From a45ef5dc6443e2ebcfc085b10b4ea4a3d145ea63 Mon Sep 17 00:00:00 2001
From: Sam Lantinga <slouken@libsdl.org>
Date: Mon, 22 Jun 2026 20:33:27 -0700
Subject: [PATCH] Added RIDEV_NOLEGACY to improve performance in mouse relative
 mode (thanks @whrvt!)

This change also makes it so relative mode doesn't kick in until the mouse enters the window client area. This prevents relative mode from kicking in while clicking and dragging on the title bar, etc.
---
 src/events/SDL_mouse.c                  | 8 +++++++-
 src/video/SDL_video.c                   | 2 ++
 src/video/windows/SDL_windowsrawinput.c | 2 +-
 3 files changed, 10 insertions(+), 2 deletions(-)

diff --git a/src/events/SDL_mouse.c b/src/events/SDL_mouse.c
index db622399c1..62cfb362d6 100644
--- a/src/events/SDL_mouse.c
+++ b/src/events/SDL_mouse.c
@@ -1419,7 +1419,13 @@ bool SDL_UpdateRelativeMouseMode(void)
 {
     SDL_Mouse *mouse = SDL_GetMouse();
     SDL_Window *focus = SDL_GetKeyboardFocus();
-    bool relative_mode = (focus && (focus->flags & SDL_WINDOW_MOUSE_RELATIVE_MODE));
+    bool relative_mode = false;
+
+    if (focus &&
+        (focus->flags & SDL_WINDOW_MOUSE_RELATIVE_MODE) &&
+        (focus->flags & SDL_WINDOW_MOUSE_FOCUS)) {
+        relative_mode = true;
+    }
 
     if (relative_mode == mouse->relative_mode) {
         return true;
diff --git a/src/video/SDL_video.c b/src/video/SDL_video.c
index aed81189e3..c99e45216a 100644
--- a/src/video/SDL_video.c
+++ b/src/video/SDL_video.c
@@ -4416,10 +4416,12 @@ void SDL_OnWindowEnter(SDL_Window *window)
     if (_this->OnWindowEnter) {
         _this->OnWindowEnter(_this, window);
     }
+    SDL_UpdateRelativeMouseMode();
 }
 
 void SDL_OnWindowLeave(SDL_Window *window)
 {
+    SDL_UpdateRelativeMouseMode();
 }
 
 void SDL_OnWindowFocusGained(SDL_Window *window)
diff --git a/src/video/windows/SDL_windowsrawinput.c b/src/video/windows/SDL_windowsrawinput.c
index 497e8007bc..c5f193c73f 100644
--- a/src/video/windows/SDL_windowsrawinput.c
+++ b/src/video/windows/SDL_windowsrawinput.c
@@ -98,7 +98,7 @@ static bool UpdateRawInputDeviceFlags(HWND window, Uint32 last_flags, Uint32 new
         devices[count].usUsage = USB_USAGE_GENERIC_MOUSE;
 
         if (new_flags & ENABLE_RAW_MOUSE_INPUT) {
-            devices[count].dwFlags = 0;
+            devices[count].dwFlags = RIDEV_NOLEGACY;
             devices[count].hwndTarget = window;
         } else {
             devices[count].dwFlags = RIDEV_REMOVE;