standardize keyboard-based FlxCamera movement

projects/nat-flixel-desktop-playground/source/PlayState.kiss

@@ -117,36 +117,28 @@
     (+= uiCamera.y (* FlxG.mouse.wheel UI_SCROLL_FACTOR))
     // TODO allow changing the a scroll factor
 
-    // Control the UI camera with the arrow keys, and the playground camera with wasd:
+    // Control the UI camera with WASD, and the playground camera with arrow keys:
     (var KEYBOARD_SCROLL_SPEED 200)
-    (method cameraKeyControl [:FlxCamera camera :Void->Bool leftKey :Void->Bool rightKey :Void->Bool upKey :Void->Bool downKey]
-        // but not when textInput is focused
-        (unless (and textInput textInput.hasFocus)
-            (let [scrollPerSec (/ KEYBOARD_SCROLL_SPEED 60)
-                    &mut :FlxVector movement (new FlxPoint)]
-                (when (leftKey) (-= movement.x 1))
-                (when (rightKey) (+= movement.x 1))
-                (when (upKey) (-= movement.y 1))
-                (when (downKey) (+= movement.y 1))
-                (when (< 0 movement.length)
-                    (set movement (movement.normalize)))
-                (movement.scale scrollPerSec)
-                (+= camera.scroll.x movement.x)
-                (+= camera.scroll.y movement.y))))
+    
+    (FlxG.camera.updateKeyControl
+        elapsed
+        KEYBOARD_SCROLL_SPEED
+        ->{FlxG.keys.pressed.LEFT}
+        ->{FlxG.keys.pressed.RIGHT}
+        ->{FlxG.keys.pressed.UP}
+        ->{FlxG.keys.pressed.DOWN})
 
     // don't move the ui camera before ui has been placed -- new UI elements could appear offscreen
     (when (> uiGroup.length 0)
-        (cameraKeyControl uiCamera
-            ->{FlxG.keys.pressed.LEFT}
-            ->{FlxG.keys.pressed.RIGHT}
-            ->{FlxG.keys.pressed.UP}
-            ->{FlxG.keys.pressed.DOWN}))
-            
-    (cameraKeyControl FlxG.camera
-        ->{FlxG.keys.pressed.A}
-        ->{FlxG.keys.pressed.D}
-        ->{FlxG.keys.pressed.W}
-        ->{FlxG.keys.pressed.S}))
+        (unless (and textInput textInput.hasFocus)
+            (uiCamera.updateKeyControl
+                elapsed
+                KEYBOARD_SCROLL_SPEED
+                // TODO support dvorak
+                ->{FlxG.keys.pressed.A}
+                ->{FlxG.keys.pressed.D}
+                ->{FlxG.keys.pressed.W}
+                ->{FlxG.keys.pressed.S}))))
 
 (method :Void typeCommand []
     (enterText