Advanced Trains [advtrains] API documentation
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To use the API, mods must depend on 'advtrains'.
All boolean values in definition tables default to 'false' and can be omitted.
### Wagons
Wagons are registered using the function

advtrains.register_wagon(name, prototype, description, inventory_image)
- 'name' is the internal name of the wagon. It should follow the mod naming convention, however, this is not enforced.
	For compatibility reasons, if a mod name is omitted, the wagon will be registered in the advtrains: namespace.
	Example: A wagon with name="engine_tgv" will be registered as "advtrains:engine_tgv".
	!IMPORTANT! You must not append a ":" at the start of the name, even if you want to bypass the mod naming convention check. This is because internally the register_wagon function
	appends a ":" automatically.
- 'prototype' is the lua entity prototype. The regular definition keys for luaentites apply. Additional required and optional properties see below. DO NOT define 'on_step', 'on_activate', 'on_punch', 'on_rightclick' and 'get_staticdata' since these will be overridden. Use 'custom_*' instead.
- 'description' is the description of the inventory item that is used to place the wagon.
- 'inventory_image' is the inventory image of said item.

# Wagon prototype properties
{
	... all regular luaentity properties (mesh, textures, collisionbox a.s.o)...
	drives_on = {default=true},
	^- used to define the tracktypes (see below) that wagon can drive on. The tracktype identifiers are given as keys, similar to privileges)
	max_speed = 10,
	^- optional, default 10: defines the maximum speed this wagon can drive. The maximum speed of a train is determined by the wagon with the lowest max_speed value.
	seats = {
	^- contains zero or more seat definitions. A seat is a place where a player can be attached when getting on a wagon.
		{
			name="Left front window",
			^- display name of this seat
			attach_offset={x=0, y=10, z=0},
			^- this value is passed to 'set_attach'
			view_offset={x=0, y=6, z=0},
			^- player:set_eye_offset is called with this parameter.
			group="default"
			^- optional. Defines the seat group. See 'seat_groups' below
			-!- Note: driving_ctrl_access field has moved to seat group definition,
			-!- but is still partwise supported here. If you don't use seat groups yet,
			-!- you really should change NOW!
		},
	},
	seat_groups = {
	^- If defined, activates advanced seating behavior. See "seating behavior".
		default = {
			name = "Seats"
			^- name of this seat group, to be shown in get-on menu.
			access_to = {"foo", "bar"}
			^- List of seat groups you can access from this seat using the menu when sitting inside the train.
			require_doors_open = true
			^- Only allow getting on and off if doors are open.
			driving_ctrl_access=false,
			^- If the seat is a driver stand, and players sitting here should get access to the train's driving control.
		}
	}
	assign_to_seat_group = {"default"},
	^- optional, like seat_groups. When player right_clicks the wagon, player will be assigned to the first free seat group in the list.
	
	doors={
	^- optional. If defined, defines door animation frames. Opposite door has to be closed during animation period.
	^- Remember, advtrains can't handle doors on both sides opened simultaneously.
		open={
			[-1]={frames={x=0, y=20}, time=1}, -- open left doors
			[1]={frames={x=40, y=60}, time=1}  -- open right doors
			sound = <simpleSoundSpec>
			^- The sound file of the doors opening. If none is specified, nothing is played.
		},
		close={
			[-1]={frames={x=20, y=40}, time=1}, -- close left doors
			[1]={frames={x=60, y=80}, time=1} -- close right doors
			sound = <simpleSoundSpec>
			^- The sound file of the doors closing. If none is specified, nothing is played.
		}
	},
	door_entry={ 1.5, -1.5 }
	^- optional. If defined, defines the locations of the doors on the model as distance from the object center on the path.
	^- Getting on by walking in then takes effect.
	^- Positive values mean front, negative ones back. Resulting position is automatically shifted to the right side.