Question

我使用cocos2d-x的时间不长。它很有趣，很容易掌握。但最近，我在实施某些事情时陷入困境。（现在已经有一段时间了）。

我在X和Y轴上实现了Parllax。这是一件轻松的工作。但是当我尝试在Z轴上实现它时（想象一下透视图），我就是不能。

请提出建议。将非常感谢cocos2d-x的上下文解释。我在C ++中使用它。谢谢！

Answer 1

我在Z轴上编写了无限滚动背景的代码最重要的提示是我计算背景图块之间的距离。我使用背景图像的高度作为瓷砖之间的距离，但在我围绕X轴旋转精灵之前存储它。

以下是头文件（ LevelScene.h ）中定义的变量：

...
private:
   std::vector<Sprite*> mBackgrounds;  // background tiles 
   Layer* mlayer;                      // main layer where background tiles are in
   Camera* mMainCamera;                // main camera
   int count = 0;                      // number of tiles that fills distance between camera and its far plane
   float height = 1;                   // this is distance between each tile indeed
...

和 LevelScene.cpp 文件包含：

bool LevelsScene::init()
{
   if( !Layer::init() )
   {
       return false;
   }

   auto visibleSize = Director::getInstance()->getVisibleSize();
   auto origin = Director::getInstance()->getVisibleOrigin();

   mlayer = Layer::create();
   mlayer->setCameraMask( (unsigned short)CameraFlag::USER2 );
   addChild( mlayer );
   float far = 3500;
   mMainCamera = Camera::createPerspective(80, (float)visibleSize.width/visibleSize.height,
                                        1.0, far);
   mMainCamera->setCameraFlag(CameraFlag::USER2);
   this->addChild(mMainCamera);

   auto bg = Sprite::create();
   bg->initWithFile("asphalt.png");
   //The line below is very important. We use height of image as distance between tiles. We store height before rotating sprite.
   height = bg->getBoundingBox().size.height;

   bg->setRotation3D( Vec3(-90,0,0) );
   bg->setPosition3D( Vec3(visibleSize.width/2,0,-200 ) );
   bg->setCameraMask( (unsigned short)CameraFlag::USER2 );
   mlayer->addChild( bg );

   mMainCamera->setPosition3D(bg->getPosition3D() + Vec3(0,150,300));
   mMainCamera->lookAt(bg->getPosition3D()+Vec3(0,100,0), Vec3(0.0,1.0,0.0));

   float lastZ = bg->getPositionZ() - height;
   count = ceil(far/height) + 2;

   mBackgrounds.push_back( bg );
   for( int i = 0; i< count; i++ )
   {
      auto bg = Sprite::create();
      bg->initWithFile("asphalt.png");
      bg->setRotation3D( Vec3(-90,0,0) );
      bg->setPosition3D( Vec3(visibleSize.width/2,0, lastZ) );
      bg->setCameraMask( (unsigned short)CameraFlag::USER2 );
      mlayer->addChild( bg );
      lastZ = bg->getPositionZ() - height;
      mBackgrounds.push_back( bg );
   }

   scheduleUpdate();
   return true;
}

void LevelsScene::update(float dt)
{
    mMainCamera->setPosition3D( mMainCamera->getPosition3D() +
                            Vec3( 0, 0, -10) );
    for( std::vector<Sprite*>::iterator bgit = mBackgrounds.begin();
     bgit != mBackgrounds.end(); bgit++ )
   {
       Sprite* bg = (Sprite*)*bgit;
       if( bg->getPositionZ() > mMainCamera->getPositionZ() )
       {
           bg->setPositionZ( bg->getPositionZ() - height * count );
       }
   }
}

希望这有帮助：）

在cocos2d-x V3.10中实现Z轴上的视差

1 个答案: