b2PrismaticJoint位置不适合地面

Question

大家好我正在用cocos2d v1开发游戏，我正在使用box2d。我正在启用视网膜显示器。我正在创建一个桶。我想只在x轴上移动我的水桶，所以我做了一个b2PrismaticJoint，但问题是水桶不适合地面。这是我的代码：`CCSprite * tube = [CCSprite spriteWithFile：@“tube.png”];     tube.position = ccp（SCREEN_WIDTH / 2，SCREEN_HEIGHT / 2）;     [self addChild：tube];

b2BodyDef bucketBodyDef;
bucketBodyDef.type = b2_dynamicBody;
bucketBodyDef.position.Set(tube.contentSize.width/PTM_RATIO, tube.contentSize.height/PTM_RATIO);
bucketBodyDef.userData = tube;
tubeBody = world->CreateBody(&bucketBodyDef);

b2PolygonShape bucketShape;
bucketShape.SetAsBox(tube.contentSize.width/2/PTM_RATIO, tube.contentSize.height/2/PTM_RATIO);


// Create shape definition and add to body
b2FixtureDef bucketShapeDef;
bucketShapeDef.shape = &bucketShape;
bucketShapeDef.density = 10.0f;
bucketShapeDef.friction = 0.4f;
tubeFixture = tubeBody->CreateFixture(&bucketShapeDef);


[self createTubeFixtures];


// Restrict bucket along the x axis
b2PrismaticJointDef jointDef;
b2Vec2 worldAxis(1.0f, 0.0f);
jointDef.collideConnected = true;
jointDef.Initialize(tubeBody, groundBody,
                    tubeBody->GetWorldCenter(), worldAxis); 
world->CreateJoint(&jointDef);`

当我取下关节时一切都很好..请看附图。谢谢！

Answer 1

我犯了一个小错误，花了我两天！那就是设置身体的坐标：b2BodyDef bucketBodyDef; bucketBodyDef.type = b2_dynamicBody; **bucketBodyDef.position.Set(tube.contentSize.width/2/PTM_RATIO, tube.contentSize.height/2/PTM_RATIO);** bucketBodyDef.userData = tube; tubeBody = world->CreateBody(&bucketBodyDef);