Soft Body collapses in Cocos2D
#pragma mark - Touch Management

-(void) registerWithTouchDispatcher
{
    [[CCTouchDispatcher sharedDispatcher] addTargetedDelegate:self priority:0 swallowsTouches:YES];
}



- (BOOL)ccTouchBegan:(UITouch *)touch withEvent:(UIEvent *)event {
    BOOL beginTouch = NO;

    b2Vec2 ballVec = node.innerCircleBody->GetPosition();
    CGPoint ballPoint = CGPointMake((ballVec.x*PTM_RATIO)-node.radius, (ballVec.y*PTM_RATIO)-node.radius);

    CGPoint location = [touch locationInView:[touch view]];
    location = [[CCDirector sharedDirector] convertToGL:location];
    b2Vec2 locationWorld = b2Vec2(location.x/PTM_RATIO, location.y/PTM_RATIO);


    CGRect ballRect = CGRectMake(ballPoint.x, ballPoint.y, node.radius*2, node.radius*2);
    if (CGRectContainsPoint(ballRect, location)) {
        [node halt];

        b2MouseJointDef md;
        md.bodyA = groundBody;
        md.bodyB = node.innerCircleBody;
        md.target = locationWorld;
        md.collideConnected = true;
        md.maxForce = 1000.0f * node.innerCircleBody->GetMass();
        md.dampingRatio = 10.0f;
        md.frequencyHz = 100.f;

        _mouseJoint = (b2MouseJoint *)world->CreateJoint(&md);
        node.innerCircleBody->SetAwake(true);
        beginTouch = YES;
    }
    return beginTouch;
}

- (void)ccTouchMoved:(UITouch *)touch withEvent:(UIEvent *)event {
    if (_mouseJoint == NULL) return;

    CGPoint location = [touch locationInView:[touch view]];
    location = [[CCDirector sharedDirector] convertToGL:location];
    b2Vec2 locationWorld = b2Vec2(location.x/PTM_RATIO, location.y/PTM_RATIO);

    _mouseJoint->SetTarget(locationWorld);
}

- (void)ccTouchCancelled:(UITouch *)touch withEvent:(UIEvent *)event {
    if (_mouseJoint) {
        world->DestroyJoint(_mouseJoint);
        _mouseJoint = NULL;
    }
}

- (void)ccTouchEnded:(UITouch *)touch withEvent:(UIEvent *)event {
//    [node bounce];
    if (_mouseJoint == NULL) return;
    world->DestroyJoint(_mouseJoint);
    _mouseJoint = NULL;
}