在 Box2D 中，如何修复 body 的旋转

Question

我正在使用 cocos2d-x 的 box2d。

像这张照片，我的字符是盒子形状 body,

我的角色在被击中时会旋转。

但我希望我的字符 body 没有旋转。

我知道精灵为什么不旋转。

但我不知道如何修复 body 的旋转。

myChar 的代码

    void HelloWorld::makeMe()
    {   
        Sprite* pSprite = Sprite::create("shipBeige_manned.png");
        pSprite->setPosition(Vec2(100,100));
        this->addChild(pSprite);    
        b2BodyDef bodyDef;
        bodyDef.type = b2_dynamicBody;
        bodyDef.position.Set(100 / PTM_RATIO, 100 / PTM_RATIO);
        bodyDef.userData = pSprite;

        b2Body* body = _world->CreateBody(&bodyDef);

        b2PolygonShape pho;
        pho.SetAsBox(1.24f, 1.22f); 

        b2FixtureDef fixtureDef;

        fixtureDef.shape = &pho;

        fixtureDef.density = 1.0f;

        fixtureDef.friction = 0.2f;

        fixtureDef.restitution = 0.0f;
        body->CreateFixture(&fixtureDef);


        pSprite->setName("me");
    }

更新（打勾）代码

    void HelloWorld::tick(float dt)
    {   


        int velocityIterations = 8;
        int positionIterations = 3;

        _world->Step(dt, velocityIterations, positionIterations);


        for (b2Body* b = _world->GetBodyList(); b; b = b->GetNext())
        {
            if (b->GetUserData() != nullptr) {
                Sprite* spriteData = (Sprite *)b->GetUserData();
                spriteData->setPosition(Vec2(b->GetPosition().x * PTM_RATIO,
                    b->GetPosition().y * PTM_RATIO));
                spriteData->setRotation(-1 * CC_RADIANS_TO_DEGREES(b->GetAngle()));
            }
        }
    }

Answer 1

我对 Char 的 body 使用 SetFixedRotation。

    void HelloWorld::makeMe()
    {   
        Sprite* pSprite = Sprite::create("shipBeige_manned.png");
        pSprite->setPosition(Vec2(100,100));
        this->addChild(pSprite);    
        b2BodyDef bodyDef;
        bodyDef.type = b2_dynamicBody;
        bodyDef.position.Set(100 / PTM_RATIO, 100 / PTM_RATIO);
        bodyDef.userData = pSprite;

        b2Body* body = _world->CreateBody(&bodyDef);
        body->SetFixedRotation(true);  <----add this code
        b2PolygonShape pho;
        pho.SetAsBox(1.24f, 1.22f); 

        b2FixtureDef fixtureDef;

        fixtureDef.shape = &pho;
            // 밀도
        fixtureDef.density = 1.0f;
        // 마찰력 - 0 ~ 1
        fixtureDef.friction = 0.2f;
        // 반발력 - 물체가 다른 물체에 닿았을때 팅기는 값
        fixtureDef.restitution = 0.0f;
        body->CreateFixture(&fixtureDef);


        pSprite->setName("me");
    }

在 Box2D 中，如何修复 body 的旋转

In Box2D, how to fix body's rotation

c++

box2d

cocos2d-x