From 370c5aa33fc094fed2cb0aab1ad6e47fce63df60 Mon Sep 17 00:00:00 2001
From: Sam Lantinga <slouken@libsdl.org>
Date: Mon, 11 Feb 2013 21:29:36 -0800
Subject: [PATCH] Fixed mouse wheel delta on Windows

---
 src/video/windows/SDL_windowsevents.c | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/src/video/windows/SDL_windowsevents.c b/src/video/windows/SDL_windowsevents.c
index 7f0eef4cc..6b14034da 100644
--- a/src/video/windows/SDL_windowsevents.c
+++ b/src/video/windows/SDL_windowsevents.c
@@ -291,7 +291,8 @@ WIN_WindowProc(HWND hwnd, UINT msg, WPARAM wParam, LPARAM lParam)
 
     case WM_MOUSEWHEEL:
         {
-            int motion = (short) HIWORD(wParam);
+            // FIXME: This may need to accumulate deltas up to WHEEL_DELTA
+            short motion = GET_WHEEL_DELTA_WPARAM(wParam) / WHEEL_DELTA;
 
             SDL_SendMouseWheel(data->window, 0, motion);
             break;