Add 'game-sml/' from commit '113c3e67abe635f714f972a1e2ab0e4b24ff10f4'

git-subtree-dir: game-sml
git-subtree-mainline: aa5357714d
git-subtree-split: 113c3e67ab

game-sml/shell/input-state.sml

@@ -0,0 +1,95 @@
+structure InputState =
+struct
+  val keyMappings = ref
+    { left = CoreKey.KEY_S
+    , right = CoreKey.KEY_F
+    , down = CoreKey.KEY_D
+    , up = CoreKey.KEY_E
+    , attack = CoreKey.KEY_J
+    , jump = CoreKey.KEY_K
+    , escape = CoreKey.KEY_ESCAPE
+    }
+
+  fun setControls controls = keyMappings := controls
+
+  (* global state detecting button inputs *)
+  val state =
+    { leftHeld = ref false
+    , rightHeld = ref false
+    , upHeld = ref false
+    , downHeld = ref false
+    , jumpHeld = ref false
+    , attackHeld = ref false
+    , escapeHeld = ref false
+    , newKeys = ref []
+    , width = ref (1920.0 : Real32.real)
+    , height = ref (1080.0 : Real32.real)
+    }
+
+  fun getSnapshot () =
+    let
+      val input =
+        { leftHeld = !(#leftHeld state)
+        , rightHeld = !(#rightHeld state)
+        , upHeld = !(#upHeld state)
+        , downHeld = !(#downHeld state)
+        , attackHeld = !(#attackHeld state)
+        , jumpHeld = !(#jumpHeld state)
+        , escapeHeld = !(#escapeHeld state)
+        , newKeys = !(#newKeys state)
+        }
+      val () = #newKeys state := []
+    in
+      input
+    end
+
+  (* there are three action states reported by OS: PRESS, REPEAT and RELEASE. 
+   * If input is PRESS or REPEAT, then return true, or else return false. *)
+  fun actionToBool action = action <> Input.RELEASE
+
+  fun handleKey (key, action) =
+    case GlfwKeyMap.codeFromKey key of
+      SOME code =>
+        let
+          val () =
+            if action = Input.PRESS then
+              #newKeys state := code :: !(#newKeys state)
+            else
+              ()
+          val {left, right, down, up, attack, jump, escape} = !keyMappings
+          val action = actionToBool action
+        in
+          if code = left then #leftHeld state := action
+          else if code = up then #upHeld state := action
+          else if code = right then #rightHeld state := action
+          else if code = down then #downHeld state := action
+          else if code = attack then #attackHeld state := action
+          else if code = jump then #jumpHeld state := action
+          else if code = escape then #escapeHeld state := action
+          else ()
+        end
+    | NONE => ()
+
+  fun keyCallback (key, scancode, action, mods) =
+    if mods = 0 then handleKey (key, action) else ()
+
+  fun getWidth () =
+    !(#width state)
+
+  fun getHeight () =
+    !(#height state)
+
+  fun sizeCallback (width, height) =
+    (#width state := width; #height state := height)
+
+  fun registerCallbacks window =
+    let
+      val () = Input.exportKeyCallback keyCallback
+      val () = Input.setKeyCallback window
+
+      val () = Input.exportFramebufferSizeCallback sizeCallback
+      val () = Input.setFramebufferSizeCallback window
+    in
+      ()
+    end
+end