finished coding export string, I think/hope

fcore/quad-tree.sml

@@ -524,12 +524,14 @@ struct
       val g = colToRealString g
       val b = colToRealString b
 
-      val x = String.concat ["((", x, " - halfWidth) / halfWidth)"]
+      val x = String.concat ["(((x + ", x, ") - halfWidth) / halfWidth)"]
-      val y = String.concat ["(~(", y, " - halfHeight) / halfHeight)"]
+      val y = String.concat ["(~(y + ", y, ") - halfHeight) / halfHeight)"]
 
       val ex = String.concat
         [ "((((("
+        , "("
         , ex
+        , "+ x)"
         , " - "
         , x
         , ") "
@@ -544,7 +546,9 @@ struct
         , "("
         , "("
         , "("
+        , "("
         , ey
+        , "+ y)"
         , " - "
         , y
         , ")"
@@ -554,14 +558,9 @@ struct
         ]
     in
       (* based on triangle order formed by `Ndc.ltrbToVertexRgb` function *)
-      x :: ey :: r :: g :: b ::
+      x :: ey :: r :: g :: b :: ex :: ey :: r :: g :: b :: x :: y :: r :: g :: b
-      ex :: ey :: r :: g :: b ::
+      :: x :: y :: r :: g :: b :: ex :: ey :: r :: g :: b :: ex :: y :: r :: g
-      x :: y :: r :: g :: b ::
+      :: b :: acc
-
-      x :: y :: r :: g :: b ::
-      ex :: ey :: r :: g :: b ::
-      ex :: y :: r :: g :: b ::
-      acc
     end
 
   fun toExportString (squares, canvasWidth, canvasHeight) =
@@ -573,8 +572,17 @@ struct
       val coords = BinTree.foldr (toExportStringFolder, bintree, [])
       val coords = String.concatWith "," coords
 
-      val header = ""
+      val header = String.concat
-      val footer = ""
+        [ "structure AAA = \nstruct\n"
+        , "  fun lerp (x, y, scale, windowWidth, windowHeight) =\n"
+        , "    let\n"
+        , "      val halfWidth = Real32.fromInt windowWidth / 2.0\n"
+        , "      val halfHeight = Real32.fromInt windowHeight / 2.0\n"
+        , "    in\n"
+        , "     #[\n"
+        ]
+
+      val footer = String.concat ["    end\n", "end\n"]
     in
       String.concat [header, coords, footer]
     end