[Bf-blender-cvs] [979b2951542] master: Fix incorrect cursor motion coordinates for WIN32

[Campbell Barton]

Commit: 979b29515426710c48e56312e8c140f6bfb015aa
Author: Campbell Barton
Date:   Tue Dec 6 16:51:45 2022 +1100
Branches: master
https://developer.blender.org/rB979b29515426710c48e56312e8c140f6bfb015aa

Fix incorrect cursor motion coordinates for WIN32

Cursor motion events on windows read the position from GetCursorPos()
which wasn't always the same location stored in `lParam`.

In situations where events were handled immediately this wasn't often a
problem, for heavier scenes or when updates between event handling was
slow - many in-between cursor events would be incorrect.

This behavior dates back to the initial commit, there doesn't seem to be
a good reason not to use the cursor coordinates from the event.

Noticed when investigating T102346.

===================================================================

M	intern/ghost/intern/GHOST_SystemWin32.cpp
M	intern/ghost/intern/GHOST_SystemWin32.h

===================================================================

diff --git a/intern/ghost/intern/GHOST_SystemWin32.cpp b/intern/ghost/intern/GHOST_SystemWin32.cpp
index 3cc425d0ff3..7aef23b39b6 100644
--- a/intern/ghost/intern/GHOST_SystemWin32.cpp
+++ b/intern/ghost/intern/GHOST_SystemWin32.cpp
@@ -1049,9 +1049,9 @@ void GHOST_SystemWin32::processPointerEvent(
   }
 }
 
-GHOST_EventCursor *GHOST_SystemWin32::processCursorEvent(GHOST_WindowWin32 *window)
+GHOST_EventCursor *GHOST_SystemWin32::processCursorEvent(GHOST_WindowWin32 *window,
+                                                         const int32_t screen_co[2])
 {
-  int32_t x_screen, y_screen;
   GHOST_SystemWin32 *system = (GHOST_SystemWin32 *)getSystem();
 
   if (window->getTabletData().Active != GHOST_kTabletModeNone) {
@@ -1059,8 +1059,7 @@ GHOST_EventCursor *GHOST_SystemWin32::processCursorEvent(GHOST_WindowWin32 *wind
     return NULL;
   }
 
-  system->getCursorPosition(x_screen, y_screen);
-
+  int32_t x_screen = screen_co[0], y_screen = screen_co[1];
   if (window->getCursorGrabModeIsWarp()) {
     /* WORKAROUND:
      * Sometimes Windows ignores `SetCursorPos()` or `SendInput()` calls or the mouse event is
@@ -1834,7 +1833,10 @@ LRESULT WINAPI GHOST_SystemWin32::s_wndProc(HWND hwnd, uint msg, WPARAM wParam,
             }
           }
 
-          event = processCursorEvent(window);
+          const int32_t window_co[2] = {GET_X_LPARAM(lParam), GET_Y_LPARAM(lParam)};
+          int32_t screen_co[2];
+          window->clientToScreen(UNPACK2(window_co), UNPACK2(screen_co));
+          event = processCursorEvent(window, screen_co);
 
           break;
         }
@@ -1876,7 +1878,10 @@ LRESULT WINAPI GHOST_SystemWin32::s_wndProc(HWND hwnd, uint msg, WPARAM wParam,
           WINTAB_PRINTF("HWND %p mouse leave\n", window->getHWND());
           window->m_mousePresent = false;
           if (window->getTabletData().Active == GHOST_kTabletModeNone) {
-            event = processCursorEvent(window);
+            /* FIXME: document why the cursor motion event on mouse leave is needed. */
+            int32_t screen_co[2] = {0, 0};
+            system->getCursorPosition(screen_co[0], screen_co[1]);
+            event = processCursorEvent(window, screen_co);
           }
           GHOST_Wintab *wt = window->getWintab();
           if (wt) {
diff --git a/intern/ghost/intern/GHOST_SystemWin32.h b/intern/ghost/intern/GHOST_SystemWin32.h
index 98a7e5dfb35..b9263219e0f 100644
--- a/intern/ghost/intern/GHOST_SystemWin32.h
+++ b/intern/ghost/intern/GHOST_SystemWin32.h
@@ -331,7 +331,8 @@ class GHOST_SystemWin32 : public GHOST_System {
    * \param window: The window receiving the event (the active window).
    * \return The event created.
    */
-  static GHOST_EventCursor *processCursorEvent(GHOST_WindowWin32 *window);
+  static GHOST_EventCursor *processCursorEvent(GHOST_WindowWin32 *window,
+                                               const int32_t screen_co[2]);
 
   /**
    * Handles a mouse wheel event.