done refactoring functional core

functional-core/triangles.sml

@@ -0,0 +1,46 @@
+structure Triangles =
+struct
+  open AppType
+
+  local
+    fun helpToVector
+      (lst, acc, windowWidth, windowHeight, halfWidth, halfHeight) =
+      case lst of
+        {x1, y1, x2, y2, x3, y3} :: tl =>
+          let
+            val x1 = Ndc.centreAlignX (x1, windowWidth, windowHeight, halfWidth)
+            val x2 = Ndc.centreAlignX (x2, windowWidth, windowHeight, halfWidth)
+            val x3 = Ndc.centreAlignX (x3, windowWidth, windowHeight, halfWidth)
+
+            val y1 = Ndc.centreAlignY (y1, windowWidth, windowHeight, halfHeight)
+            val y2 = Ndc.centreAlignY (y2, windowWidth, windowHeight, halfHeight)
+            val y3 = Ndc.centreAlignY (y3, windowWidth, windowHeight, halfHeight)
+
+            val vec =
+             #[ x1 / halfWidth
+              , y1 / halfHeight
+              , x2 / halfWidth
+              , y2 / halfHeight
+              , x3 / halfWidth
+              , y3 / halfHeight
+              ]
+            val acc = vec :: acc
+          in
+            helpToVector
+              (tl, acc, windowWidth, windowHeight, halfWidth, halfHeight)
+          end
+      | [] => acc
+  in
+    fun toVector (app: app_type) =
+      let
+        val windowWidth = #windowWidth app
+        val windowHeight = #windowHeight app
+        val halfWidth = Real32.fromInt (windowWidth div 2)
+        val halfHeight = Real32.fromInt (windowHeight div 2)
+        val lst = helpToVector
+          (#triangles app, [], windowWidth, windowHeight, halfWidth, halfHeight)
+      in
+        Vector.concat lst
+      end
+  end
+end