anchor.diff:              //failwithf "[OpenVR] %A: %s" err str
   
       let depthRange = Range1d(0.15, 1000.0) |> Mod.init
  +    let mutable scaleFactor = 1.0
   
   
       let projections =
  
positive.code:         if OpenVR.Chaperone.GetPlayAreaRect(&quad) then
              let quad = 
                  Polygon3d [|
                      V3d(quad.vCorners0.v0, quad.vCorners0.v1, quad.vCorners0.v2)
                      V3d(quad.vCorners1.v0, quad.vCorners1.v1, quad.vCorners1.v2)
                      V3d(quad.vCorners2.v0, quad.vCorners2.v1, quad.vCorners2.v2)
                      V3d(quad.vCorners3.v0, quad.vCorners3.v1, quad.vCorners3.v2)
                  |]
              Some quad
          else
  
negative.code:     member x.DepthRange
          with get() = depthRange.Value
          and set r = transact (fun () -> depthRange.Value <- r)
  
      member x.ScaleFactor
          with get() = scaleFactor
          and set r = scaleFactor <- r
              
      member x.GetVulkanInstanceExtensions() = 
          let b = System.Text.StringBuilder(4096, 4096)
  