Core: Add `DisplayServer` flag for sharp corners

core/config/project_settings.cpp

@@ -1460,6 +1460,7 @@ ProjectSettings::ProjectSettings() {
 	GLOBAL_DEF("display/window/size/transparent", false);
 	GLOBAL_DEF("display/window/size/extend_to_title", false);
 	GLOBAL_DEF("display/window/size/no_focus", false);
+	GLOBAL_DEF("display/window/size/sharp_corners", false);
 
 	GLOBAL_DEF(PropertyInfo(Variant::INT, "display/window/size/window_width_override", PROPERTY_HINT_RANGE, "0,7680,1,or_greater"), 0); // 8K resolution
 	GLOBAL_DEF(PropertyInfo(Variant::INT, "display/window/size/window_height_override", PROPERTY_HINT_RANGE, "0,4320,1,or_greater"), 0); // 8K resolution

doc/classes/DisplayServer.xml

@@ -2099,7 +2099,11 @@
 		<constant name="WINDOW_FLAG_MOUSE_PASSTHROUGH" value="7" enum="WindowFlags">
 			All mouse events are passed to the underlying window of the same application.
 		</constant>
-		<constant name="WINDOW_FLAG_MAX" value="8" enum="WindowFlags">
+		<constant name="WINDOW_FLAG_SHARP_CORNERS" value="8" enum="WindowFlags">
+			Window style is overridden, forcing sharp corners.
+			[b]Note:[/b] This flag is implemented only on Windows (11).
+		</constant>
+		<constant name="WINDOW_FLAG_MAX" value="9" enum="WindowFlags">
 			Max value of the [enum WindowFlags].
 		</constant>
 		<constant name="WINDOW_EVENT_MOUSE_ENTER" value="0" enum="WindowEvent">

doc/classes/ProjectSettings.xml

@@ -875,6 +875,10 @@
 			[b]Note:[/b] Certain window managers can be configured to ignore the non-resizable status of a window. Do not rely on this setting as a guarantee that the window will [i]never[/i] be resizable.
 			[b]Note:[/b] This setting is ignored on iOS.
 		</member>
+		<member name="display/window/size/sharp_corners" type="bool" setter="" getter="" default="false">
+			If [code]true[/code], the main window uses sharp corners by default.
+			[b]Note:[/b] This property is implemented only on Windows (11).
+		</member>
 		<member name="display/window/size/transparent" type="bool" setter="" getter="" default="false">
 			If [code]true[/code], enables a window manager hint that the main window background [i]can[/i] be transparent. This does not make the background actually transparent. For the background to be transparent, the root viewport must also be made transparent by enabling [member rendering/viewport/transparent_background].
 			[b]Note:[/b] To use a transparent splash screen, set [member application/boot_splash/bg_color] to [code]Color(0, 0, 0, 0)[/code].

doc/classes/Window.xml

@@ -659,6 +659,11 @@
 			If [member ProjectSettings.display/window/subwindows/embed_subwindows] is [code]false[/code], the position is in absolute screen coordinates. This typically applies to editor plugins. If the setting is [code]true[/code], the window's position is in the coordinates of its parent [Viewport].
 			[b]Note:[/b] This property only works if [member initial_position] is set to [constant WINDOW_INITIAL_POSITION_ABSOLUTE].
 		</member>
+		<member name="sharp_corners" type="bool" setter="set_flag" getter="get_flag" default="false">
+			If [code]true[/code], the [Window] will override the OS window style to display sharp corners.
+			[b]Note:[/b] This property is implemented only on Windows (11).
+			[b]Note:[/b] This property only works with native windows.
+		</member>
 		<member name="size" type="Vector2i" setter="set_size" getter="get_size" default="Vector2i(100, 100)">
 			The window's size in pixels.
 		</member>
@@ -842,7 +847,12 @@
 			All mouse events are passed to the underlying window of the same application.
 			[b]Note:[/b] This flag has no effect in embedded windows.
 		</constant>
-		<constant name="FLAG_MAX" value="8" enum="Flags">
+		<constant name="FLAG_SHARP_CORNERS" value="8" enum="Flags">
+			Window style is overridden, forcing sharp corners.
+			[b]Note:[/b] This flag has no effect in embedded windows.
+			[b]Note:[/b] This flag is implemented only on Windows (11).
+		</constant>
+		<constant name="FLAG_MAX" value="9" enum="Flags">
 			Max value of the [enum Flags].
 		</constant>
 		<constant name="CONTENT_SCALE_MODE_DISABLED" value="0" enum="ContentScaleMode">

main/main.cpp

@@ -2412,6 +2412,9 @@ Error Main::setup(const char *execpath, int argc, char *argv[], bool p_second_ph
 		if (bool(GLOBAL_GET("display/window/size/no_focus"))) {
 			window_flags |= DisplayServer::WINDOW_FLAG_NO_FOCUS_BIT;
 		}
+		if (bool(GLOBAL_GET("display/window/size/sharp_corners"))) {
+			window_flags |= DisplayServer::WINDOW_FLAG_SHARP_CORNERS_BIT;
+		}
 		window_mode = (DisplayServer::WindowMode)(GLOBAL_GET("display/window/size/mode").operator int());
 		int initial_position_type = GLOBAL_GET("display/window/size/initial_position_type").operator int();
 		if (initial_position_type == 0) { // Absolute.

platform/windows/display_server_windows.cpp

@@ -67,6 +67,18 @@
 #define DWMWA_USE_IMMERSIVE_DARK_MODE_BEFORE_20H1 19
 #endif
 
+#ifndef DWMWA_WINDOW_CORNER_PREFERENCE
+#define DWMWA_WINDOW_CORNER_PREFERENCE 33
+#endif
+
+#ifndef DWMWCP_DEFAULT
+#define DWMWCP_DEFAULT 0
+#endif
+
+#ifndef DWMWCP_DONOTROUND
+#define DWMWCP_DONOTROUND 1
+#endif
+
 #define WM_INDICATOR_CALLBACK_MESSAGE (WM_USER + 1)
 
 #if defined(__GNUC__)
@@ -1483,6 +1495,9 @@ DisplayServer::WindowID DisplayServerWindows::create_sub_window(WindowMode p_mod
 	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_SHARP_CORNERS_BIT) {
+		wd.sharp_corners = true;
+	}
 	if (p_flags & WINDOW_FLAG_NO_FOCUS_BIT) {
 		wd.no_focus = true;
 	}
@@ -2297,6 +2312,12 @@ void DisplayServerWindows::window_set_flag(WindowFlags p_flag, bool p_enabled, W
 			wd.always_on_top = p_enabled;
 			_update_window_style(p_window);
 		} break;
+		case WINDOW_FLAG_SHARP_CORNERS: {
+			wd.sharp_corners = p_enabled;
+			DWORD value = wd.sharp_corners ? DWMWCP_DONOTROUND : DWMWCP_DEFAULT;
+			::DwmSetWindowAttribute(wd.hWnd, DWMWA_WINDOW_CORNER_PREFERENCE, &value, sizeof(value));
+			_update_window_style(p_window);
+		} break;
 		case WINDOW_FLAG_TRANSPARENT: {
 			if (p_enabled) {
 				// Enable per-pixel alpha.
@@ -3994,6 +4015,10 @@ LRESULT DisplayServerWindows::WndProc(HWND hWnd, UINT uMsg, WPARAM wParam, LPARA
 			native_menu->_menu_activate(HMENU(lParam), (int)wParam);
 		} break;
 		case WM_CREATE: {
+			{
+				DWORD value = windows[window_id].sharp_corners ? DWMWCP_DONOTROUND : DWMWCP_DEFAULT;
+				::DwmSetWindowAttribute(windows[window_id].hWnd, DWMWA_WINDOW_CORNER_PREFERENCE, &value, sizeof(value));
+			}
 			if (is_dark_mode_supported() && dark_title_available) {
 				BOOL value = is_dark_mode();
 
@@ -5645,6 +5670,12 @@ DisplayServer::WindowID DisplayServerWindows::_create_window(WindowMode p_mode,
 			wd_transient_parent->transient_children.insert(id);
 		}
 
+		wd.sharp_corners = p_flags & WINDOW_FLAG_SHARP_CORNERS_BIT;
+		{
+			DWORD value = wd.sharp_corners ? DWMWCP_DONOTROUND : DWMWCP_DEFAULT;
+			::DwmSetWindowAttribute(wd.hWnd, DWMWA_WINDOW_CORNER_PREFERENCE, &value, sizeof(value));
+		}
+
 		if (is_dark_mode_supported() && dark_title_available) {
 			BOOL value = is_dark_mode();
 			::DwmSetWindowAttribute(wd.hWnd, use_legacy_dark_mode_before_20H1 ? DWMWA_USE_IMMERSIVE_DARK_MODE_BEFORE_20H1 : DWMWA_USE_IMMERSIVE_DARK_MODE, &value, sizeof(value));

platform/windows/display_server_windows.h

@@ -473,6 +473,7 @@ class DisplayServerWindows : public DisplayServer {
 		bool exclusive = false;
 		bool context_created = false;
 		bool mpass = false;
+		bool sharp_corners = false;
 
 		// Used to transfer data between events using timer.
 		WPARAM saved_wparam;

scene/main/window.cpp

@@ -3001,6 +3001,7 @@ void Window::_bind_methods() {
 	ADD_PROPERTYI(PropertyInfo(Variant::BOOL, "popup_window"), "set_flag", "get_flag", FLAG_POPUP);
 	ADD_PROPERTYI(PropertyInfo(Variant::BOOL, "extend_to_title"), "set_flag", "get_flag", FLAG_EXTEND_TO_TITLE);
 	ADD_PROPERTYI(PropertyInfo(Variant::BOOL, "mouse_passthrough"), "set_flag", "get_flag", FLAG_MOUSE_PASSTHROUGH);
+	ADD_PROPERTYI(PropertyInfo(Variant::BOOL, "sharp_corners"), "set_flag", "get_flag", FLAG_SHARP_CORNERS);
 	ADD_PROPERTY(PropertyInfo(Variant::BOOL, "force_native"), "set_force_native", "get_force_native");
 
 	ADD_GROUP("Limits", "");
@@ -3054,6 +3055,7 @@ void Window::_bind_methods() {
 	BIND_ENUM_CONSTANT(FLAG_POPUP);
 	BIND_ENUM_CONSTANT(FLAG_EXTEND_TO_TITLE);
 	BIND_ENUM_CONSTANT(FLAG_MOUSE_PASSTHROUGH);
+	BIND_ENUM_CONSTANT(FLAG_SHARP_CORNERS);
 	BIND_ENUM_CONSTANT(FLAG_MAX);
 
 	BIND_ENUM_CONSTANT(CONTENT_SCALE_MODE_DISABLED);

scene/main/window.h

@@ -62,6 +62,7 @@ public:
 		FLAG_POPUP = DisplayServer::WINDOW_FLAG_POPUP,
 		FLAG_EXTEND_TO_TITLE = DisplayServer::WINDOW_FLAG_EXTEND_TO_TITLE,
 		FLAG_MOUSE_PASSTHROUGH = DisplayServer::WINDOW_FLAG_MOUSE_PASSTHROUGH,
+		FLAG_SHARP_CORNERS = DisplayServer::WINDOW_FLAG_SHARP_CORNERS,
 		FLAG_MAX = DisplayServer::WINDOW_FLAG_MAX,
 	};
 

servers/display_server.cpp

@@ -1128,6 +1128,7 @@ void DisplayServer::_bind_methods() {
 	BIND_ENUM_CONSTANT(WINDOW_FLAG_POPUP);
 	BIND_ENUM_CONSTANT(WINDOW_FLAG_EXTEND_TO_TITLE);
 	BIND_ENUM_CONSTANT(WINDOW_FLAG_MOUSE_PASSTHROUGH);
+	BIND_ENUM_CONSTANT(WINDOW_FLAG_SHARP_CORNERS);
 	BIND_ENUM_CONSTANT(WINDOW_FLAG_MAX);
 
 	BIND_ENUM_CONSTANT(WINDOW_EVENT_MOUSE_ENTER);

servers/display_server.h

@@ -381,6 +381,7 @@ public:
 		WINDOW_FLAG_POPUP,
 		WINDOW_FLAG_EXTEND_TO_TITLE,
 		WINDOW_FLAG_MOUSE_PASSTHROUGH,
+		WINDOW_FLAG_SHARP_CORNERS,
 		WINDOW_FLAG_MAX,
 	};
 
@@ -394,6 +395,7 @@ public:
 		WINDOW_FLAG_POPUP_BIT = (1 << WINDOW_FLAG_POPUP),
 		WINDOW_FLAG_EXTEND_TO_TITLE_BIT = (1 << WINDOW_FLAG_EXTEND_TO_TITLE),
 		WINDOW_FLAG_MOUSE_PASSTHROUGH_BIT = (1 << WINDOW_FLAG_MOUSE_PASSTHROUGH),
+		WINDOW_FLAG_SHARP_CORNERS_BIT = (1 << WINDOW_FLAG_SHARP_CORNERS),
 	};
 
 	virtual WindowID create_sub_window(WindowMode p_mode, VSyncMode p_vsync_mode, uint32_t p_flags, const Rect2i &p_rect = Rect2i(), bool p_exclusive = false, WindowID p_transient_parent = INVALID_WINDOW_ID);