change ClickPoints.getMousePosition function to return indices to the click points array rather than the click points themselves; this will help adding functionality to use arrows for selecting click points later

functional-core/app/app-update.sml

@@ -17,11 +17,16 @@ struct
     let
       val drawVec =
         case ClickPoints.getClickPositionFromMouse model of
-          SOME (xpos, ypos) =>
+          SOME (hIdx, vIdx) =>
-            ClickPoints.getDrawDot (xpos, ypos, 1.0, 0.0, 0.0, model)
+            let
+              val xpos = Vector.sub (#xClickPoints model, hIdx)
+              val ypos = Vector.sub (#yClickPoints model, vIdx)
+            in
+              ClickPoints.getDrawDot (xpos, ypos, 1.0, 0.0, 0.0, model)
+            end
         | NONE => Vector.fromList []
       val drawVec = TriangleStage.toVector (model, drawVec)
-      
+
       val drawMsg = DRAW_DOT drawVec
     in
       (model, DRAW drawMsg)
@@ -29,11 +34,15 @@ struct
 
   fun mouseLeftClick (model: app_type) =
     case ClickPoints.getClickPositionFromMouse model of
-      SOME (xpos, ypos) =>
+      SOME (hIdx, vIdx) =>
         let
+          val {windowWidth, windowHeight, xClickPoints, yClickPoints, ...} =
+            model
+
+          val xpos = Vector.sub (xClickPoints, hIdx)
+          val ypos = Vector.sub (yClickPoints, vIdx)
           val dotVec = ClickPoints.getDrawDot (xpos, ypos, 0.0, 0.0, 1.0, model)
-          
+
-          val {windowWidth, windowHeight, ...} = model
           val halfWidth = Real32.fromInt (windowWidth div 2)
           val halfHeight = Real32.fromInt (windowHeight div 2)
           val hpos =

functional-core/app/click-points.sml

@@ -1,8 +1,7 @@
 signature CLICK_POINTS =
 sig
   val generate: int * int -> Real32.real vector
-  val getClickPositionFromMouse: AppType.app_type
+  val getClickPositionFromMouse: AppType.app_type -> (int * int) option
-                                 -> (Real32.real * Real32.real) option
   val getDrawDot:
     Real32.real
     * Real32.real
@@ -46,14 +45,14 @@ struct
         if mousePos < curPos - range orelse mousePos > curPos + range then
           getClickPos (clickPoints, mousePos, idx + 1)
         else
-          SOME (Vector.sub (clickPoints, idx))
+          SOME idx
       end
 
   fun getClickPositionFromMouse (app: AppType.app_type) =
     case getClickPos (#xClickPoints app, #mouseX app, 0) of
-      SOME xPos =>
+      SOME hIdx =>
         (case getClickPos (#yClickPoints app, #mouseY app, 0) of
-           SOME yPos => SOME (xPos, yPos)
+           SOME vIdx => SOME (hIdx, vIdx)
          | NONE => NONE)
     | NONE => NONE