anchor.diff:  namespace Nu
   open System
   open System.Collections.Generic
  +open System.Linq
   open System.Numerics
   open System.IO
   open SDL2
  
positive.code:             SDL.SDL_SetRenderDrawBlendMode (renderContext, SDL.SDL_BlendMode.SDL_BLENDMODE_ADD) |> ignore
              let viewAbsolute = (Math.getViewAbsoluteI eyeCenter eyeSize).InvertedView ()
              let viewRelative = (Math.getViewRelativeI eyeCenter eyeSize).InvertedView ()
              messages.Sort SdlRenderer.compareDescriptors
              for message in messages do
                  SdlRenderer.renderDescriptor (&viewAbsolute, &viewRelative, eyeCenter, eyeSize, message.RenderDescriptor, renderer)
          | _ ->
  
negative.code:     /// Handle render clean up by freeing all loaded render assets.
      abstract CleanUp : unit -> Renderer
  
  type RenderLayeredMessageComparer () =
      interface IComparer<RenderLayeredMessage> with
          member this.Compare (left, right) =
              let elevationCompare = left.Elevation.CompareTo right.Elevation
              if elevationCompare <> 0 then elevationCompare else
              let positionYCompare = -(left.PositionY.CompareTo right.PositionY)
              if positionYCompare <> 0 then positionYCompare else
              let assetNameCompare = strCmp left.AssetTag.AssetName right.AssetTag.AssetName
              if assetNameCompare <> 0 then assetNameCompare else
              strCmp left.AssetTag.PackageName right.AssetTag.PackageName
  
  /// The mock implementation of Renderer.
  type [<ReferenceEquality; NoComparison>] MockRenderer =
      private
  