Add activate_feed and deactivate_feed virtual bind to CameraFeed

doc/classes/CameraFeed.xml

@@ -10,6 +10,18 @@
 	<tutorials>
 	</tutorials>
 	<methods>
+		<method name="_activate_feed" qualifiers="virtual">
+			<return type="bool" />
+			<description>
+				Called when the camera feed is activated.
+			</description>
+		</method>
+		<method name="_deactivate_feed" qualifiers="virtual">
+			<return type="void" />
+			<description>
+				Called when the camera feed is deactivated.
+			</description>
+		</method>
 		<method name="get_datatype" qualifiers="const">
 			<return type="int" enum="CameraFeed.FeedDataType" />
 			<description>

servers/camera/camera_feed.cpp

@@ -58,6 +58,9 @@ void CameraFeed::_bind_methods() {
 	ClassDB::bind_method(D_METHOD("get_formats"), &CameraFeed::get_formats);
 	ClassDB::bind_method(D_METHOD("set_format", "index", "parameters"), &CameraFeed::set_format);
 
+	GDVIRTUAL_BIND(_activate_feed);
+	GDVIRTUAL_BIND(_deactivate_feed);
+
 	ADD_SIGNAL(MethodInfo("frame_changed"));
 	ADD_SIGNAL(MethodInfo("format_changed"));
 
@@ -273,12 +276,13 @@ void CameraFeed::set_external(int p_width, int p_height) {
 }
 
 bool CameraFeed::activate_feed() {
-	// nothing to do here
-	return true;
+	bool ret = true;
+	GDVIRTUAL_CALL(_activate_feed, ret);
+	return ret;
 }
 
 void CameraFeed::deactivate_feed() {
-	// nothing to do here
+	GDVIRTUAL_CALL(_deactivate_feed);
 }
 
 bool CameraFeed::set_format(int p_index, const Dictionary &p_parameters) {

servers/camera/camera_feed.h

@@ -123,6 +123,9 @@ public:
 
 	virtual bool activate_feed();
 	virtual void deactivate_feed();
+
+	GDVIRTUAL0R(bool, _activate_feed)
+	GDVIRTUAL0(_deactivate_feed)
 };
 
 VARIANT_ENUM_CAST(CameraFeed::FeedDataType);