anchor.diff:  
       let getRenderMessages absolute (viewBounds : Vector4) tileLayerClearance tileMapPosition tileMapDepth tileMapParallax (tileMap : TmxMap) =
           let layers = List.ofSeq tileMap.Layers
  -        let tileSourceSize = Vector2i (tileMap.TileWidth, tileMap.TileHeight)
  -        let tileSize = Vector2 (single tileMap.TileWidth, single tileMap.TileHeight)
  +        let tileSourceSize = v2i tileMap.TileWidth tileMap.TileHeight
  +        let tileSize = v2 (single tileMap.TileWidth) (single tileMap.TileHeight)
           let messagess =
               List.foldi
                   (fun i messagess (layer : TmxLayer) ->
  
positive.code:         | None -> None
  
      let tryGetDescriptor tileMapPosition (tileMap : TmxMap) =
          let tileSizeI = Vector2i (tileMap.TileWidth, tileMap.TileHeight)
          let tileSizeF = Vector2 (single tileSizeI.X, single tileSizeI.Y)
          let tileMapSizeM = Vector2i (tileMap.Width, tileMap.Height)
          let tileMapSizeI = Vector2i (tileMapSizeM.X * tileSizeI.X, tileMapSizeM.Y * tileSizeI.Y)
          let tileMapSizeF = Vector2 (single tileMapSizeI.X, single tileMapSizeI.Y)
          Some
              { TileMap = tileMap
                TileSizeI = tileSizeI; TileSizeF = tileSizeF
  
negative.code:                 match tileSetTile.Properties.TryGetValue Constants.TileMap.CollisionPropertyName with
                  | (true, cexpr) ->
                      let tileCenter =
                          v2
                              (td.TilePositionF.X + tmd.TileSizeF.X * 0.5f)
                              (td.TilePositionF.Y + tmd.TileSizeF.Y * 0.5f)
                      let tileBody =
                          match cexpr with
                          | "" -> BodyBox { Extent = tmd.TileSizeF * 0.5f; Center = tileCenter; PropertiesOpt = None }
  