x11: Fix pointer warp on XWayland

XWayland seems to require that the pointer be hidden when it is warped, so hide and show the pointer when warping, if required.

Note that XWayland still only allows warping within the window, so attempts to warp to global coordinates outside the window won't work.

(cherry picked from commit a845c7027e68ff1c75bf814819d8e6b22499d899)
(cherry picked from commit 863d4a0f2ad22ff1460285e3084ff225e44eb49c)

src/video/x11/SDL_x11mouse.c

@@ -317,8 +317,19 @@ static void WarpMouseInternal(Window xwindow, const int x, const int y)
 {
     SDL_VideoData *videodata = (SDL_VideoData *)SDL_GetVideoDevice()->driverdata;
     Display *display = videodata->display;
-#ifdef SDL_VIDEO_DRIVER_X11_XINPUT2
+    SDL_Mouse *mouse = SDL_GetMouse();
     int deviceid = 0;
+    SDL_bool warp_hack = SDL_FALSE;
+
+    /* XWayland will only warp the cursor if it is hidden, so this workaround is required. */
+    if (videodata->is_xwayland && mouse && mouse->cursor_shown) {
+        warp_hack = SDL_TRUE;
+    }
+
+    if (warp_hack) {
+        X11_ShowCursor(NULL);
+    }
+#ifdef SDL_VIDEO_DRIVER_X11_XINPUT2
     if (X11_Xinput2IsInitialized()) {
         /* It seems XIWarpPointer() doesn't work correctly on multi-head setups:
          * https://developer.blender.org/rB165caafb99c6846e53d11c4e966990aaffc06cea
@@ -335,6 +346,10 @@ static void WarpMouseInternal(Window xwindow, const int x, const int y)
     {
         X11_XWarpPointer(display, None, xwindow, 0, 0, 0, 0, x, y);
     }
+
+    if (warp_hack) {
+        X11_ShowCursor(SDL_GetCursor());
+    }
     X11_XSync(display, False);
     videodata->global_mouse_changed = SDL_TRUE;
 }

src/video/x11/SDL_x11video.c

@@ -145,6 +145,12 @@ static int X11_SafetyNetErrHandler(Display *d, XErrorEvent *e)
     return 0;
 }
 
+static SDL_bool X11_IsXWayland(Display *d)
+{
+    int opcode, event, error;
+    return X11_XQueryExtension(d, "XWAYLAND", &opcode, &event, &error) == True;
+}
+
 static SDL_VideoDevice *X11_CreateDevice(void)
 {
     SDL_VideoDevice *device;
@@ -322,6 +328,8 @@ static SDL_VideoDevice *X11_CreateDevice(void)
     device->Vulkan_CreateSurface = X11_Vulkan_CreateSurface;
 #endif
 
+    data->is_xwayland = X11_IsXWayland(x11_display);
+
     return device;
 }
 

src/video/x11/SDL_x11video.h

@@ -156,6 +156,8 @@ typedef struct SDL_VideoData
     SDL_bool is_steam_deck;
     SDL_bool steam_keyboard_open;
 
+    SDL_bool is_xwayland;
+
 } SDL_VideoData;
 
 extern SDL_bool X11_UseDirectColorVisuals(void);