begin title screen by adding title screen type

fcore/game-type.sml

@@ -1,6 +1,6 @@
 signature GAME_TYPE =
 sig
-  datatype mode = LEVEL of LevelType.level_type
+  datatype mode = LEVEL of LevelType.level_type | TITLE of TitleType.title_type
 
   type game_type = {userKeys: CoreKey.user_key, mode: mode}
 
@@ -9,12 +9,12 @@ end
 
 structure GameType :> GAME_TYPE =
 struct
-  datatype mode = LEVEL of LevelType.level_type
+  datatype mode = LEVEL of LevelType.level_type | TITLE of TitleType.title_type
 
   type game_type = {userKeys: CoreKey.user_key, mode: mode}
 
   fun init userKeys =
-    let val mode = LEVEL LevelType.initial
+    let val mode = TITLE TitleType.initial
     in {mode = mode, userKeys = userKeys}
     end
 end

fcore/game-update.sml

@@ -12,6 +12,10 @@ struct
             let val level = LevelUpdate.update (level, input)
             in LEVEL level
             end
+        | TITLE title =>
+            let val title = TitleUpdate.update (title, input)
+            in TITLE title
+            end
     in
       {mode = mode, userKeys = userKeys}
     end

fcore/level/level-update.sml

@@ -1,6 +1,6 @@
 structure LevelUpdate =
 struct
-  fun update (game, input) =
+  fun update (level, input) =
     let
       val
         { player
@@ -11,9 +11,9 @@ struct
         , enemies
         , graph
         , fallingEnemies
-        } = game
+        } = level
 
-      val player = Player.runPhysicsAndInput (game, input)
+      val player = Player.runPhysicsAndInput (level, input)
 
       val enemyTree = Enemy.generateTree enemies
       val player = Player.checkEnemyCollisions (player, enemies, enemyTree)

fcore/title/title-type.sml

@@ -0,0 +1,17 @@
+signature TITLE_TYPE =
+sig
+  datatype focus = START_BUTTON
+
+  type title_type = {focus: focus}
+
+  val initial: title_type
+end
+
+structure TitleType :> TITLE_TYPE =
+struct
+  datatype focus = START_BUTTON
+
+  type title_type = {focus: focus}
+
+  val initial = {focus = START_BUTTON}
+end

fcore/title/title-update.sml

@@ -0,0 +1,6 @@
+structure TitleUpdate =
+struct
+  open TitleType
+
+  fun update (titleState, input) = titleState
+end

oms.mlb

@@ -52,6 +52,9 @@ fcore/level/player/player-attack.sml
 fcore/level/projectile.sml
 fcore/level/level-update.sml
 
+fcore/title/title-type.sml
+fcore/title/title-update.sml
+
 fcore/game-type.sml
 fcore/game-update.sml
 

shell/gl-draw.sml

@@ -213,7 +213,7 @@ struct
   fun drawField ({fieldVertexBuffer, fieldProgram, fieldLength, ...}) =
     drawXyrgba (fieldVertexBuffer, fieldProgram, fieldLength)
 
-  fun drawLevel (shellState: t) =
+  fun helpDrawLevel (shellState: t) =
     let
       val _ = drawWall shellState
       val _ = drawPlayer shellState
@@ -222,12 +222,7 @@ struct
       ()
     end
 
-  fun drawMode (shellState: t, game: GameType.game_type) =
+  fun drawLevel (shellState: t, level) =
-    let
-      open GameType
-    in
-      case #mode game of
-        LEVEL level =>
     let
       val width = InputState.getWidth ()
       val height = InputState.getHeight ()
@@ -250,10 +245,18 @@ struct
       val shellState = uploadWall (shellState, wallVec)
       val shellState = uploadPlayer (shellState, playerVec)
       val shellState = uploadField (shellState, fieldVec)
-            val () = drawLevel shellState
+      val () = helpDrawLevel shellState
     in
       shellState
     end
+
+  fun drawMode (shellState: t, game: GameType.game_type) =
+    let
+      open GameType
+    in
+      case #mode game of
+        LEVEL level => drawLevel (shellState, level)
+      | TITLE title => shellState
     end
 
   fun helpLoop (shellState as {window, ...}: t, game) =