add flipx and flipy

source/funkin/data/stage/StageData.hx

@@ -118,6 +118,22 @@ typedef StageDataProp =
   @:default(false)
   var isPixel:Bool;
 
+  /**
+   * If set to true, the prop will be flipped horizontally.
+   * @default false
+   */
+  @:optional
+  @:default(false)
+  var flipX:Bool;
+
+  /**
+   * If set to true, the prop will be flipped vertically.
+   * @default false
+   */
+  @:optional
+  @:default(false)
+  var flipY:Bool;
+
   /**
    * Either the scale of the prop as a float, or the [w, h] scale as an array of two floats.
    * Pro tip: On pixel-art levels, save the sprite small and set this value to 6 or so to save memory.

source/funkin/play/stage/Stage.hx

@@ -258,6 +258,9 @@ class Stage extends FlxSpriteGroup implements IPlayStateScriptedClass implements
 
       propSprite.zIndex = dataProp.zIndex;
 
+      propSprite.flipX = dataProp.flipX;
+      propSprite.flipY = dataProp.flipY;
+
       switch (dataProp.animType)
       {
         case 'packer':