return normalised device coordinates together with vector, from getClickPos function

functional-core/app-update.sml

@@ -17,6 +17,7 @@ struct
       end
   end
 
+  local
     fun genClickPoints (windowWidth, windowHeight) =
       let
         val w = Real32.fromInt windowWidth / 40.0
@@ -25,13 +26,12 @@ struct
         Vector.tabulate (41, fn idx => Real32.fromInt idx * w)
       end
 
-  local
     val clickPoints = 
       genClickPoints (Constants.windowWidth, Constants.windowHeight)
 
     fun getVerticalClickPos (idx, horizontalPos, mouseX, mouseY, r, g, b) =
       if idx = Vector.length clickPoints then
-        #[]
+        (#[], 0.0, 0.0)
       else
         let
           val curVerticalPos = Vector.sub (clickPoints, idx)
@@ -49,7 +49,8 @@ struct
               val right = (hpos + 5.0) / halfWidth
               val bottom = (vpos - 5.0) / halfHeight
               val top = (vpos + 5.0) / halfHeight
-            in
+
+              val drawVec =
                 #[ left, bottom, r, g, b
                  , right, bottom, r, g, b
                  , left, top, r, g, b
@@ -58,12 +59,17 @@ struct
                  , right, bottom, r, g, b
                  , right, top, r, g, b
                  ]
+
+              val hpos = hpos / halfWidth
+              val vpos = vpos / halfHeight
+            in
+              (drawVec, hpos, vpos)
             end
         end
 
     fun getHorizontalClickPos (idx, mouseX, mouseY, r, g, b) =
       if idx = Vector.length clickPoints then
-        #[]
+        (#[], 0.0, 0.0)
       else
         let
           val curPos = Vector.sub (clickPoints, idx)
@@ -93,27 +99,31 @@ struct
       case inputMsg of
         MOUSE_MOVE {x = mouseX, y = mouseY} =>
           let
-            val _ = print "mouse moved\n"
+            val (drawVec, _, _) = getClickPos (mouseX, mouseY, 1.0, 0.0, 0.0)
-            val drawMsg = DRAW_BUTTON (getClickPos
+            val drawMsg = DRAW_BUTTON drawVec
-              (mouseX, mouseY, 1.0, 0.0, 0.0))
           in
             (model, drawMsg, mouseX, mouseY)
           end
       | MOUSE_LEFT_RELEASE =>
           let
-            val _ = print "mouse released\n"
+            val (drawVec, _, _) = getClickPos (mouseX, mouseY, 1.0, 0.0, 0.0)
-            val drawMsg = DRAW_BUTTON (getClickPos
+            val drawMsg = DRAW_BUTTON drawVec
-              (mouseX, mouseY, 1.0, 0.0, 0.0))
           in
             (model, drawMsg, mouseX, mouseY)
           end
       | MUSE_LEFT_CLICK =>
           let
-            val _ = print "mouse clicked\n"
+            val (buttonVec, hpos, vpos) = 
-            val buttonVec = getClickPos (mouseX, mouseY, 0.0, 0.0, 1.0)
+              getClickPos (mouseX, mouseY, 0.0, 0.0, 1.0)
+          in
+            if Vector.length buttonVec > 0 then
+              let
                 val drawMsg = DRAW_BUTTON buttonVec
               in
                 (model, drawMsg, mouseX, mouseY)
               end
+            else
+              (model, NO_DRAW, mouseX, mouseY)
+          end
     end
 end

imperative-shell/event-loop.sml

@@ -55,7 +55,15 @@ struct
                    , buttonDrawObject
                    , buttonDrawLength
                    )
-               end)
+               end
+           | NO_DRAW =>
+               draw
+                 ( drawMailbox
+                 , window
+                 , graphDrawObject
+                 , buttonDrawObject
+                 , buttonDrawLength
+                 ))
     else
       Glfw.terminate ()
 end

message-types/draw-msg.sml

@@ -1,9 +1,11 @@
 signature DRAW_MESSAGE =
 sig
   datatype t = DRAW_BUTTON of Real32.real vector
+             | NO_DRAW
 end
 
 structure DrawMessage :> DRAW_MESSAGE =
 struct 
   datatype t = DRAW_BUTTON of Real32.real vector 
+             | NO_DRAW
 end