add in support for passing down the "natural" (or flipped) scrolling direction in the MouseWheelEvent event

include/SDL_events.h

@@ -260,6 +260,7 @@ typedef struct SDL_MouseWheelEvent
     Uint32 which;       /**< The mouse instance id, or SDL_TOUCH_MOUSEID */
     Sint32 x;           /**< The amount scrolled horizontally, positive to the right and negative to the left */
     Sint32 y;           /**< The amount scrolled vertically, positive away from the user and negative toward the user */
+    Uint32 direction;   /**< Set to one of the SDL_MOUSEWHEEL_* defines. When FLIPPED the values in X and Y will be opposite. Multiply by -1 to change them back */
 } SDL_MouseWheelEvent;
 
 /**

include/SDL_mouse.h

@@ -60,6 +60,15 @@ typedef enum
     SDL_NUM_SYSTEM_CURSORS
 } SDL_SystemCursor;
 
+/**
+ * \brief Scroll direction types for the Scroll event
+ */
+typedef enum
+{
+    SDL_MOUSEWHEEL_NORMAL,    /**< The scroll direction is normal */
+    SDL_MOUSEWHEEL_FLIPPED    /**< The scroll direction is flipped / natural */
+} SDL_MouseWheelDirection;
+
 /* Function prototypes */
 
 /**