[Windows] Add WS_BORDER flag to windows in WINDOW_MODE_FULLSCREEN mode to allow multi-window interface in full-screen.

[Windows] Add WINDOW_MODE_EXCLUSIVE_FULLSCREEN without WS_BORDER flag enabled (no multi-window support).

12 files changed, 49 insertions, 13 deletions

diff --git a/doc/classes/DisplayServer.xml b/doc/classes/DisplayServer.xml
index 8be944b105..932641eb98 100644
--- a/doc/classes/DisplayServer.xml
+++ b/doc/classes/DisplayServer.xml
@@ -900,6 +900,11 @@
 			Fullscreen window mode. Note that this is not [i]exclusive[/i] fullscreen. On Windows and Linux, a borderless window is used to emulate fullscreen. On macOS, a new desktop is used to display the running project.
 			Regardless of the platform, enabling fullscreen will change the window size to match the monitor's size. Therefore, make sure your project supports [url=$DOCS_URL/tutorials/rendering/multiple_resolutions.html]multiple resolutions[/url] when enabling fullscreen mode.
 		</constant>
+		<constant name="WINDOW_MODE_EXCLUSIVE_FULLSCREEN" value="4" enum="WindowMode">
+			Exclusive fullscreen window mode. This mode is implemented on Windows only. On other platforms, it is equivalent to [constant WINDOW_MODE_FULLSCREEN].
+			Only one window in exclusive fullscreen mode can be visible on a given screen at a time. If multiple windows are in exclusive fullscreen mode for the same screen, the last one being set to this mode takes precedence.
+			Regardless of the platform, enabling fullscreen will change the window size to match the monitor's size. Therefore, make sure your project supports [url=$DOCS_URL/tutorials/rendering/multiple_resolutions.html]multiple resolutions[/url] when enabling fullscreen mode.
+		</constant>
 		<constant name="WINDOW_FLAG_RESIZE_DISABLED" value="0" enum="WindowFlags">
 		</constant>
 		<constant name="WINDOW_FLAG_BORDERLESS" value="1" enum="WindowFlags">
diff --git a/doc/classes/Window.xml b/doc/classes/Window.xml
index 3bb6603646..ab8f51ced5 100644
--- a/doc/classes/Window.xml
+++ b/doc/classes/Window.xml
@@ -398,6 +398,11 @@
 			Fullscreen window mode. Note that this is not [i]exclusive[/i] fullscreen. On Windows and Linux, a borderless window is used to emulate fullscreen. On macOS, a new desktop is used to display the running project.
 			Regardless of the platform, enabling fullscreen will change the window size to match the monitor's size. Therefore, make sure your project supports [url=$DOCS_URL/tutorials/rendering/multiple_resolutions.html]multiple resolutions[/url] when enabling fullscreen mode.
 		</constant>
+		<constant name="MODE_EXCLUSIVE_FULLSCREEN" value="4" enum="Mode">
+			Exclusive fullscreen window mode. This mode is implemented on Windows only. On other platforms, it is equivalent to [constant MODE_FULLSCREEN].
+			Only one window in exclusive fullscreen mode can be visible on a given screen at a time. If multiple windows are in exclusive fullscreen mode for the same screen, the last one being set to this mode takes precedence.
+			Regardless of the platform, enabling fullscreen will change the window size to match the monitor's size. Therefore, make sure your project supports [url=$DOCS_URL/tutorials/rendering/multiple_resolutions.html]multiple resolutions[/url] when enabling fullscreen mode.
+		</constant>
 		<constant name="FLAG_RESIZE_DISABLED" value="0" enum="Flags">
 			The window's ability to be resized.
 		</constant>
diff --git a/platform/javascript/display_server_javascript.cpp b/platform/javascript/display_server_javascript.cpp
index 2842fc2f5e..fb7f0b5dfa 100644
--- a/platform/javascript/display_server_javascript.cpp
+++ b/platform/javascript/display_server_javascript.cpp
@@ -663,7 +663,7 @@ DisplayServerJavaScript::DisplayServerJavaScript(const String &p_rendering_drive
 	godot_js_config_canvas_id_get(canvas_id, 256);
 
 	// Handle contextmenu, webglcontextlost
-	godot_js_display_setup_canvas(p_resolution.x, p_resolution.y, p_window_mode == WINDOW_MODE_FULLSCREEN, OS::get_singleton()->is_hidpi_allowed() ? 1 : 0);
+	godot_js_display_setup_canvas(p_resolution.x, p_resolution.y, (p_window_mode == WINDOW_MODE_FULLSCREEN || p_window_mode == WINDOW_MODE_EXCLUSIVE_FULLSCREEN), OS::get_singleton()->is_hidpi_allowed() ? 1 : 0);
 
 	// Check if it's windows.
 	swap_cancel_ok = godot_js_display_is_swap_ok_cancel() == 1;
@@ -897,6 +897,7 @@ void DisplayServerJavaScript::window_set_mode(WindowMode p_mode, WindowID p_wind
 			}
 			window_mode = WINDOW_MODE_WINDOWED;
 		} break;
+		case WINDOW_MODE_EXCLUSIVE_FULLSCREEN:
 		case WINDOW_MODE_FULLSCREEN: {
 			int result = godot_js_display_fullscreen_request();
 			ERR_FAIL_COND_MSG(result, "The request was denied. Remember that enabling fullscreen is only possible from an input callback for the HTML5 platform.");
diff --git a/platform/linuxbsd/display_server_x11.cpp b/platform/linuxbsd/display_server_x11.cpp
index 198eacd1f3..021dfe2399 100644
--- a/platform/linuxbsd/display_server_x11.cpp
+++ b/platform/linuxbsd/display_server_x11.cpp
@@ -1825,6 +1825,7 @@ void DisplayServerX11::window_set_mode(WindowMode p_mode, WindowID p_window) {
 
 			XSendEvent(x11_display, DefaultRootWindow(x11_display), False, SubstructureRedirectMask | SubstructureNotifyMask, &xev);
 		} break;
+		case WINDOW_MODE_EXCLUSIVE_FULLSCREEN:
 		case WINDOW_MODE_FULLSCREEN: {
 			//Remove full-screen
 			wd.fullscreen = false;
@@ -1877,6 +1878,7 @@ void DisplayServerX11::window_set_mode(WindowMode p_mode, WindowID p_window) {
 
 			XSendEvent(x11_display, DefaultRootWindow(x11_display), False, SubstructureRedirectMask | SubstructureNotifyMask, &xev);
 		} break;
+		case WINDOW_MODE_EXCLUSIVE_FULLSCREEN:
 		case WINDOW_MODE_FULLSCREEN: {
 			wd.last_position_before_fs = wd.position;
 
diff --git a/platform/osx/display_server_osx.mm b/platform/osx/display_server_osx.mm
index f7add5b688..d116a73ed3 100644
--- a/platform/osx/display_server_osx.mm
+++ b/platform/osx/display_server_osx.mm
@@ -2652,6 +2652,7 @@ void DisplayServerOSX::window_set_mode(WindowMode p_mode, WindowID p_window) {
 		case WINDOW_MODE_MINIMIZED: {
 			[wd.window_object deminiaturize:nil];
 		} break;
+		case WINDOW_MODE_EXCLUSIVE_FULLSCREEN:
 		case WINDOW_MODE_FULLSCREEN: {
 			[wd.window_object setLevel:NSNormalWindowLevel];
 			if (wd.layered_window) {
@@ -2685,6 +2686,7 @@ void DisplayServerOSX::window_set_mode(WindowMode p_mode, WindowID p_window) {
 		case WINDOW_MODE_MINIMIZED: {
 			[wd.window_object performMiniaturize:nil];
 		} break;
+		case WINDOW_MODE_EXCLUSIVE_FULLSCREEN:
 		case WINDOW_MODE_FULLSCREEN: {
 			if (wd.layered_window)
 				_set_window_per_pixel_transparency_enabled(false, p_window);
diff --git a/platform/windows/display_server_windows.cpp b/platform/windows/display_server_windows.cpp
index d288c27016..bf1d209854 100644
--- a/platform/windows/display_server_windows.cpp
+++ b/platform/windows/display_server_windows.cpp
@@ -506,7 +506,7 @@ DisplayServer::WindowID DisplayServerWindows::create_sub_window(WindowMode p_mod
 	if (p_flags & WINDOW_FLAG_BORDERLESS_BIT) {
 		wd.borderless = true;
 	}
-	if (p_flags & WINDOW_FLAG_ALWAYS_ON_TOP_BIT && p_mode != WINDOW_MODE_FULLSCREEN) {
+	if (p_flags & WINDOW_FLAG_ALWAYS_ON_TOP_BIT && p_mode != WINDOW_MODE_FULLSCREEN && p_mode != WINDOW_MODE_EXCLUSIVE_FULLSCREEN) {
 		wd.always_on_top = true;
 	}
 	if (p_flags & WINDOW_FLAG_NO_FOCUS_BIT) {
@@ -946,7 +946,7 @@ Size2i DisplayServerWindows::window_get_real_size(WindowID p_window) const {
 	return Size2();
 }
 
-void DisplayServerWindows::_get_window_style(bool p_main_window, bool p_fullscreen, bool p_borderless, bool p_resizable, bool p_maximized, bool p_no_activate_focus, DWORD &r_style, DWORD &r_style_ex) {
+void DisplayServerWindows::_get_window_style(bool p_main_window, bool p_fullscreen, bool p_multiwindow_fs, bool p_borderless, bool p_resizable, bool p_maximized, bool p_no_activate_focus, DWORD &r_style, DWORD &r_style_ex) {
 	// Windows docs for window styles:
 	// https://docs.microsoft.com/en-us/windows/win32/winmsg/window-styles
 	// https://docs.microsoft.com/en-us/windows/win32/winmsg/extended-window-styles
@@ -959,6 +959,9 @@ void DisplayServerWindows::_get_window_style(bool p_main_window, bool p_fullscre
 
 	if (p_fullscreen || p_borderless) {
 		r_style |= WS_POPUP; // p_borderless was WS_EX_TOOLWINDOW in the past.
+		if (p_fullscreen && p_multiwindow_fs) {
+			r_style |= WS_BORDER; // Allows child windows to be displayed on top of full screen.
+		}
 	} else {
 		if (p_resizable) {
 			if (p_maximized) {
@@ -989,7 +992,7 @@ void DisplayServerWindows::_update_window_style(WindowID p_window, bool p_repain
 	DWORD style = 0;
 	DWORD style_ex = 0;
 
-	_get_window_style(p_window == MAIN_WINDOW_ID, wd.fullscreen, wd.borderless, wd.resizable, wd.maximized, wd.no_focus, style, style_ex);
+	_get_window_style(p_window == MAIN_WINDOW_ID, wd.fullscreen, wd.multiwindow_fs, wd.borderless, wd.resizable, wd.maximized, wd.no_focus, style, style_ex);
 
 	SetWindowLongPtr(wd.hWnd, GWL_STYLE, style);
 	SetWindowLongPtr(wd.hWnd, GWL_EXSTYLE, style_ex);
@@ -1009,10 +1012,11 @@ void DisplayServerWindows::window_set_mode(WindowMode p_mode, WindowID p_window)
 	ERR_FAIL_COND(!windows.has(p_window));
 	WindowData &wd = windows[p_window];
 
-	if (wd.fullscreen && p_mode != WINDOW_MODE_FULLSCREEN) {
+	if (wd.fullscreen && p_mode != WINDOW_MODE_FULLSCREEN && p_mode != WINDOW_MODE_EXCLUSIVE_FULLSCREEN) {
 		RECT rect;
 
 		wd.fullscreen = false;
+		wd.multiwindow_fs = false;
 		wd.maximized = wd.was_maximized;
 
 		if (wd.pre_fs_valid) {
@@ -1051,7 +1055,15 @@ void DisplayServerWindows::window_set_mode(WindowMode p_mode, WindowID p_window)
 		wd.minimized = true;
 	}
 
-	if (p_mode == WINDOW_MODE_FULLSCREEN && !wd.fullscreen) {
+	if (p_mode == WINDOW_MODE_EXCLUSIVE_FULLSCREEN) {
+		wd.multiwindow_fs = false;
+		_update_window_style(false);
+	} else {
+		wd.multiwindow_fs = true;
+		_update_window_style(false);
+	}
+
+	if ((p_mode == WINDOW_MODE_FULLSCREEN || p_mode == WINDOW_MODE_EXCLUSIVE_FULLSCREEN) && !wd.fullscreen) {
 		if (wd.minimized) {
 			ShowWindow(wd.hWnd, SW_RESTORE);
 		}
@@ -1098,7 +1110,11 @@ DisplayServer::WindowMode DisplayServerWindows::window_get_mode(WindowID p_windo
 	const WindowData &wd = windows[p_window];
 
 	if (wd.fullscreen) {
-		return WINDOW_MODE_FULLSCREEN;
+		if (wd.multiwindow_fs) {
+			return WINDOW_MODE_FULLSCREEN;
+		} else {
+			return WINDOW_MODE_EXCLUSIVE_FULLSCREEN;
+		}
 	} else if (wd.minimized) {
 		return WINDOW_MODE_MINIMIZED;
 	} else if (wd.maximized) {
@@ -3088,7 +3104,7 @@ DisplayServer::WindowID DisplayServerWindows::_create_window(WindowMode p_mode,
 	DWORD dwExStyle;
 	DWORD dwStyle;
 
-	_get_window_style(window_id_counter == MAIN_WINDOW_ID, p_mode == WINDOW_MODE_FULLSCREEN, p_flags & WINDOW_FLAG_BORDERLESS_BIT, !(p_flags & WINDOW_FLAG_RESIZE_DISABLED_BIT), p_mode == WINDOW_MODE_MAXIMIZED, (p_flags & WINDOW_FLAG_NO_FOCUS_BIT), dwStyle, dwExStyle);
+	_get_window_style(window_id_counter == MAIN_WINDOW_ID, (p_mode == WINDOW_MODE_FULLSCREEN || p_mode == WINDOW_MODE_EXCLUSIVE_FULLSCREEN), p_mode == WINDOW_MODE_EXCLUSIVE_FULLSCREEN, p_flags & WINDOW_FLAG_BORDERLESS_BIT, !(p_flags & WINDOW_FLAG_RESIZE_DISABLED_BIT), p_mode == WINDOW_MODE_MAXIMIZED, (p_flags & WINDOW_FLAG_NO_FOCUS_BIT), dwStyle, dwExStyle);
 
 	RECT WindowRect;
 
@@ -3097,7 +3113,7 @@ DisplayServer::WindowID DisplayServerWindows::_create_window(WindowMode p_mode,
 	WindowRect.top = p_rect.position.y;
 	WindowRect.bottom = p_rect.position.y + p_rect.size.y;
 
-	if (p_mode == WINDOW_MODE_FULLSCREEN) {
+	if (p_mode == WINDOW_MODE_FULLSCREEN || p_mode == WINDOW_MODE_EXCLUSIVE_FULLSCREEN) {
 		int nearest_area = 0;
 		Rect2i screen_rect;
 		for (int i = 0; i < get_screen_count(); i++) {
@@ -3140,7 +3156,7 @@ DisplayServer::WindowID DisplayServerWindows::_create_window(WindowMode p_mode,
 			windows.erase(id);
 			return INVALID_WINDOW_ID;
 		}
-		if (p_mode != WINDOW_MODE_FULLSCREEN) {
+		if (p_mode != WINDOW_MODE_FULLSCREEN && p_mode != WINDOW_MODE_EXCLUSIVE_FULLSCREEN) {
 			wd.pre_fs_valid = true;
 		}
 
diff --git a/platform/windows/display_server_windows.h b/platform/windows/display_server_windows.h
index 803c2d4836..3f6275a49e 100644
--- a/platform/windows/display_server_windows.h
+++ b/platform/windows/display_server_windows.h
@@ -332,6 +332,7 @@ class DisplayServerWindows : public DisplayServer {
 		bool maximized = false;
 		bool minimized = false;
 		bool fullscreen = false;
+		bool multiwindow_fs = false;
 		bool borderless = false;
 		bool resizable = true;
 		bool window_focused = false;
@@ -401,7 +402,7 @@ class DisplayServerWindows : public DisplayServer {
 	WNDPROC user_proc = nullptr;
 
 	void _send_window_event(const WindowData &wd, WindowEvent p_event);
-	void _get_window_style(bool p_main_window, bool p_fullscreen, bool p_borderless, bool p_resizable, bool p_maximized, bool p_no_activate_focus, DWORD &r_style, DWORD &r_style_ex);
+	void _get_window_style(bool p_main_window, bool p_fullscreen, bool p_multiwindow_fs, bool p_borderless, bool p_resizable, bool p_maximized, bool p_no_activate_focus, DWORD &r_style, DWORD &r_style_ex);
 
 	MouseMode mouse_mode;
 	int restore_mouse_trails = 0;
diff --git a/scene/main/viewport.cpp b/scene/main/viewport.cpp
index 09880ad6cf..522997cdf5 100644
--- a/scene/main/viewport.cpp
+++ b/scene/main/viewport.cpp
@@ -1231,7 +1231,7 @@ void Viewport::_gui_show_tooltip() {
 
 	base_tooltip->set_anchors_and_offsets_preset(Control::PRESET_WIDE);
 
-	panel->set_transient(false);
+	panel->set_transient(true);
 	panel->set_flag(Window::FLAG_NO_FOCUS, true);
 	panel->set_wrap_controls(true);
 	panel->add_child(base_tooltip);
diff --git a/scene/main/window.cpp b/scene/main/window.cpp
index fbc0bc5301..f2ebe50fa3 100644
--- a/scene/main/window.cpp
+++ b/scene/main/window.cpp
@@ -1614,6 +1614,7 @@ void Window::_bind_methods() {
 	BIND_ENUM_CONSTANT(MODE_MINIMIZED);
 	BIND_ENUM_CONSTANT(MODE_MAXIMIZED);
 	BIND_ENUM_CONSTANT(MODE_FULLSCREEN);
+	BIND_ENUM_CONSTANT(MODE_EXCLUSIVE_FULLSCREEN);
 
 	BIND_ENUM_CONSTANT(FLAG_RESIZE_DISABLED);
 	BIND_ENUM_CONSTANT(FLAG_BORDERLESS);
diff --git a/scene/main/window.h b/scene/main/window.h
index 2dd1dd6601..f37689f905 100644
--- a/scene/main/window.h
+++ b/scene/main/window.h
@@ -46,6 +46,7 @@ public:
 		MODE_MINIMIZED = DisplayServer::WINDOW_MODE_MINIMIZED,
 		MODE_MAXIMIZED = DisplayServer::WINDOW_MODE_MAXIMIZED,
 		MODE_FULLSCREEN = DisplayServer::WINDOW_MODE_FULLSCREEN,
+		MODE_EXCLUSIVE_FULLSCREEN = DisplayServer::WINDOW_MODE_EXCLUSIVE_FULLSCREEN,
 	};
 
 	enum Flags {
diff --git a/servers/display_server.cpp b/servers/display_server.cpp
index 5ded5cf214..f6ba14f0fe 100644
--- a/servers/display_server.cpp
+++ b/servers/display_server.cpp
@@ -539,6 +539,7 @@ void DisplayServer::_bind_methods() {
 	BIND_ENUM_CONSTANT(WINDOW_MODE_MINIMIZED);
 	BIND_ENUM_CONSTANT(WINDOW_MODE_MAXIMIZED);
 	BIND_ENUM_CONSTANT(WINDOW_MODE_FULLSCREEN);
+	BIND_ENUM_CONSTANT(WINDOW_MODE_EXCLUSIVE_FULLSCREEN);
 
 	BIND_ENUM_CONSTANT(WINDOW_FLAG_RESIZE_DISABLED);
 	BIND_ENUM_CONSTANT(WINDOW_FLAG_BORDERLESS);
diff --git a/servers/display_server.h b/servers/display_server.h
index 8c6586dc20..20f939921a 100644
--- a/servers/display_server.h
+++ b/servers/display_server.h
@@ -53,7 +53,8 @@ public:
 		WINDOW_MODE_WINDOWED,
 		WINDOW_MODE_MINIMIZED,
 		WINDOW_MODE_MAXIMIZED,
-		WINDOW_MODE_FULLSCREEN
+		WINDOW_MODE_FULLSCREEN,
+		WINDOW_MODE_EXCLUSIVE_FULLSCREEN,
 	};
 
 	// Keep the VSyncMode enum values in sync with the `display/window/vsync/vsync_mode`