8 files changed, 37 insertions, 1 deletions

diff --git a/intern/ghost/GHOST_C-api.h b/intern/ghost/GHOST_C-api.h
index 388d6eb96d2..c92e6ba78c1 100644
--- a/intern/ghost/GHOST_C-api.h
+++ b/intern/ghost/GHOST_C-api.h
@@ -907,6 +907,11 @@ extern int GHOST_UseNativePixels(void);
 extern int GHOST_SupportsCursorWarp(void);
 
 /**
+ * Support positioning windows (when false `wmWindow.x,y` are meaningless).
+ */
+extern int GHOST_SupportsWindowPosition(void);
+
+/**
  * Assign the callback which generates a back-trace (may be NULL).
  */
 extern void GHOST_SetBacktraceHandler(GHOST_TBacktraceFn backtrace_fn);
diff --git a/intern/ghost/GHOST_ISystem.h b/intern/ghost/GHOST_ISystem.h
index 436ff7a723e..d946d2d882a 100644
--- a/intern/ghost/GHOST_ISystem.h
+++ b/intern/ghost/GHOST_ISystem.h
@@ -313,6 +313,11 @@ class GHOST_ISystem {
   virtual bool supportsCursorWarp() = 0;
 
   /**
+   * Return true getting/setting the window position is supported.
+   */
+  virtual bool supportsWindowPosition() = 0;
+
+  /**
    * Focus window after opening, or put them in the background.
    */
   virtual void useWindowFocus(const bool use_focus) = 0;
diff --git a/intern/ghost/intern/GHOST_C-api.cpp b/intern/ghost/intern/GHOST_C-api.cpp
index 3bb7a7618c4..b1a15fdf4d7 100644
--- a/intern/ghost/intern/GHOST_C-api.cpp
+++ b/intern/ghost/intern/GHOST_C-api.cpp
@@ -835,6 +835,12 @@ int GHOST_SupportsCursorWarp(void)
   return system->supportsCursorWarp();
 }
 
+int GHOST_SupportsWindowPosition(void)
+{
+  GHOST_ISystem *system = GHOST_ISystem::getSystem();
+  return system->supportsWindowPosition();
+}
+
 void GHOST_SetBacktraceHandler(GHOST_TBacktraceFn backtrace_fn)
 {
   GHOST_ISystem::setBacktraceFn(backtrace_fn);
diff --git a/intern/ghost/intern/GHOST_System.cpp b/intern/ghost/intern/GHOST_System.cpp
index 2aad4f2ea29..c8308b3586b 100644
--- a/intern/ghost/intern/GHOST_System.cpp
+++ b/intern/ghost/intern/GHOST_System.cpp
@@ -395,6 +395,11 @@ bool GHOST_System::supportsCursorWarp()
   return true;
 }
 
+bool GHOST_System::supportsWindowPosition()
+{
+  return true;
+}
+
 void GHOST_System::initDebug(GHOST_Debug debug)
 {
   m_is_debug_enabled = debug.flags & GHOST_kDebugDefault;
diff --git a/intern/ghost/intern/GHOST_System.h b/intern/ghost/intern/GHOST_System.h
index 9f2fba1a2c6..b60ce09f743 100644
--- a/intern/ghost/intern/GHOST_System.h
+++ b/intern/ghost/intern/GHOST_System.h
@@ -152,6 +152,7 @@ class GHOST_System : public GHOST_ISystem {
   bool m_nativePixel;
 
   bool supportsCursorWarp(void);
+  bool supportsWindowPosition(void);
 
   /**
    * Focus window after opening, or put them in the background.
diff --git a/intern/ghost/intern/GHOST_SystemWayland.cpp b/intern/ghost/intern/GHOST_SystemWayland.cpp
index 93d85f33dda..d8fbe875f67 100644
--- a/intern/ghost/intern/GHOST_SystemWayland.cpp
+++ b/intern/ghost/intern/GHOST_SystemWayland.cpp
@@ -2682,6 +2682,14 @@ GHOST_TSuccess GHOST_SystemWayland::setCursorVisibility(bool visible)
 
 bool GHOST_SystemWayland::supportsCursorWarp()
 {
+  /* WAYLAND doesn't support setting the cursor position directly,
+   * this is an intentional choice, forcing us to use a software cursor in this case. */
+  return false;
+}
+
+bool GHOST_SystemWayland::supportsWindowPosition()
+{
+  /* WAYLAND doesn't support accessing the window position. */
   return false;
 }
 
diff --git a/intern/ghost/intern/GHOST_SystemWayland.h b/intern/ghost/intern/GHOST_SystemWayland.h
index 3be108b1f88..762ceb80e38 100644
--- a/intern/ghost/intern/GHOST_SystemWayland.h
+++ b/intern/ghost/intern/GHOST_SystemWayland.h
@@ -125,6 +125,7 @@ class GHOST_SystemWayland : public GHOST_System {
   GHOST_TSuccess setCursorVisibility(bool visible);
 
   bool supportsCursorWarp();
+  bool supportsWindowPosition();
 
   GHOST_TSuccess setCursorGrab(const GHOST_TGrabCursorMode mode,
                                const GHOST_TGrabCursorMode mode_current,
diff --git a/source/blender/windowmanager/intern/wm_event_system.cc b/source/blender/windowmanager/intern/wm_event_system.cc
index 658e643508e..e44016948fc 100644
--- a/source/blender/windowmanager/intern/wm_event_system.cc
+++ b/source/blender/windowmanager/intern/wm_event_system.cc
@@ -4942,7 +4942,11 @@ static void attach_ndof_data(wmEvent *event, const GHOST_TEventNDOFMotionData *g
 /* Imperfect but probably usable... draw/enable drags to other windows. */
 static wmWindow *wm_event_cursor_other_windows(wmWindowManager *wm, wmWindow *win, wmEvent *event)
 {
-  int mval[2] = {event->xy[0], event->xy[1]};
+  /* If GHOST doesn't support window positioning, don't use this feature at all. */
+  const static int8_t supports_window_position = GHOST_SupportsWindowPosition();
+  if (!supports_window_position) {
+    return nullptr;
+  }
 
   if (wm->windows.first == wm->windows.last) {
     return nullptr;
@@ -4951,6 +4955,7 @@ static wmWindow *wm_event_cursor_other_windows(wmWindowManager *wm, wmWindow *wi
   /* In order to use window size and mouse position (pixels), we have to use a WM function. */
 
   /* Check if outside, include top window bar. */
+  int mval[2] = {event->xy[0], event->xy[1]};
   if (mval[0] < 0 || mval[1] < 0 || mval[0] > WM_window_pixels_x(win) ||
       mval[1] > WM_window_pixels_y(win) + 30) {
     /* Let's skip windows having modal handlers now. */