在box2d中使用鼠标关节（无触摸）将动态主体移动到目标位置

Question

我正在尝试使用鼠标关节将球（动态体）移动到目标位置。

我有一个拍摄按钮，当我点击它时，我正在调用这个方法来创建我的球。

-(void) addNewSpriteAtPosition:(CGPoint)p withAngle:(CGFloat)angle
{
    CCLOG(@"Add sprite %0.2f x %02.f",p.x,p.y);

    angle = 270-angle;
    sprite1 = [PhysicsSprite spriteWithTexture:spriteTexture_ rect:CGRectMake(0 ,0 ,22,22)];                        
    [self addChild:sprite1 z:0 tag:1111];
    [spritesToRemoveArray addObject:sprite1];
    sprite1.rotation = angle;
    sprite1.position = ccp( p.x, p.y);

    // Define the dynamic body.
    //Set up a 1m squared box in the physics world

    bodyDef.type = b2_dynamicBody;
    bodyDef.position.Set(p.x/PTM_RATIO, p.y/PTM_RATIO-1.0);
    bodyDef.userData = sprite1;
    _footballBody = world->CreateBody(&bodyDef);
    _footballBody->SetUserData(sprite1);
    // Define another box shape for our dynamic body.
    b2CircleShape dynamicBox;
    dynamicBox.m_radius = 0.35f;
    //dynamicBox.(.5f, .5f);//These are mid points for our 1m box

    // Define the dynamic body fixture.
    b2FixtureDef fixtureDef;
    fixtureDef.shape = &dynamicBox; 
    fixtureDef.density = 20.0f;
    fixtureDef.friction = 0.9f;
    fixtureDef.restitution = 0.6f;
    fixtureDef.userData = sprite1;
    fixtureDef.filter.groupIndex = -1;
    _footballFixture = _footballBody->CreateFixture(&fixtureDef);
    [sprite1 setPhysicsBody:_footballBody];



    float angle1 = CC_DEGREES_TO_RADIANS(angle);
    b2Vec2 vect = b2Vec2(cos(angle1)*120, sin(angle1)*120);
    b2Vec2 PointVector = _footballBody->GetPosition();
    _footballBody->ApplyLinearImpulse(vect,PointVector);


    b2Vec2 targetPos = b2Vec2(body1->GetPosition());
    //if (_footballFixture->TestPoint(_footballBody->GetPosition())) {
    NSLog(@"\n Target postion = <%f,%f>",targetPos.x,targetPos.y);
    NSLog(@"\n football position = <%f,%f>",_footballBody->GetPosition().x/32.0,_footballBody->GetPosition().y/32.0);

        b2MouseJointDef md;
        md.bodyA = _groundBody;
        md.bodyB = _footballBody;
        md.target = targetPos;
        md.collideConnected = true;
        md.maxForce = 1000.0f * _footballBody->GetMass();
//        md.dampingRatio = 0;
//        md.frequencyHz = 100;
        _mouseJoint = (b2MouseJoint *) world->CreateJoint(&md);
        _footballBody->SetAwake(true);
    //}




}

实际上当我这样做时，球应该移动到目标点，但是在这里使用上面的方法，球在它创建的点浮动并且慢慢地移动到左边缘的右边缘。

我需要您身边的建议我该如何解决这个问题。

非常感谢任何人的帮助。

全心全意，