anchor.diff:  open Foom.Renderer
   open Foom.Renderer.RendererSystem
   open Foom.Game.Assets
  +open Foom.Ecs
   
   let octahedron_vtx = 
       [|
  
positive.code:         input.Model.Set this.Model
  
  type SkyRendererComponent (textureKind : TextureKind) =
      inherit MeshRendererComponent<SkyInput, Sky> (0, MaterialDescription<SkyInput> (shader, textureKind), Sky ())
  
negative.code: 
  let shader = CreateShader SkyInput 2 (CreateShaderPass (fun _ -> [ Stencil2 ]) "Sky")//CreateShader "Sky" 2 ShaderPass.Stencil2 SkyInput
  
  type SkyMesh () =
      inherit Mesh<SkyInput> (skyVertices, [||], [||])
  
      member val Model = Matrix4x4.CreateScale (100.f)
  