Added Widget::ObserveMouseWheel virtual method

include/JUI/Base/Widget.hpp

@@ -300,6 +300,7 @@ namespace JUI {
 
         virtual void InnerDraw() {}
 
+
         /// Renders the widget to the current OpenGL Context using JGL.
         /// The user should call this on their Scene instances only. JUI will handle the rest.
         virtual void Draw();
@@ -317,11 +318,19 @@ namespace JUI {
         /// See ReWindowIntegrationDemo for an example.
         virtual void ObserveMouseInput(MouseButton btn, bool pressed);
 
+        /// Informs a widget that the mouse wheel has been moved.
+        /// This is designed in such a way that the end-user can plug this into their existing code.
+        /// The user should call this on their Scene instances only. JUI will handle the rest.
+        /// See ReWindowIntegrationDemo for an example.
+        virtual void ObserveMouseWheel(int mwheel);
+
         /// Informs a widget that a key has been pressed or released.
         /// This is designed in such a way that the end-user can plug this into their existing code.
         /// The user should call this on their Scene instances only. JUI will handle the rest.
         /// See ReWindowIntegrationDemo for an example.
         virtual void ObserveKeyInput(Key key, bool pressed);
+
+
     protected:
         void DrawChildWidgets();
         void UpdateChildWidgets(float delta);

src/JUI/Base/Widget.cpp

@@ -587,6 +587,10 @@ Tween* Widget::TweenMarginBottom(const JUI::UDim& goal, JUI::TweenInfo info) {
     return t;
 }
 
+void Widget::ObserveMouseWheel(int mwheel) {
+    // TODO: Log that this is a stub.
+}
+
 /*
 Tween *Widget::TweenAnchorPoint(const Vector2 &goal, TweenInfo info) {
     Vector2 start = this->AnchorPoint();