Revert "Enable Vsync via Compositor by default"

This reverts commit 9600fd5dde1f85b7dd2dd8558d52ff86b18651e7.

Add comment warning about possible implications of using this option.

Fixes #35038.

core/bind/core_bind.cpp

@@ -1393,7 +1393,7 @@ void _OS::_bind_methods() {
 	ADD_PROPERTY_DEFAULT("current_screen", 0);
 	ADD_PROPERTY_DEFAULT("exit_code", 0);
 	ADD_PROPERTY_DEFAULT("vsync_enabled", true);
-	ADD_PROPERTY_DEFAULT("vsync_via_compositor", true);
+	ADD_PROPERTY_DEFAULT("vsync_via_compositor", false);
 	ADD_PROPERTY_DEFAULT("low_processor_usage_mode", false);
 	ADD_PROPERTY_DEFAULT("low_processor_usage_mode_sleep_usec", 6900);
 	ADD_PROPERTY_DEFAULT("keep_screen_on", true);

doc/classes/OS.xml

@@ -937,8 +937,9 @@
 		<member name="vsync_enabled" type="bool" setter="set_use_vsync" getter="is_vsync_enabled" default="true">
 			If [code]true[/code], vertical synchronization (Vsync) is enabled.
 		</member>
-		<member name="vsync_via_compositor" type="bool" setter="set_vsync_via_compositor" getter="is_vsync_via_compositor_enabled" default="true">
+		<member name="vsync_via_compositor" type="bool" setter="set_vsync_via_compositor" getter="is_vsync_via_compositor_enabled" default="false">
 			If [code]true[/code] and [code]vsync_enabled[/code] is true, the operating system's window compositor will be used for vsync when the compositor is enabled and the game is in windowed mode.
+			[b]Note:[/b] This option is experimental and meant to alleviate stutter experienced by some users. However, some users have experienced a Vsync framerate halving (e.g. from 60 FPS to 30 FPS) when using it.
 			[b]Note:[/b] This property is only implemented on Windows.
 		</member>
 		<member name="window_borderless" type="bool" setter="set_borderless_window" getter="get_borderless_window" default="false">

doc/classes/ProjectSettings.xml

@@ -440,8 +440,9 @@
 		<member name="display/window/vsync/use_vsync" type="bool" setter="" getter="" default="true">
 			If [code]true[/code], enables vertical synchronization. This eliminates tearing that may appear in moving scenes, at the cost of higher input latency and stuttering at lower framerates. If [code]false[/code], vertical synchronization will be disabled, however, many platforms will enforce it regardless (such as mobile platforms and HTML5).
 		</member>
-		<member name="display/window/vsync/vsync_via_compositor" type="bool" setter="" getter="" default="true">
+		<member name="display/window/vsync/vsync_via_compositor" type="bool" setter="" getter="" default="false">
 			If [code]Use Vsync[/code] is enabled and this setting is [code]true[/code], enables vertical synchronization via the operating system's window compositor when in windowed mode and the compositor is enabled. This will prevent stutter in certain situations. (Windows only.)
+			[b]Note:[/b] This option is experimental and meant to alleviate stutter experienced by some users. However, some users have experienced a Vsync framerate halving (e.g. from 60 FPS to 30 FPS) when using it.
 		</member>
 		<member name="editor/script_templates_search_path" type="String" setter="" getter="" default="&quot;res://script_templates&quot;">
 		</member>

main/main.cpp

@@ -1035,7 +1035,7 @@ Error Main::setup(const char *execpath, int argc, char *argv[], bool p_second_ph
 		// window compositor ("--enable-vsync-via-compositor" or
 		// "--disable-vsync-via-compositor") was present then it overrides the
 		// project setting.
-		video_mode.vsync_via_compositor = GLOBAL_DEF("display/window/vsync/vsync_via_compositor", true);
+		video_mode.vsync_via_compositor = GLOBAL_DEF("display/window/vsync/vsync_via_compositor", false);
 	}
 
 	OS::get_singleton()->_vsync_via_compositor = video_mode.vsync_via_compositor;