Solarus quests  1.5
Quest maker's reference
Equipment items

An equipment item represents something that the player can obtain (one or more times, in various forms and with several variants) and possibly keep. The Lua item type described in this page provides various functions to

  • get and the possession state of a equipment item,
  • set its properties, like whether the item is saved and has an amount,
  • control its dynamic behavior, like what happens when the player uses this item (for items that can be used).

A Lua item object represents a kind of treasure, and not a particular instance of treasures. Individual treasures may then be represented as pickable treasures, chests, shop treasures, and may be brandished by the hero. For example, multiple treasures of the kind "rupee" may exist at the same time during the game, but only one Lua item object manages them.

The script file items/XXXX.lua defines the item named XXXX. The corresponding Lua item object is passed as parameter of that script. Use the Lua notation "..." to get this parameter and store it into a regular variable.

Here is a basic example of script for the rupee item, an item whose only role is to increase the money of the player when he obtains a rupee.

-- First, we put the parameter into a variable called "rupee".
-- (In Lua, the notation "..." refers to the parameter(s) of the script.)
local rupee = ...

-- Event called when the hero obtains a rupee treasure.
function rupee:on_obtaining()
  self:get_game():add_money(1)  -- Increase the money of 1 unit.
end
Remarks
All item scripts are loaded when you create a savegame object. Indeed, equipment items only exist in the context of a particular savegame. As shown in the example above, you can retrieve that savegame with item:get_game().
A sprite animation named XXXX must also exist in the sprite entities/items: it is used by the engine whenever it needs to draw your item on the map (for example, when a pickable treasure of this kind is created on the map).

Methods of the type item

item:get_name()

Returns the name of this item.

  • Return value (string): The name that identifies this item. It is also the file name of the item script (without the extension).

item:get_game()

Returns the game where this item belongs.

  • Return value (game): The game that contains this item.
Remarks
Items only exist in the context of a game, but the game is not necessarily running.

item:get_map()

Returns the current map.

  • Return value (map): The current map, or nil if the game is not running.

item:get_savegame_variable()

Returns the name of the integer savegame value that stores the possession state of this item.

  • Return value (string): The savegame variable that stores the possessed variant of this item, or nil if this item is not saved.

item:set_savegame_variable(savegame_variable)

Sets the name of the integer savegame value that stores the possession state of this item.

You should call this function at initialization time if you want your item to be saved.

  • savegame_variable (string): The savegame variable that should stored the possessed variant of this item, or nil to make this item unsaved.

item:get_amount_savegame_variable()

Returns the name of the integer savegame value that stores the amount associated to this item.

  • Return value (string): The savegame variable that stores the possessed amount of this item, or nil if this item has no associated amount.

item:set_amount_savegame_variable(amount_savegame_variable)

Sets the name of the integer savegame value that stores the amount of this item.

You should call this function at initialization time if you want your item to store an amount (in addition to its possessed variant). This is typically used for items like the bow and the counter of bombs.

  • Return value (string): The savegame variable that should store the possessed amount of this item, or nil to make this item have no associated amount.

item:is_obtainable()

Returns whether the player is allowed to obtain this item.

If not, any treasure representing this item is automatically replaced by an empty treasure.

  • Return value (boolean): true if this item is obtainable.

item:set_obtainable([obtainable])

Sets whether the player is allowed to obtain this item.

If not, any treasure representing this item is automatically replaced by an empty treasure. There is no risk that the player can obtain it or even see it during the game. You can use this feature to hide some items while the player has not the necessary equipment. For example, you can make arrows unobtainable until the player has the bow. You can also make magic jars unobtainable until the player has a magic bar.

  • Return value (boolean, optional): true if this item is obtainable (no value means true).

item:is_assignable()

Returns whether this item can be assigned to an item slot.

When the item is assigned to a slot, the player can use it by pressing the game command of that slot. Some items are meant to be used by pressing a command (like the bow), other are not supposed to (like a key or a rupee). When the player uses your item, the event item:on_using() is triggered.

  • Return value (boolean): true if this item is assignable.

item:set_assignable([assignable])

Sets whether this item should be assignable to an item slot.

When the item is assigned to a slot, the player can use it by pressing the game command of this slot. Some items are meant to be used by pressing a command (like the bow), other are not supposed to (like a key or a rupee). When the player uses your item, the event item:on_using() is triggered.

By default, an item is not assignable. Call this function at initialization time if you want your item to be assignable.

  • assignable (boolean, optional): true if this item is assignable (no value means true).

item:get_can_disappear()

Returns whether pickable treasures of this kind disappears after a few seconds when they are dropped by an enemy or a destructible entity.

  • Return value (boolean): true if pickable treasures of this kind can disappear.

item:set_can_disappear([can_disappear])

Sets whether pickable treasures of this kind should disappear after a few seconds when they are dropped by an enemy or a destructible entity.

By default, an item cannot disappear. Call this function at initialization time if you want your item to be ephemeral.

  • can_disappear (boolean, optional): true to make such pickable treasures disappear after a few seconds (no value means true).
Remarks
This property only applies to pickable treasures dropped dynamically (by enemies and destructible entities). Pickable treasures already present on the map when the map starts don't disappear with time.

item:get_brandish_when_picked()

Returns whether the hero brandishes treasures of this kind when he picks them on the ground.

  • Return value (boolean): true if the hero brandish such treasures.

item:set_brandish_when_picked([brandish_when_picked])

Sets whether the hero should brandish treasures of this kind when he picks them on the ground.

Treasures coming from a chest are always brandished, even the most basic ones like simple rupees. However, when treasures are picked on the ground (like rupees dropped by an enemy), you may want the hero not to brandish them.

By default, this property is true. Call this function if you don't want your item to be brandished when it is picked on the ground.

  • brandish_when_picked (boolean, optional): true if the hero should brandish such treasures (no value means true).

item:get_shadow()

Returns the name of the animation representing the shadow of this item in the sprite "entities/shadow".

  • Return value (string): Name of the shadow animation adapted to this item in the sprite "entities/shadow". nil means no shadow displayed.

item:set_shadow(shadow_animation)

Sets the name of the animation that should represent the shadow of this item in the sprite "entities/shadow".

When the engine needs to show a treasure representing your item, it sometimes also wants to display a shadow (in addition of the treasure's main sprite). For example, pickable treasures dropped by enemies normally have a shadow.

The default shadow animation is "big". You should call this function at initialization time if your item sprite is larger or smaller than usual.

  • shadow_animation (string): Name of the shadow animation in the sprite "entities/shadow" to set for this item. nil means that no shadow will be displayed.
Remarks
To draw a treasure, the engine relies on two sprites: the treasure's main sprite (entities/item) and the shadow's sprite (entities/shadow). Both sprites and their appropriate animations must exist so that treasures can be displayed correctly.

item:get_sound_when_picked()

Returns the sound played when the hero picks a treasure of this kind.

  • Return value (string): Name of the sound played when the hero picks a treasure of this kind (nil means no sound).

item:set_sound_when_picked(sound_when_picked)

Sets the sound to play when the hero picks a treasure of this kind.

The default sound is "picked_item".

  • sound_when_picked (string): Name of the sound to play (as in sol.audio.play_sound()) when the hero picks a treasure of this kind (nil means no sound).
Remarks
This sound is always played, even if the treasure is also brandished then (i.e. if item:get_brandish_when_picked() returns true).

item:get_sound_when_brandished()

Returns the sound played when the hero brandishes a treasure of this kind.

  • Return value (string): Name of the sound played when the hero brandishes a treasure of this kind (nil means no sound).

item:set_sound_when_brandished(sound_when_brandished)

Sets the sound to play when the hero brandishes a treasure of this kind.

The hero can brandish treasures in various situations: when opening a chest, when buying a shop treasure, when picking up a pickable treasure (unless you called item:set_brandish_when_picked(false)), and also when you call hero:start_treasure() directly.

The default sound is "treasure".

  • sound_when_brandished (string): Name of the sound to play (as in sol.audio.play_sound()) when the hero brandishes a treasure of this kind (nil means no sound).

item:has_variant([variant])

Returns whether the player owns at least the specified variant of this item (only for a saved item).

  • variant (number, optional): The variant to check (default 1).
  • Return value (boolean): true if the player has at least this variant.
Remarks
Equivalent to item:get_variant() >= variant.

item:get_variant()

Returns the possession state of this item (only for a saved item).

  • Return value (number): The possession state (0: not possessed, 1: first variant, 2: second variant, etc.).
Remarks
Equivalent to item:get_game():get_value(item:get_savegame_variable()).

item:set_variant(variant)

Sets the possession state of this item (only for a saved item).

  • variant (number): The new possession state to set (0: not possessed, 1: first variant, 2: second variant, etc.)
Remarks
Equivalent to item:get_game():set_value(item:get_savegame_variable(), variant).

item:has_amount([amount])

Returns whether this item has an associated amount, or whether the player has at least the specified value.

  • amount (number, optional): The amount to check. If this parameter is not set, this function only tests whether an amount value exists for the item.
  • Return value (boolean): If an amount is specified, return true if the player has at least that amount. Otherwise, returns true if the item has an amount value.
Remarks
If an amount is specified, this method is equivalent to item:get_amount() >= amount. Otherwise, this method is equivalent to item:get_amount_savegame_variable() ~= nil.

item:get_amount()

Returns the amount associated to this item (only for an item with an amount value).

  • Return value (number): The associated amount.
Remarks
Equivalent to item:get_game():get_value(item:get_amount_savegame_variable()).

item:set_amount(amount)

Sets the amount associated to this item (only for an item with an amount value). A negative amount will be replaced by 0. An amount greater than item:get_max_amount() will be replaced by that maximum value.

  • amount (number): The amount to set.

item:add_amount(amount)

Increases the amount associated to this item (only for an item with an amount value), without exceeding the maximum amount.

  • amount (number): The amount to add.

item:remove_amount(amount)

Decreases the amount associated to this item (only for an item with an amount value), without going below 0.

  • amount (number): The amount to remove.

item:get_max_amount()

Returns the maximum amount associated to this item (only for an item with an amount value).

  • Return value (number): The maximum amount.

item:set_max_amount(max_amount)

Sets the maximum amount associated to this item (only for an item with an amount value). This maximum value is used in item:set_amount() and item:add_amount() to make a limit. The default value is 1000.

  • max_amount (number): The maximum amount to set.
Remarks
The maximum amount of an item is not saved automatically. Only the current variant (see item:set_savegame_variable()) and the current amount (see item:set_amount_savegame_variable()) are saved by the engine. Therefore, you have to set the maximum amount of appropriate items when they are loaded (typically from event item:on_started()).

item:set_finished()

Notifies the engine that using this item is finished and that the hero can get back to a normal state.

When the player uses this item (by pressing an item game command), your item script takes full control of the hero (event item:on_using() is called) and you have to program the item's behavior. When it is finished, call this function to restore normal control to the player.

This method should only be called when the hero is using this item.

Events of an item

Events are callback methods automatically called by the engine if you define them. In the case of a game, they are only called on the game currently running, if any.

item:on_created()

Called when your item script is being created, that is, when the game object is being created.

In this event, you should initialize your item.

Remarks
All items scripts are not loaded yet at this time. Your item is being loaded, but you don't know the status of the other ones. Unless your item is the last one to be initialized, other items are not ready. If your item needs to get some properties from other items in its initialization, use item:on_started() instead.

item:on_started()

Called when your item starts, that is, once all items are created.

At this time, all items scripts are loaded and their on_created() events have been called.

You can use this event to make initializations that depend on other items. Such initializations could not be done earlier from item:on_created(), because all items did not exist at that time.

item:on_finished()

Called when the game stops running.

item:on_update()

Called at each cycle of the main loop while the game is running.

Remarks
As this function is called at each cycle, it is recommended to use other solutions when possible, like timers and other events.

item:on_suspended(suspended)

Called when the map is being suspended or resumed. Only possible when the game is running.

The map is suspended by the engine in a few cases, like when the game is paused or when the camera is being moved by a script. When this happens, all map entities stop moving and most sprites stop their animation. Your item may need to be notified.

  • suspended (boolean): true if the map is being suspended, false if it is being resumed.

item:on_map_changed(map)

Called when the player has just entered a map. Only possible when the game is running.

The new map is already started at this point.

  • map (map): The new active map.
Remarks
This event is also called for the first map (when your game starts).

item:on_pickable_created(pickable)

Called when a pickable treasure of your item's kind is created on the map. Only possible when the game is running.

If you need to do something special when a pickable treasure of this kind appears on the map, like setting a particular movement, you can use this event.

item:on_obtaining(variant, savegame_variable)

Called when the hero is obtaining a treasure of this kind of item. Only possible when the game is running.

  • variant (number): The variant of item (because some items may have several variants). 1 is the first variant, 2 is the second variant, etc.
  • savegame_variable (string): Name of the boolean saved value that stores the state of the treasure being obtained. nil means that the treasure is not saved.
Remarks
If the treasure is brandished, this function is called immediately (before the dialog starts). If you want to do something after the treasure's dialog, see item:on_obtained().

item:on_obtained(variant, savegame_variable).

Like item:on_obtaining(), but called right after the treasure is obtained. Only possible when the game is running.

In the case of a brandished treasure, this event is called once the treasure's dialog is finished. Otherwise, it is called immediately after item:on_obtaining().

  • variant (number): The variant of item (because some items may have several variants). 1 is the first variant, 2 is the second variant, etc.
  • savegame_variable (string): Name of the boolean saved value that stores the state of the treasure just obtained. nil means that the treasure is not saved.

item:on_variant_changed(variant)

Called when the possessed variant of this item has just changed. Only for saved items.

This event is triggered whenever the variant changes: it can be when the hero obtains a treasure of this item's kind, or when you call item:set_variant() explicitly.

  • variant (number): The new variant possessed (possibly 0).

item:on_amount_changed(amount)

Called when the possessed amount of this item has just changed. Only for items with an associated amount.

This event is triggered when you call item:set_amount(), item:add_amount(), item:remove_amount(),

  • amount (number): The new amount possessed (possibly 0).

item:on_using()

Called when the player is using this item. Only possible when the game is running, and only for assignable items.

The player is using your item (by pressing an item game command). You now have full control of the hero. From this event, you have to program the item's behavior. For example, your item can remove some magic points and perform an special attack that kills all enemies nearby. When you have finished, call item:set_finished() to restore normal control to the player.

Remarks
There is another event for the special case of giving an item to an non-playing character. If the hero uses an item in front of an NPC whose property is to notify your item, then event item:on_npc_interaction_item() is triggered first. If that event is defined and returns true, then item:on_using() is not called (the interaction is considered done).

item:on_ability_used(ability_name)

Called when the player has just performed a built-in ability. Only possible when the game is running.

Built-in abilities indicate whether the hero can perform some built-in actions like attacking, swimming or running. See game:get_ability() for more details.

  • ability_name (string): Name of the ability that was used.

item:on_npc_interaction(npc)

Called when the hero interacts (the player pressed the action command) in front of an NPC whose property is to notify your item. Only possible when the game is running.

  • npc (NPC): A non-playing character.

item:on_npc_interaction_item(npc, item_used)

Called when the hero uses any item (the player pressed an item command) with an NPC whose property is to notify your item. Only possible when the game is running.

  • npc (NPC): A non-playing character.
  • item_used (item): The item currently used by the player. This is not necessarily your item. The reason why your item gets notified is because the NPC is related to your item. But the player may be using another item.
  • Return value (boolean): true if an interaction happened. If you return false or nothing, then item_used:on_using() will be called (just like if there was no NPC in front of the hero).

item:on_npc_collision_fire(npc)

Called when an NPC whose property is to notify your item touches fire. Only possible when the game is running.

  • npc (npc): A non-playing character that touches fire and has the property to notify your item.