Change name of update_animation function

I will use this for sounds, and so it needs to be changed to a more general name

1 files changed, 4 insertions, 3 deletions

diff --git a/advtrains/api_doc.txt b/advtrains/api_doc.txt
index 9ea3cb6..e86f16b 100644
--- a/advtrains/api_doc.txt
+++ b/advtrains/api_doc.txt
@@ -99,8 +99,9 @@ advtrains.register_wagon(name, prototype, description, inventory_image)
 	^- optional: Execute custom code on every step
 	custom_on_activate = function(self, dtime_s) end
 	^- optional: Execute custom code on activate. Staticdata does not need to be saved and restored since all properties written in 'self' are preserved over unloads.
-	update_animation = function(self, velocity) end
-	^- optional: Function that is called whenever the train's velocity changes or every 2 seconds. Used to call 'self.object:update_animation()' if needed. 
+	custom_on_velocity_change = function(self, velocity, old_velocity) end
+	^- optional: Function that is called whenever the train's velocity changes or every 2 seconds. Used to call 'self.object:update_animation()' if needed.
+	^- for compatibility reasons the name 'update_animation' for this function is still supported. 
 
 }
 
@@ -164,4 +165,4 @@ minetest.register_node(nodename, {
 		on_train_leave=function(pos, train_id) end
 		^- called when a train leaves the rail

 	}
-})
\ No newline at end of file
+})