Remove the behavior of warping the mouse on fullscreen transitions

This made sense when switching between a window and an exclusive fullscreen video mode of the same dimensions, but it causes user confusion when the window changes size, and doesn't work well with Wayland. I've gotten this feedback from several sources, so we'll just go ahead and remove this behavior for now.

Fixes #11577

Author: slouken

src/video/SDL_sysvideo.h

@@ -191,8 +191,7 @@ typedef enum
     VIDEO_DEVICE_CAPS_SENDS_FULLSCREEN_DIMENSIONS = 0x04,
     VIDEO_DEVICE_CAPS_FULLSCREEN_ONLY = 0x08,
     VIDEO_DEVICE_CAPS_SENDS_DISPLAY_CHANGES = 0x10,
-    VIDEO_DEVICE_CAPS_DISABLE_MOUSE_WARP_ON_FULLSCREEN_TRANSITIONS = 0x20,
-    VIDEO_DEVICE_CAPS_SENDS_HDR_CHANGES = 0x40
+    VIDEO_DEVICE_CAPS_SENDS_HDR_CHANGES = 0x20
 } DeviceCaps;
 
 // Fullscreen operations

src/video/SDL_video.c

@@ -217,11 +217,6 @@ static bool SDL_SendsDisplayChanges(SDL_VideoDevice *_this)
     return !!(_this->device_caps & VIDEO_DEVICE_CAPS_SENDS_DISPLAY_CHANGES);
 }
 
-static bool SDL_DisableMouseWarpOnFullscreenTransitions(SDL_VideoDevice *_this)
-{
-    return !!(_this->device_caps & VIDEO_DEVICE_CAPS_DISABLE_MOUSE_WARP_ON_FULLSCREEN_TRANSITIONS);
-}
-
 static bool SDL_DriverSendsHDRChanges(SDL_VideoDevice *_this)
 {
     return !!(_this->device_caps & VIDEO_DEVICE_CAPS_SENDS_HDR_CHANGES);
@@ -1876,22 +1871,6 @@ static void SDL_CheckWindowDisplayScaleChanged(SDL_Window *window)
     }
 }
 
-static void SDL_RestoreMousePosition(SDL_Window *window)
-{
-    float x, y;
-    SDL_Mouse *mouse = SDL_GetMouse();
-
-    if (window == SDL_GetMouseFocus()) {
-        const bool prev_warp_val = mouse->warp_emulation_prohibited;
-        SDL_GetMouseState(&x, &y);
-
-        // Disable the warp emulation so it isn't accidentally activated on a fullscreen transitions.
-        mouse->warp_emulation_prohibited = true;
-        SDL_WarpMouseInWindow(window, x, y);
-        mouse->warp_emulation_prohibited = prev_warp_val;
-    }
-}
-
 bool SDL_UpdateFullscreenMode(SDL_Window *window, SDL_FullscreenOp fullscreen, bool commit)
 {
     SDL_VideoDisplay *display = NULL;
@@ -2056,11 +2035,6 @@ bool SDL_UpdateFullscreenMode(SDL_Window *window, SDL_FullscreenOp fullscreen, b
                     SDL_OnWindowResized(window);
                 }
             }
-
-            // Restore the cursor position
-            if (!SDL_DisableMouseWarpOnFullscreenTransitions(_this)) {
-                SDL_RestoreMousePosition(window);
-            }
         }
     } else {
         bool resized = false;
@@ -2105,11 +2079,6 @@ bool SDL_UpdateFullscreenMode(SDL_Window *window, SDL_FullscreenOp fullscreen, b
                     SDL_OnWindowResized(window);
                 }
             }
-
-            // Restore the cursor position if we've exited fullscreen on a display
-            if (display && !SDL_DisableMouseWarpOnFullscreenTransitions(_this)) {
-                SDL_RestoreMousePosition(window);
-            }
         }
     }
 

src/video/wayland/SDL_waylandvideo.c

@@ -690,7 +690,6 @@ static SDL_VideoDevice *Wayland_CreateDevice(bool require_preferred_protocols)
                           VIDEO_DEVICE_CAPS_HAS_POPUP_WINDOW_SUPPORT |
                           VIDEO_DEVICE_CAPS_SENDS_FULLSCREEN_DIMENSIONS |
                           VIDEO_DEVICE_CAPS_SENDS_DISPLAY_CHANGES |
-                          VIDEO_DEVICE_CAPS_DISABLE_MOUSE_WARP_ON_FULLSCREEN_TRANSITIONS |
                           VIDEO_DEVICE_CAPS_SENDS_HDR_CHANGES;
 
     return device;

src/video/x11/SDL_x11video.c

@@ -263,7 +263,6 @@ static SDL_VideoDevice *X11_CreateDevice(void)
         SDL_LogInfo(SDL_LOG_CATEGORY_VIDEO, "Detected XWayland");
 
         device->device_caps |= VIDEO_DEVICE_CAPS_MODE_SWITCHING_EMULATED |
-                               VIDEO_DEVICE_CAPS_DISABLE_MOUSE_WARP_ON_FULLSCREEN_TRANSITIONS |
                                VIDEO_DEVICE_CAPS_SENDS_FULLSCREEN_DIMENSIONS;
     }