From 6c962177272c6a2ce684e4298b40c25ebdd1ac74 Mon Sep 17 00:00:00 2001
From: Sam Lantinga <[EMAIL REDACTED]>
Date: Fri, 18 Mar 2022 10:07:59 -0700
Subject: [PATCH] Added the hint SDL_HINT_MOUSE_RELATIVE_MODE_CENTER,
controlling whether the mouse should be constrained to the center of the
window or the whole window in relative mode.
For further info about the pros and cons, check out the discussion in https://github.com/libsdl-org/SDL/issues/5271
---
include/SDL_hints.h | 16 ++++++
src/video/windows/SDL_windowswindow.c | 73 ++++++++++++++++-----------
src/video/windows/SDL_windowswindow.h | 1 +
3 files changed, 61 insertions(+), 29 deletions(-)
diff --git a/include/SDL_hints.h b/include/SDL_hints.h
index 25383b1a72a..140d37d7fae 100644
--- a/include/SDL_hints.h
+++ b/include/SDL_hints.h
@@ -933,6 +933,22 @@ extern "C" {
*/
#define SDL_HINT_MOUSE_NORMAL_SPEED_SCALE "SDL_MOUSE_NORMAL_SPEED_SCALE"
+/**
+ * \brief A variable controlling whether relative mouse mode constrains the mouse to the center of the window
+ *
+ * This variable can be set to the following values:
+ * "0" - Relative mouse mode constrains the mouse to the window
+ * "1" - Relative mouse mode constrains the mouse to the center of the window
+ *
+ * Constraining to the center of the window works better for FPS games and when the
+ * application is running over RDP. Constraining to the whole window works better
+ * for 2D games and increases the chance that the mouse will be in the correct
+ * position when using high DPI mice.
+ *
+ * By default SDL will constrain the mouse to the center of the window
+ */
+#define SDL_HINT_MOUSE_RELATIVE_MODE_CENTER "SDL_MOUSE_RELATIVE_MODE_CENTER"
+
/**
* \brief A variable controlling whether relative mouse mode is implemented using mouse warping
*
diff --git a/src/video/windows/SDL_windowswindow.c b/src/video/windows/SDL_windowswindow.c
index ccf4920251e..890d790eab0 100644
--- a/src/video/windows/SDL_windowswindow.c
+++ b/src/video/windows/SDL_windowswindow.c
@@ -28,6 +28,7 @@
#include "../SDL_pixels_c.h"
#include "../../events/SDL_keyboard_c.h"
#include "../../events/SDL_mouse_c.h"
+#include "../../SDL_hints_c.h"
#include "SDL_windowsvideo.h"
#include "SDL_windowswindow.h"
@@ -170,6 +171,13 @@ WIN_SetWindowPositionInternal(_THIS, SDL_Window * window, UINT flags)
data->expected_resize = SDL_FALSE;
}
+static void SDLCALL
+WIN_MouseRelativeModeCenterChanged(void *userdata, const char *name, const char *oldValue, const char *hint)
+{
+ SDL_WindowData *data = (SDL_WindowData *)userdata;
+ data->mouse_relative_mode_center = SDL_GetStringBoolean(hint, SDL_TRUE);
+}
+
static int
SetupWindowData(_THIS, SDL_Window * window, HWND hwnd, HWND parent, SDL_bool created)
{
@@ -193,6 +201,8 @@ SetupWindowData(_THIS, SDL_Window * window, HWND hwnd, HWND parent, SDL_bool cre
data->videodata = videodata;
data->initializing = SDL_TRUE;
+ SDL_AddHintCallback(SDL_HINT_MOUSE_RELATIVE_MODE_CENTER, WIN_MouseRelativeModeCenterChanged, data);
+
window->driverdata = data;
/* Associate the data with the window */
@@ -297,7 +307,39 @@ SetupWindowData(_THIS, SDL_Window * window, HWND hwnd, HWND parent, SDL_bool cre
return 0;
}
+static void CleanupWindowData(_THIS, SDL_Window * window)
+{
+ SDL_WindowData *data = (SDL_WindowData *) window->driverdata;
+
+ if (data) {
+ SDL_DelHintCallback(SDL_HINT_MOUSE_RELATIVE_MODE_CENTER, WIN_MouseRelativeModeCenterChanged, data);
+ if (data->keyboard_hook) {
+ UnhookWindowsHookEx(data->keyboard_hook);
+ }
+ ReleaseDC(data->hwnd, data->hdc);
+ RemoveProp(data->hwnd, TEXT("SDL_WindowData"));
+ if (data->created) {
+ DestroyWindow(data->hwnd);
+ if (data->parent) {
+ DestroyWindow(data->parent);
+ }
+ } else {
+ /* Restore any original event handler... */
+ if (data->wndproc != NULL) {
+#ifdef GWLP_WNDPROC
+ SetWindowLongPtr(data->hwnd, GWLP_WNDPROC,
+ (LONG_PTR) data->wndproc);
+#else
+ SetWindowLong(data->hwnd, GWL_WNDPROC,
+ (LONG_PTR) data->wndproc);
+#endif
+ }
+ }
+ SDL_free(data);
+ }
+ window->driverdata = NULL;
+}
int
WIN_CreateWindow(_THIS, SDL_Window * window)
@@ -873,34 +915,7 @@ WIN_SetWindowKeyboardGrab(_THIS, SDL_Window * window, SDL_bool grabbed)
void
WIN_DestroyWindow(_THIS, SDL_Window * window)
{
- SDL_WindowData *data = (SDL_WindowData *) window->driverdata;
-
- if (data) {
- if (data->keyboard_hook) {
- UnhookWindowsHookEx(data->keyboard_hook);
- }
- ReleaseDC(data->hwnd, data->hdc);
- RemoveProp(data->hwnd, TEXT("SDL_WindowData"));
- if (data->created) {
- DestroyWindow(data->hwnd);
- if (data->parent) {
- DestroyWindow(data->parent);
- }
- } else {
- /* Restore any original event handler... */
- if (data->wndproc != NULL) {
-#ifdef GWLP_WNDPROC
- SetWindowLongPtr(data->hwnd, GWLP_WNDPROC,
- (LONG_PTR) data->wndproc);
-#else
- SetWindowLong(data->hwnd, GWL_WNDPROC,
- (LONG_PTR) data->wndproc);
-#endif
- }
- }
- SDL_free(data);
- }
- window->driverdata = NULL;
+ CleanupWindowData(_this, window);
}
SDL_bool
@@ -1032,7 +1047,7 @@ WIN_UpdateClipCursor(SDL_Window *window)
if ((mouse->relative_mode || (window->flags & SDL_WINDOW_MOUSE_GRABBED) ||
(window->mouse_rect.w > 0 && window->mouse_rect.h > 0)) &&
(window->flags & SDL_WINDOW_INPUT_FOCUS)) {
- if (mouse->relative_mode && !mouse->relative_mode_warp) {
+ if (mouse->relative_mode && !mouse->relative_mode_warp && data->mouse_relative_mode_center) {
if (GetWindowRect(data->hwnd, &rect)) {
LONG cx, cy;
diff --git a/src/video/windows/SDL_windowswindow.h b/src/video/windows/SDL_windowswindow.h
index d1570fdb05d..659366a9fb1 100644
--- a/src/video/windows/SDL_windowswindow.h
+++ b/src/video/windows/SDL_windowswindow.h
@@ -49,6 +49,7 @@ typedef struct
Uint8 focus_click_pending;
SDL_bool skip_update_clipcursor;
Uint32 last_updated_clipcursor;
+ SDL_bool mouse_relative_mode_center;
SDL_bool windowed_mode_was_maximized;
SDL_bool in_window_deactivation;
RECT cursor_clipped_rect;