From 44f50c647ed4a9fe376ec6423a198367702407fd Mon Sep 17 00:00:00 2001
From: Sam Lantinga <slouken@libsdl.org>
Date: Tue, 9 Jun 2020 21:47:41 -0700
Subject: [PATCH] Fixed bug 5171 - PollEvent impacts performance in 2.0.12

On some systems, GetClipCursor() impacts performance when called frequently, so only call it every once in a while to make sure we haven't lost our capture.
---
 src/video/windows/SDL_windowsevents.c | 13 +++++++++++--
 src/video/windows/SDL_windowswindow.c |  3 ++-
 src/video/windows/SDL_windowswindow.h |  1 +
 3 files changed, 14 insertions(+), 3 deletions(-)

diff --git a/src/video/windows/SDL_windowsevents.c b/src/video/windows/SDL_windowsevents.c
index 52e4603c9..4ee1b07de 100644
--- a/src/video/windows/SDL_windowsevents.c
+++ b/src/video/windows/SDL_windowsevents.c
@@ -497,6 +497,7 @@ WIN_WindowProc(HWND hwnd, UINT msg, WPARAM wParam, LPARAM lParam)
                 SDL_SendMouseMotion(data->window, 0, 0, cursorPos.x, cursorPos.y);
 
                 WIN_CheckAsyncMouseRelease(data);
+                WIN_UpdateClipCursor(data->window);
 
                 /*
                  * FIXME: Update keyboard state
@@ -1117,11 +1118,19 @@ static void WIN_UpdateClipCursorForWindows()
 {
     SDL_VideoDevice *_this = SDL_GetVideoDevice();
     SDL_Window *window;
+    Uint32 now = SDL_GetTicks();
+    const Uint32 CLIPCURSOR_UPDATE_INTERVAL_MS = 3000;
 
     if (_this) {
         for (window = _this->windows; window; window = window->next) {
-            if (window->driverdata) {
-                WIN_UpdateClipCursor(window);
+            SDL_WindowData *data = (SDL_WindowData *)window->driverdata;
+            if (data) {
+                if (data->skip_update_clipcursor) {
+                    data->skip_update_clipcursor = SDL_FALSE;
+                    WIN_UpdateClipCursor(window);
+                } else if ((now - data->last_updated_clipcursor) >= CLIPCURSOR_UPDATE_INTERVAL_MS) {
+                    WIN_UpdateClipCursor(window);
+                }
             }
         }
     }
diff --git a/src/video/windows/SDL_windowswindow.c b/src/video/windows/SDL_windowswindow.c
index ef73142ac..825680e44 100644
--- a/src/video/windows/SDL_windowswindow.c
+++ b/src/video/windows/SDL_windowswindow.c
@@ -34,6 +34,7 @@
 #include "SDL_windowsvideo.h"
 #include "SDL_windowswindow.h"
 #include "SDL_hints.h"
+#include "SDL_timer.h"
 
 /* Dropfile support */
 #include <shellapi.h>
@@ -926,7 +927,6 @@ WIN_UpdateClipCursor(SDL_Window *window)
         return;
     }
     if (data->skip_update_clipcursor) {
-        data->skip_update_clipcursor = SDL_FALSE;
         return;
     }
     if (!GetClipCursor(&clipped_rect)) {
@@ -969,6 +969,7 @@ WIN_UpdateClipCursor(SDL_Window *window)
         ClipCursor(NULL);
         SDL_zero(data->cursor_clipped_rect);
     }
+    data->last_updated_clipcursor = SDL_GetTicks();
 }
 
 int
diff --git a/src/video/windows/SDL_windowswindow.h b/src/video/windows/SDL_windowswindow.h
index 574a45248..cfbf12050 100644
--- a/src/video/windows/SDL_windowswindow.h
+++ b/src/video/windows/SDL_windowswindow.h
@@ -46,6 +46,7 @@ typedef struct
     SDL_bool in_title_click;
     Uint8 focus_click_pending;
     SDL_bool skip_update_clipcursor;
+    Uint32 last_updated_clipcursor;
     SDL_bool windowed_mode_was_maximized;
     SDL_bool in_window_deactivation;
     RECT cursor_clipped_rect;