public static Entity CreateCamera(this EntityWorld world, string tag, GraphicsDevice device)
 {
     var entity = world.CreateEntity();
     var camera = new Camera(device);
     entity.AddComponent(camera);
     entity.Tag = tag;
     return entity;
 }
 protected override void ProcessEntities(IDictionary<int, Entity> entities)
 {
     var previousRState = _device.RasterizerState;
     _device.RasterizerState = _antiAliasRasterizerState;
     _device.SamplerStates[0] = SamplerState.AnisotropicWrap;
     _camera = EntityWorld.GetActiveCamera();
     foreach(var entity in entities.Values)
     {
         var spaceObjectComponent = entity.GetComponent<SpaceObjectComponent>();
         if (spaceObjectComponent.Object is Planet)
             DrawPlanet(entity, (Planet)spaceObjectComponent.Object);
         else if (spaceObjectComponent.Object is Star)
             DrawStar(entity, (Star)spaceObjectComponent.Object);
     }
     _device.RasterizerState = previousRState;
 }