Rename the physics server `run_on_thread` project settings

`run_on_separate_thread` is more explicit.

core/config/project_settings.cpp

@@ -1235,8 +1235,8 @@ ProjectSettings::ProjectSettings() {
 	// Keep the enum values in sync with the `DisplayServer::VSyncMode` enum.
 	custom_prop_info["display/window/vsync/vsync_mode"] = PropertyInfo(Variant::INT, "display/window/vsync/vsync_mode", PROPERTY_HINT_ENUM, "Disabled,Enabled,Adaptive,Mailbox");
 	custom_prop_info["rendering/driver/threads/thread_model"] = PropertyInfo(Variant::INT, "rendering/driver/threads/thread_model", PROPERTY_HINT_ENUM, "Single-Unsafe,Single-Safe,Multi-Threaded");
-	GLOBAL_DEF("physics/2d/run_on_thread", false);
-	GLOBAL_DEF("physics/3d/run_on_thread", false);
+	GLOBAL_DEF("physics/2d/run_on_separate_thread", false);
+	GLOBAL_DEF("physics/3d/run_on_separate_thread", false);
 
 	GLOBAL_DEF("debug/settings/profiler/max_functions", 16384);
 	custom_prop_info["debug/settings/profiler/max_functions"] = PropertyInfo(Variant::INT, "debug/settings/profiler/max_functions", PROPERTY_HINT_RANGE, "128,65535,1");

doc/classes/ProjectSettings.xml

@@ -1412,8 +1412,8 @@
 			Sets which physics engine to use for 2D physics.
 			"DEFAULT" and "GodotPhysics2D" are the same, as there is currently no alternative 2D physics server implemented.
 		</member>
-		<member name="physics/2d/run_on_thread" type="bool" setter="" getter="" default="false">
-			Sets whether 2D physics is run on the main thread or a separate one. Running the server on a thread increases performance, but restricts API access to only physics process.
+		<member name="physics/2d/run_on_separate_thread" type="bool" setter="" getter="" default="false">
+			If [code]true[/code], the 2D physics server runs on a separate thread, making better use of multi-core CPUs. If [code]false[/code], the 2D physics server runs on the main thread. Running the physics server on a separate thread can increase performance, but restricts API access to only physics process.
 		</member>
 		<member name="physics/2d/sleep_threshold_angular" type="float" setter="" getter="" default="0.139626">
 			Threshold angular velocity under which a 2D physics body will be considered inactive. See [constant PhysicsServer2D.SPACE_PARAM_BODY_ANGULAR_VELOCITY_SLEEP_THRESHOLD].
@@ -1484,8 +1484,8 @@
 			Sets which physics engine to use for 3D physics.
 			"DEFAULT" is currently the [url=https://bulletphysics.org]Bullet[/url] physics engine. The "GodotPhysics3D" engine is still supported as an alternative.
 		</member>
-		<member name="physics/3d/run_on_thread" type="bool" setter="" getter="" default="false">
-			Sets whether 3D physics is run on the main thread or a separate one. Running the server on a thread increases performance, but restricts API access to only physics process.
+		<member name="physics/3d/run_on_separate_thread" type="bool" setter="" getter="" default="false">
+			If [code]true[/code], the 3D physics server runs on a separate thread, making better use of multi-core CPUs. If [code]false[/code], the 3D physics server runs on the main thread. Running the physics server on a separate thread can increase performance, but restricts API access to only physics process.
 		</member>
 		<member name="physics/3d/sleep_threshold_angular" type="float" setter="" getter="" default="0.139626">
 			Threshold angular velocity under which a 3D physics body will be considered inactive. See [constant PhysicsServer3D.SPACE_PARAM_BODY_ANGULAR_VELOCITY_SLEEP_THRESHOLD].

servers/register_server_types.cpp

@@ -80,7 +80,7 @@
 ShaderTypes *shader_types = nullptr;
 
 PhysicsServer3D *_createGodotPhysics3DCallback() {
-	bool using_threads = GLOBAL_GET("physics/3d/run_on_thread");
+	bool using_threads = GLOBAL_GET("physics/3d/run_on_separate_thread");
 
 	PhysicsServer3D *physics_server = memnew(GodotPhysicsServer3D(using_threads));
 
@@ -88,7 +88,7 @@ PhysicsServer3D *_createGodotPhysics3DCallback() {
 }
 
 PhysicsServer2D *_createGodotPhysics2DCallback() {
-	bool using_threads = GLOBAL_GET("physics/2d/run_on_thread");
+	bool using_threads = GLOBAL_GET("physics/2d/run_on_separate_thread");
 
 	PhysicsServer2D *physics_server = memnew(GodotPhysicsServer2D(using_threads));