Difference between revisions of "EventWML"

From The Battle for Wesnoth Wiki
(the [event] tag)
(The description of "[allow_undo]" was incorrect in claiming that you could conditionally employ it with "[if]"; I now link to my corrected explanation at DirectActionsWML.)
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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.  
 
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 ''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 ''secondary_unit'' below). '' {{DevFeature}} These units are stored in the variables 'unit' and 'second_unit' as if they had been stored using the '''[store_unit]''' tag. see [[SingleUnitWML]]<br><br>
 
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 ''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 ''secondary_unit'' below). '' {{DevFeature}} These units are stored in the variables 'unit' and 'second_unit' as if they had been stored using the '''[store_unit]''' tag. see [[SingleUnitWML]]<br><br>
 
 
  
 
* ''moveto'' triggers after ''primary_unit'' moves. Typically this is used when ''primary_unit'' gets to a particular location and a filter for the location of ''primary_unit'' is included; remember that this is the location that ''primary_unit'' lands on, not the location it started on or any location it travels on.
 
* ''moveto'' triggers after ''primary_unit'' moves. Typically this is used when ''primary_unit'' gets to a particular location and a filter for the location of ''primary_unit'' is included; remember that this is the location that ''primary_unit'' lands on, not the location it started on or any location it travels on.
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* ''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.''  
 
* ''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.''  
 
<br>
 
<br>
An '''[allow_undo]''' tag anywhere within a moveto event will cancel any lack of undo functionality the event would have
+
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. Note that '''[allow_undo]''' does not work within '''[if]''' tags, and that it causes out-of-sync errors in multiplayer games; check [[DirectActionsWML]] for the details.
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.
 
 
</li></ul>
 
</li></ul>
  

Revision as of 02:49, 5 June 2007

[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;

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 [scenario] (or [unit] - see event, UnitWML) 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 a side starts 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.
    • 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. 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 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 secondary_unit below). Template:DevFeature These units are stored in the variables 'unit' and 'second_unit' as if they had been stored using the [store_unit] tag. see SingleUnitWML

    • moveto triggers after primary_unit moves. Typically this is used when primary_unit gets to a particular location and a filter for the location of primary_unit is included; 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. Works only in shroud or fog.
    • attack this event triggers when primary_unit attacks secondary_unit.
    • attacker_hits this event triggers when the attacker (primary_unit) hits the defender (secondary_unit).
    • attacker_misses} same as attacker_hits, but is triggered when the attacker misses.
    • defender_hits this event triggers when the attacker (primary_unit) is hit in retaliation by the defender (secondary_unit).
    • 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 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.)
    • prerecruit Template:DevFeature this event triggers when primary_unit is recruited, but before it is displayed.
    • advance this event triggers just before primary_unit is going to advance to another unit.
    • post_advance this event triggers just after primary_unit has advanced to another unit.
    • select triggers when a 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.

    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. Note that [allow_undo] does not work within [if] tags, and that it causes out-of-sync errors in multiplayer games; check DirectActionsWML for the details.

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
  • [special_filter] and [special_filter_second] can be used to set some additional filtering criteria for primary_unit and 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.
    • weapon the name of the weapon used.
    • terrain the letter of the terrain the unit is on.

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 outer event executes. 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 simple and elegant way to accomplish more complex tasks without resorting to excessive if statements.

See Also