches anyObject];
       CGPoint location=[mytouch locationInView:[mytouch view]];
       location=[[CCDirector sharedDirector]convertToGL:location];
        b2Vec2 locationWorld=b2Vec2(location.x/PTM_RATIO,location.y/PTM_RATIO);
 //ristrict the player within the ground limit  keep stucking the player with grounditself..... 
if (_playerFixture->TestPoint(locationWorld))
{
    b2MouseJointDef md;
    md.bodyA=groundBody;
    md.bodyB=_playerBody;
    md.target=locationWorld; 
    md.collideConnected=true;
    md.maxForce=100.0f*_playerBody->GetMass();
    _mouseJoint=(b2MouseJoint *)_world->CreateJoint(&md);
    _playerBody->SetAwake(true);
}
}

-(void)ccTouchesMoved:(NSSet *)touches withEvent:(UIEvent *)event
{
if (_mouseJoint == NULL) return;
UITouch *myTouch = [touches anyObject];
CGPoint location = [myTouch locationInView:[myTouch view]];
location = [[CCDirector sharedDirector] convertToGL:location];
if (location.y<240.00&&location.y>=20.0f)
{
    b2Vec2 locationWorld = b2Vec2(location.x/PTM_RATIO, location.y/PTM_RATIO);
    _mouseJoint->SetTarget(locationWorld);  
}
}

- (void)ccTouchesEnded:(NSSet *)touches withEvent:(UIEvent *)event 
{
if (_mouseJoint) 
{


 _world->DestroyJoint(_mouseJoint);
    _mouseJoint = NULL;


  }  

}

Answer 1

Emanuele Feronato has some great joint tutorials for box2d. The tutorials are in Actionscript 3, but the basic principles are the same.

BTW, the as3 port of box2d sticks pretty closely to the naming convention of the original c++ box2d, so you'll just have to change syntax a bit to use it on the iPhone.

http://www.emanueleferonato.com/category/box2d/

Answer 2

Some joint tutorials here: http://www.iforce2d.net/b2dtut/joints-overview