EventWML

From The Battle for Wesnoth Wiki
Revision as of 06:37, 27 February 2009 by Voris (talk | contribs) (The [event] tag: indented all the bullet items that are values for 'name' and moved [allow_undo] blurb up to moveto tag it is relevant to)

[edit]WML Tags

A:

abilities, about, add_ai_behavior, advance, advanced_preference, advancefrom, advancement, advances, affect_adjacent, ai, allied_with, allow_end_turn, allow_extra_recruit, allow_recruit, allow_undo, and, animate, animate_unit, animation, aspect, attack, attack_anim, attacks, avoid;

B:

base_unit, berserk, binary_path, break, brush;

C:

campaign, cancel_action, candidate_action, capture_village, case, chance_to_hit, change_theme, chat, choose, clear_global_variable, clear_menu_item, clear_variable, color_adjust, color_range, command (action, replay), continue, criteria;

D:

damage, death, deaths, default, defend, defends, defense, delay, deprecated_message, destination, difficulty, disable, disallow_end_turn, disallow_extra_recruit, disallow_recruit, do, do_command, drains, draw_weapon_anim;

E:

editor_group, editor_music, editor_times, effect, else (action, animation), elseif, endlevel, end_turn (action, replay), enemy_of, engine, entry, era, event, extra_anim;

F:

facet, facing, fake_unit, false, feedback, female, filter (concept, event), filter_adjacent, filter_adjacent_location, filter_attack, filter_attacker, filter_base_value, filter_condition, filter_defender, filter_enemy, filter_location, filter_opponent, filter_own, filter_owner, filter_radius, filter_recall, filter_second, filter_second_attack, filter_self, filter_side, filter_vision, filter_weapon, filter_wml, find_path, fire_event, firststrike, floating_text, for, foreach, frame, full_heal;

G:

game_config, get_global_variable, goal, gold, gold_carryover;

H:

harm_unit, has_ally, has_attack, has_unit, have_location, have_unit, heal_on_hit, heal_unit, healed_anim, healing_anim, heals, hide_help, hide_unit, hides;

I:

idle_anim, if (action, animation), illuminates, image, init_side, insert_tag, inspect, item, item_group;

J:

jamming_costs, join;

K:

kill, killed;

L:

label, language, leader, leader_goal, leadership, leading_anim, levelin_anim, levelout_anim, lift_fog, limit, literal, load_resource, locale, lock_view, lua;

M:

male, menu_item, message, micro_ai, missile_frame, modification, modifications, modify_ai, modify_side, modify_turns, modify_unit, modify_unit_type, move, move_unit, move_unit_fake, move_units_fake, movement_anim, movement costs, movetype, multiplayer, multiplayer_side, music;

N:

not, note;

O:

object, objective, objectives, on_undo, open_help, option, options, or;

P:

part, petrifies, petrify, place_shroud, plague, poison, portrait, post_movement_anim, pre_movement_anim, primary_attack, primary_unit, print, put_to_recall_list;

R:

race, random_placement, recall (action, replay), recalls, recruit, recruit_anim, recruiting_anim, recruits, redraw, regenerate, remove_event, remove_item, remove_object, remove_shroud, remove_sound_source, remove_time_area, remove_unit_overlay, repeat, replace_map, replace_schedule, replay, replay_start, reset_fog, resistance (ability, unit), resistance_defaults, resource, return, role, rule;

S:

save, scenario, scroll, scroll_to, scroll_to_unit, secondary_attack, secondary_unit, section, select_unit, sequence, set_extra_recruit, set_global_variable, set_menu_item, set_recruit, set_specials, set_variable, set_variables, sheath_weapon_anim, show_if (message, set_menu_item), show_objectives, side, skirmisher, slow, snapshot, sound, sound_source, source (replay, teleport), special_note, specials, split, stage, standing_anim, statistics, status, store_gold, store_items, store_locations, store_map_dimensions, store_reachable_locations, store_relative_direction, store_side, store_starting_location, store_time_of_day, store_turns, store_unit, store_unit_defense, store_unit_type, store_unit_type_ids, store_villages, story, swarm, switch, sync_variable;

T:

target, team, teleport (ability, action), teleport_anim, terrain, terrain_defaults, terrain_graphics, terrain_mask, terrain_type, test, test_condition, text_input, textdomain, theme, then, tile, time, time_area, topic, toplevel, trait, transform_unit, traveler, true, tunnel, tutorial;

U:

unhide_unit, unit, unit_overlay, unit_type, unit_worth, units, unlock_view, unpetrify, unstore_unit, unsynced;

V:

value, variable, variables, variant, variation, victory_anim, village, vision_costs, volume;

W:

while, wml_message, wml_schema;

Z:

zoom;

The [event] tag

This tag is a subtag of the [scenario], [unit] and [era] tags which is used to describe a set of actions which trigger at a certain point in a scenario. When used in a [scenario] tag (also includes [multiplayer], [tutorial] and [test]), the event only occurs in that scenario. When used in a [unit] type definition, the event will occur in all scenarios in which a unit of that type appears in. When used in an [era], the event will occur in any scenario which is played using that era.

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. Template:DevFeature name can accept a list of commas separated descriptions for which the event must be triggered. Example: name= attacker_misses, defender_misses. Note that unless you use first_time_only=no, the event will fire only once, not once for each listed type.
    • 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 a side is about to start its turn. Before 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. This is before any healing takes place for that side, before calculating income, and before restoring unit movement and status.
    • turn refresh: this event triggers just before a side is taking control after healing, calculating income, and restoring unit movement and status.
    • turn X: (for X some number) 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=yes (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. It helps debugging if the victory event allows you to safely advance to any of the possible next maps after using the ":n" command. Scenarios where key units are picked up before the victory, or where some action chosen earlier determines which map to advance to, make it hard to quickly test scenarios in a campaign. (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)
    • ai turn: is triggered just before the AI is invoked for a side. This is called after side turn, and thus the WML variable side_number still holds the number of this side.
Filters can be applied to the following event triggers (see FilterWML; see also below). The actions specified in the event tag will be executed only if the filter returns true.
These event triggers are all actions by units (moveto, attack) or things that happen to units (recruit, advance). When one of these events is triggered, the position of the active unit (referred to as the primary unit) is stored in the variables x1 and y1 and the position of any unit that primary unit does something to is stored in the variables x2 and y2 (this unit is referred to as the secondary unit below). These units are also automatically stored in the variables 'unit' and 'second_unit' as if they had been stored using the [store_unit] tag. see SingleUnitWML
  • moveto: triggers after the primary unit moves. Typically this is used when the primary unit gets to a particular location and a filter for the location of the primary unit is included; remember that this is the location that the primary unit lands on, not the location it started on or any location it travels on.
An [allow_undo] tag anywhere within a moveto event will cancel any lack of undo functionality the event would have caused. Note that undo functionality will only move the unit back to its former location; it will not other changes to the game caused by the event. Thus it is up to the scenario designer to use this tag correctly.
  • sighted: this event triggers when the primary unit becomes visible to the secondary unit in particular after not being visible to the secondary unit's side (so if the secondary unit's side doesn't have shroud or fog, the event never triggers). This happens both when the primary unit moves into view during its turn, and when the secondary unit moves to a location where it can see the primary unit. (This editor hasn't tested whether the event triggers multiple times if the primary unit moves into view of multiple units at once, or if not, which one gets chosen to be the secondary unit here.) (Note: it appears that when a sighted event is triggered because an enemy unit moves into your field of view, the game engine cannot determine which unit (on your side) sees the unit that moved, and so it fires a name=sighted event without setting $second_unit. This means that, for example, using speaker=second_unit inside a message tag may fail.)
  • attack: this event triggers when the primary unit attacks the secondary unit.
  • attacker_hits: this event triggers when the the primary unit (the attacker) hits the secondary unit (the defender). Template:DevFeature A variable $damage_inflicted allow to check the number of hitpoints inflicted by the attacker.
  • attacker_misses: same as attacker_hits, but is triggered when the attacker misses.
  • defender_hits: this event triggers when the primary unit (the attacker) is hit in retaliation by the secondary unit (the defender). Template:DevFeature A variable $damage_inflicted allow to check the number of hitpoints inflicted by the defender.
  • defender_misses: same as defender_hits, but is triggered when the defender misses.
  • attack_end: is similar to attack, but is instead triggered after the fight, not before. Note that if either unit is killed during the fight, this event triggers before any die events.
  • stone: this event triggers when the primary unit is hit by an attack with the 'stones' ability (See stones, AbilitiesWML) by the secondary unit (the unit with the 'stones' ability).
  • last breath: this event triggers when the primary unit is killed by the secondary unit, but before the death animation is triggered.
  • die: this event triggers when the primary unit is killed by the secondary unit.
  • capture: this event triggers when the 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 the 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.). Template:DevFeature The recruit will no longer triggers on recalls.
  • prerecruit: this event triggers when the primary unit is recruited, but before it is displayed. Template:DevFeature The prerecruit will no longer triggers on recalls.
  • advance: this event triggers just before the primary unit is going to advance to another unit.
  • post_advance: this event triggers just after the primary unit has advanced to another unit.
  • select: triggers when the primary unit is selected. Note: in networked multiplayer, these events are only executed by the client on which the event is triggered, leading to out of sync errors if you modify the game state in the event.
  • menu item X: triggers when a WML menu item with id=X is selected. Note: if the menu item has a [command], this event may be executed before or after the command; there is no guarantee.
  • Template:DevFeature prerecall: triggers when a unit is recalled, but before it is displayed. This event is not trigger when a unit is recruit.
  • Template:DevFeature recall: triggers after a unit is recalled. This event is not trigger when a unit is recruit.
  • Template:DevFeature other events with a custom name may be invoked from [fire_event]
  • Template:DevFeature consider attack: triggers before the attack dialog is displayed.
  • Template:DevFeature unconsider attack: triggers when canceling out of the attack dialog.

The primary unit can be referred to as unit and the secondary unit can be referred to as second_unit in [message] tags using the speaker= key. 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 the primary unit matches this filter.
  • [filter_second]: is like [filter], but for the secondary unit.
  • [special_filter] and [special_filter_second]: can be used to set some additional filtering criteria for the primary unit and the secondary unit that are not generally available in a standard unit filter. Can be used in events attack, attacker_hits, attacker_misses, defender_hits, defender_misses and attack_end. (Template:DevFeature renamed to [filter_attack] and [filter_second_attack])

Actions triggered by [event]

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:

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".

Nested events

There is 1 special type of action: event creation. By placing an [event] tag inside another [event] tag, the nested event is created when the nested event is encountered (when executing the contents of the event). For example, you could create a portal that opens on turn 10. The outer event executes on turn 10, creating the nested moveto event, which executes when a player steps on a certain spot. An equivalent way of doing this would be to a single moveto event with an [if] statement to check for turn number, but using nested [event] tags is a convenient shortcut to accomplish this task without resorting to [if] statements.

Example:

[event]
    name=turn 10

    [event]
        name=moveto

        [filter]
            x,y=5,8
        [/filter]

        # moving to 5,8 will trigger this event only on turn 10 and after
    [/event]
[/event]

Variable substitution for a nested event can happen either when the event is spawned, or when it is triggered. This is controlled with the key delayed_variable_substitution (default yes). Consider the following two examples:

# This makes the message display the turn on which the moveto happens,
# because the variable substitution for the moveto event will be done
# when the event triggers.

[event]
    name=turn 2

    [event]
        name=moveto
        delayed_variable_substitution=yes

        {DEBUG_MSG "Turn $turn_number"}
    [/event]
[/event]
# This makes the message on moveto always display as "Turn 2", because
# the variable substitution is done when the moveto event is spawned,
# not when it eventually triggers.

[event]
    name=turn 2

    [event]
        name=moveto
        delayed_variable_substitution=no

        {DEBUG_MSG "Turn $turn_number"}
    [/event]
[/event]

Another way to mark an individual variable to be substituted later (when the event is triggered) is to write it as "$|var" instead of the normal "$var". By combining this with delayed_variable_substitution=no you can have some variables in the nested event be substituted immediately when the event is spawned and some variables substituted when the event triggers.

See Also