anchor.diff:  
       /// Make a Renderer.
       static member make (window : nativeint) (renderContext : nativeint) =
  -        
  +
           let glContext = SDL.SDL_GL_CreateContext (window)
   
           let program = Gl.CreateProgram ()
  
positive.code:         Gl.ClearColor (0.0f, 0.0f, 0.0f, 1.0f)
  
          let vertexData =
              [|-0.5f; -0.5f;
                +0.5f; -0.5f;
                +0.5f; +0.5f;
                -0.5f; +0.5f|]
          let mutable vertexBuffers = [|0u|]
          Gl.GenBuffers (1, vertexBuffers)
          let vertexBuffer = vertexBuffers.[0]
          Gl.BindBuffer (Gl.BufferTarget.ArrayBuffer, vertexBuffer)
          let vertexDataSize = IntPtr (2 * 4 * sizeof<single>)
          let vertexDataPtr = GCHandle.Alloc (vertexData, GCHandleType.Pinned)
          Gl.BufferData (Gl.BufferTarget.ArrayBuffer, vertexDataSize, vertexDataPtr.AddrOfPinnedObject(), Gl.BufferUsageHint.StaticDraw)
          
          let indexData = [|0u; 1u; 2u; 3u|]
          let mutable indexBuffers = [|0u|]
          Gl.GenBuffers (1, indexBuffers)
          let indexBuffer = indexBuffers.[0]
          Gl.BindBuffer (Gl.BufferTarget.ArrayBuffer, indexBuffer)
  
negative.code:         let indexDataPtr = GCHandle.Alloc (indexData, GCHandleType.Pinned)
          Gl.BufferData (Gl.BufferTarget.ArrayBuffer, indexDataSize, indexDataPtr.AddrOfPinnedObject(), Gl.BufferUsageHint.StaticDraw)
  
          let framebuffers = [|0u|]
          Gl.GenFramebuffers (1, framebuffers)
          let framebuffer = framebuffers.[0]
          Gl.BindFramebuffer (Gl.FramebufferTarget.Framebuffer, framebuffer)
  
          let frametextures = [|0u|]
          Gl.GenTextures (1, frametextures)
          let frametexture = frametextures.[0]
          Gl.BindTexture (Gl.TextureTarget.Texture2D, frametexture)
          Gl.TexImage2D (Gl.TextureTarget.Texture2D, 0, Gl.PixelInternalFormat.Rgba32f, Constants.Render.ResolutionX, Constants.Render.ResolutionY, 0, Gl.PixelFormat.Rgba, Gl.PixelType.Float, nativeint 0)
          Gl.TexParameteri (Gl.TextureTarget.Texture2D, Gl.TextureParameterName.TextureMinFilter, int Gl.TextureParameter.Nearest)
          Gl.TexParameteri (Gl.TextureTarget.Texture2D, Gl.TextureParameterName.TextureMagFilter, int Gl.TextureParameter.Nearest)
          Gl.FramebufferTexture (Gl.FramebufferTarget.Framebuffer, Gl.FramebufferAttachment.ColorAttachment0, frametexture, 0)
  
          let depthbuffers = [|0u|]
          Gl.GenRenderbuffers (1, depthbuffers)
          let depthbuffer = depthbuffers.[0]
          Gl.BindRenderbuffer (Gl.RenderbufferTarget.Renderbuffer, depthbuffer)
          Gl.RenderbufferStorage (Gl.RenderbufferTarget.Renderbuffer, Gl.RenderbufferStorageEnum.Depth32fStencil8, Constants.Render.ResolutionX, Constants.Render.ResolutionY)
          Gl.FramebufferRenderbuffer (Gl.FramebufferTarget.Framebuffer, Gl.FramebufferAttachment.DepthStencilAttachment, Gl.RenderbufferTarget.Renderbuffer, depthbuffer)
  
          while true do
  
              Gl.BindFramebuffer (Gl.FramebufferTarget.Framebuffer, framebuffer)
              Gl.DrawBuffers (1, [|Gl.DrawBuffersEnum.ColorAttachment0|])
              Gl.Viewport (0, 0, Constants.Render.ResolutionX, Constants.Render.ResolutionY)
              Gl.Clear (Gl.ClearBufferMask.ColorBufferBit ||| Gl.ClearBufferMask.DepthBufferBit ||| Gl.ClearBufferMask.StencilBufferBit)
  
              Gl.UseProgram program
              Gl.EnableVertexAttribArray lVertexPos2DAttrib
              Gl.BindBuffer (Gl.BufferTarget.ArrayBuffer, vertexBuffer)
  