EventWML

From The Battle for Wesnoth Wiki
Revision as of 16:55, 25 August 2005 by Allefant (talk | contribs) (more formatting)

the [event] tag

This tag is a subtag of [scenario] which is used to describe a set of actions which trigger at a certain point in the scenario.

keys and tags that describe when the event should trigger:

  • name this is not like a normal 'name' key. It is a basic description of when the event will trigger.
    • 'prestart' the event is triggered before a scenario 'starts' -- before anything is shown on the screen at all. You can use this event to set up things like village ownership. For things displayed on-screen such as character dialog, use 'start'.
    • 'start' this event triggers after the map is shown but before the scenario begins
    • 'new turn' this event triggers whenever the last player ends their turn. See also first_time_only=no. When the last player ends their turn, before any events of this type trigger, the value of the WML variable turn_number is set to the number of the turn that is beginning.
    • 'side turn' this event triggers when any player ends their turn. When a player ends their turn, before any events of this type trigger, the value of the WML variable side_number is set to the number of the side of the player about to take their turn.
    • 'turn X' this event triggers at the start of turn X. X cannot be 1.
    • 'time over' this event triggers on turn turns. (turns is specified in [scenario])
    • 'enemies defeated' this event triggers when all units with canrecruit=1 (i.e. all leaders) not allied with side 1 are killed.
    • 'victory' in this scenario, any tag of the form [endlevel] result=victory [/endlevel] will be automatically preceded by all actions in this tag. (See also [endlevel], DirectActionsWML)
    • 'defeat' in this scenario, any tag of the form [endlevel] result=defeat [/endlevel] will be automatically preceded by all actions in this tag. (See also [endlevel], DirectActionsWML)
    Events with the following trigger types can be filtered on (see FilterWML) Whenever one of these events is triggered, the position of primary_unit is stored in the variables 'x1' and 'y1', and the position of secondary_unit is stored in 'x2' and 'y2'.
    • 'moveto' triggers after primary_unit moves. Usually the location of primary_unit is also filtered on; remember that this is the location that primary_unit lands on, not the location it started on or any location it travels on.
    • 'sighted' this event triggers when primary_unit moves to a location where secondary_unit is in primary_unit's sight range
    • 'attack' this event triggers when primary_unit attacks secondary_unit
    • 'stone' this event triggers when primary_unit is hit by an attack with the 'stones' ability (See stones//, AbilitiesWML) by secondary_unit (secondary_unit is the unit with the 'stones' ability.)
    • 'die' this event triggers when primary_unit is killed by secondary_unit
    • 'capture' this event triggers when primary_unit captures a village. The village may have been previously neutral, or previously owned by another side; merely moving into your own villages does not constitute a capture.
    • 'recruit' this event triggers when primary_unit is recruited or recalled. (That is, when a unit is recruited or recalled, it will trigger this event and this event's filter will filter that unit.)
    An [allow_undo] tag anywhere within a moveto event will cancel any lack of undo functionality the event would have caused. It is up to the scenario designer to avoid abusing this command by allowing undo on events that shouldn't be undoable. The results of doing this may be strange. This actually does have functionality beyond aesthetics like signs: suppose you have an event that performs some action depending on the condition of an 'if' statement. This event might be executed on every single move, but the body of the 'if' statement entered only in a few cases. Previously this would completely disable undo for the entire scenario, while now it can be made to only disable undo in the cases where the event mutates the scenario.

Primary_unit can be referred to as unit and Secondary_unit can be referred to as second_unit in [message] tags. For example:

[event]
name=die
  [message]
  speaker=second_unit
  message="Hahaha, I finally killed you!"
  [/message]

  [message]
  speaker=unit
  message="It's not over yet! I'll come back to haunt you!"
  [/message]
[/event]

These keys and tags are more complex ways to filter when an event should trigger:

  • first_time_only whether the event should be removed from the scenario after it is triggered. Default is 'yes'.
  • [filter] the event will only trigger if primary_unit matches this filter.
    • standard unit filter - attributes for [filter] are described in FilterWML
  • [filter_second] is like [filter], but for secondary_unit
    • standard unit filter

After the trigger conditions have been met, all action tags within the [event] tag are executed in the order they are written in.

There are 3 main types of actions: internal actions (InternalActionsWML) which are used by WML internally, display actions (InterfaceActionsWML) which show something to the user, and direct actions (DirectActionsWML) which have a direct effect on gameplay.

Several actions use standard filters to find out which units to execute the command on. These are denoted by the phrases "standard unit filter" and "standard location filter".

See Also