commit 41c2cd24e6079e0883c1fde4230864343c7a05e8
Author:     Simon Howard <fraggle@gmail.com>
AuthorDate: Thu Feb 2 20:34:09 2012 +0000
Commit:     Simon Howard <fraggle@gmail.com>
CommitDate: Thu Feb 2 20:34:09 2012 +0000

    Only use the SDL mouse lag workaround on Windows - not all systems allow
    the cursor to be changed. This fixes Chocolate Doom on AmigaOS (thanks
    Timo Sievänen).

    Subversion-branch: /trunk/chocolate-doom
    Subversion-revision: 2483
---
 src/i_video.c | 45 ++++++++++++++++++++++++++++++++++++---------
 1 file changed, 36 insertions(+), 9 deletions(-)

diff --git a/src/i_video.c b/src/i_video.c
index d671a228..895043da 100644
--- a/src/i_video.c
+++ b/src/i_video.c
@@ -276,6 +276,37 @@ static void UpdateFocus(void)
     screenvisible = (state & SDL_APPACTIVE) != 0;
 }

+// Show or hide the mouse cursor. We have to use different techniques
+// depending on the OS.
+
+static void ShowCursor(boolean show)
+{
+    // On Windows, using SDL_ShowCursor() adds lag to the mouse input,
+    // so work around this by setting an invisible cursor instead. On
+    // other systems, it isn't possible to change the cursor, so this
+    // hack has to be Windows-only. (Thanks to entryway for this)
+
+#ifdef _WIN32
+    if (show)
+    {
+        SDL_SetCursor(cursors[1]);
+    }
+    else
+    {
+        SDL_SetCursor(cursors[0]);
+    }
+#else
+    SDL_ShowCursor(show);
+#endif
+
+    // When the cursor is hidden, grab the input.
+
+    if (!screensaver_mode)
+    {
+        SDL_WM_GrabInput(!show);
+    }
+}
+
 static void LoadDiskImage(void)
 {
     patch_t *disk;
@@ -423,12 +454,10 @@ void I_ShutdownGraphics(void)
 {
     if (initialized)
     {
-        SDL_SetCursor(cursors[1]);
-        SDL_ShowCursor(1);
-        SDL_WM_GrabInput(SDL_GRAB_OFF);
+        ShowCursor(true);

         SDL_QuitSubSystem(SDL_INIT_VIDEO);
-
+
         initialized = false;
     }
 }
@@ -725,17 +754,15 @@ static void UpdateGrab(void)
     {
         // Hide the cursor in screensaver mode

-        SDL_SetCursor(cursors[0]);
+        ShowCursor(false);
     }
     else if (grab && !currently_grabbed)
     {
-        SDL_SetCursor(cursors[0]);
-        SDL_WM_GrabInput(SDL_GRAB_ON);
+        ShowCursor(false);
     }
     else if (!grab && currently_grabbed)
     {
-        SDL_SetCursor(cursors[1]);
-        SDL_WM_GrabInput(SDL_GRAB_OFF);
+        ShowCursor(true);
     }

     currently_grabbed = grab;