`-\'

Menu.hs

@@ -3,8 +3,11 @@ module Menu (
   MmaMenu(..),
   MmaWindow(..),
   initialMenu,
-  ) where
+  selectButton,
+) where
+import Graphics.UI.GLUT
 
+import Rectangle
 import Util
 
 data MmaMenu = MmaMenu
@@ -57,6 +60,10 @@ data MmaButton = MmaButton
                    buttonState :: Bool
                  } deriving Show
 
+-- calculate a rectangle around the button
+selectButton :: MmaButton -> [Vertex2 GLdouble]
+selectButton b = vertexRect $ boxAroundRect (buttonRect b) 2.0
+
 data MmaWindow = MmaWindow
                  {
                    windowRect :: Rectangle,

Rectangle.hs

@@ -0,0 +1,32 @@
+module Rectangle (
+  Rectangle(..),
+  boxAroundRect,
+  vertexRect,
+) where
+import Graphics.UI.GLUT
+
+data Rectangle =
+  Rectangle
+  {
+    rectX :: GLdouble,
+    rectY :: GLdouble,
+    rectWidth :: GLdouble,
+    rectHeight :: GLdouble
+  } deriving (Show, Eq)
+
+-- return a list of four vertices for a rectangle, given position and size
+vertexRect :: Rectangle -> [Vertex2 GLdouble]
+vertexRect (Rectangle x y width height) =
+    [(Vertex2 (x-w) (y+h))
+    , (Vertex2 (x-w) (y-h))
+    , (Vertex2 (x+w) (y-h))
+    , (Vertex2 (x+w) (y+h))]
+    where
+      w = width / 2
+      h = height / 2
+
+boxAroundRect :: Rectangle -> GLdouble -> Rectangle
+boxAroundRect r i = r {
+                        rectWidth = rectWidth r + i,
+                        rectHeight = rectHeight r + i 
+                      }

Render.hs

@@ -5,6 +5,7 @@ import Graphics.UI.GLUT
 
 import Graphics
 import Menu
+import Rectangle
 import Sprite
 import State
 import Util
@@ -28,7 +29,6 @@ drawIntro e t = do
   drawTexture 0 0 (introTexture t) 0.25
   drawTexture 0 y (introTexture t) 1
 
-
 drawSprite :: Sprite -> IO ()
 drawSprite s = do
   currentColor $= Color4 0.2 0 0.3 0
@@ -54,7 +54,12 @@ drawMenu m t = do
   drawButton (nextFrameButton m) (nextFrameButtonTexture t)
   drawButton (prevFrameButton m) (prevFrameButtonTexture t)
 
-
 drawButton :: MmaButton -> MmaTexture -> IO ()
-drawButton (MmaButton r _) tex = do
-  drawTexture (rectX r) (rectY r) tex 1
+drawButton b tex = do
+  drawTexture (rectX (buttonRect b)) (rectY (buttonRect b)) tex 1
+
+  if buttonState b
+    then do
+      currentColor $= Color4 0.85 0 0.4 0.2
+      renderPrimitive Quads $ mapM_ vertex $ selectButton b
+    else return ()

Sprite.hs

@@ -1,17 +1,15 @@
 module Sprite (
   Sprite(..),
-  Rectangle(..),
   makeSprite,
   spritePoints,
   selectPoints,
   initDragSprite,
   dragSprite,
   within,
-
-  vertexRect,
 ) where
 import Graphics.UI.GLUT
 
+import Rectangle
 import Util
 
 data Sprite =
@@ -36,12 +34,7 @@ spritePoints s = vertexRect $ rectangle s
 
 -- calculate a rectangle around the sprite
 selectPoints :: Sprite -> [Vertex2 GLdouble]
-selectPoints s = vertexRect $ r
-                                { rectWidth = rectWidth r + 8.0,
-                                  rectHeight = rectHeight r + 8.0
-                                }
-                                  where
-                                    r = rectangle s
+selectPoints s = vertexRect $ boxAroundRect (rectangle s) 8.0
 
 -- start dragging a sprite
 initDragSprite :: Position -> Sprite -> Sprite
@@ -70,13 +63,3 @@ within (Position px py) (Sprite (Rectangle rx ry rw rh) _ _ _ _) =
       x = conv px
       y = conv py
 
--- return a list of four vertices for a rectangle, given position and size
-vertexRect :: Rectangle -> [Vertex2 GLdouble]
-vertexRect (Rectangle x y width height) =
-    [(Vertex2 (x-w) (y+h))
-    , (Vertex2 (x-w) (y-h))
-    , (Vertex2 (x+w) (y-h))
-    , (Vertex2 (x+w) (y+h))]
-    where
-      w = width / 2
-      h = height / 2

Util.hs

@@ -5,7 +5,6 @@ module Util (
     Pos,
     MmaTexture(..),
     MmaTextures(..),
-    Rectangle(..),
 ) where
 import Graphics.UI.GLUT
 
@@ -31,15 +30,6 @@ posConv (Position x y) = (conv x,conv y)
 posOp :: (GLdouble -> GLdouble -> GLdouble) -> Pos -> Pos -> Pos
 posOp op (a,b) (x,y) = (a `op` x, b `op` y)
 
-data Rectangle =
-  Rectangle
-  {
-    rectX :: GLdouble,
-    rectY :: GLdouble,
-    rectWidth :: GLdouble,
-    rectHeight :: GLdouble
-  } deriving (Show, Eq)
-
 data MmaTexture = MmaTexture
                   {
                     textureWidth :: GLsizei,