Triggers
RuneScript operates primarily via **triggers**, which describe how and when to execute functions. Triggers consist of two parts: the trigger itself, and a subject.
Triggers will fire when a player interacts with the game world (typically by clicking) and the functions executed by the trigger are responsible for what actions the game engine will take after the player clicks.
Nearly everything a player does in-game will fire some sort of trigger. Likewise almost all RuneScript is written to execute in response to a fired trigger.
Triggers can be placed in any RuneScript file and the order of triggers does not matter, however it still pays to stay organized!
Types of Triggers
There are several dozen different triggers but they can be divided up into three main types:
* **Specific** triggers fire when the player interacts with a single subject, and use the syntax `[trigger,subject]`
* **Category** triggers fire when the player interacts with any subjects in a particular category. Categories are prefixed with an underscore so the syntax looks like `[trigger,_category]`
* The **global** trigger acts as a fallback and fires if no other triggers exist for that subject ("*Nothing interesting happens*"). The global trigger actually uses a category so the syntax is `[trigger,_]`
Triggers: `op` versus `ap`
Most triggers you will encounter in everyday use are prefixed with either `op` or `ap`:
* `op`: **Operable** within one tile, requires line of walk, restricted to cardinal directions
* `ap`: **Approachable** within 10 tiles, requires line of sight
In a nutshell `op` triggers are used for interactions within melee distance (one tile away) and `ap` triggers are used for interactions at range (between two and ten tiles away).
Trigger Naming Convention
Breaking down a bit further, triggers can be categorized by subject type. Different triggers are intended to fire upon interaction with different types of subjects:
* Player subjects: `opplayer1-5`/`applayer1-5`
* NPC subjects: `opnpc1-5`/`apnpc1-5`
* Loc subjects: `oploc1-5`/`aploc1-5`
* "Loc" (or *location*) is the Jagex term which refers to any interactable (clickable) scenery found in the game.
* Objects on the ground: `opobj`/`apobj`
* "Object" refers to items, either on the ground or held in the inventory
* Objects held in the inventory: `opheld1-5`/`opheldu` (held objects cannot be `ap`proached)
There are more triggers but this gives you an idea of how the naming convention works.
Examples of Common Triggers
Here are some real-world examples of common triggers you will encounter:
* `[opnpc1,border_guard_lumby]`
* This is the trigger that fires when a player clicks on a Lumbridge border guard within melee distance. It is a **specific** trigger because its subject is not prefixed by an underscore.
* The trigger being used here is `opnpc1` which is shorthand for performing `op`eration `1` on an `npc`.
* Operation 1 for the border guard is `Talk-to`.
* `[oploc1,_door_closed]`
* This trigger fires when the player clicks any door in the `door_closed` category within melee distance. This is a **category** trigger because its subject is prefixed with `_`.
* This is a **loc** trigger because a door is clickable/interactable scenery and is therefore referred to as a loc.
* The trigger used is `oploc1`, and operation 1 on closed doors of this category is `Open`.
* `[applayeru,rotten_tomato]`
* This trigger fires when the player uses a rotten tomato on another player from `ap`roachable distance (at a range of between 2 and 10 tiles).
* This is a **specific** trigger because it will only fire when the used item is a rotten tomato.
* It is also a `player` trigger so it will not fire if e.g. a player uses the rotten tomato on an NPC (that would be `apnpcu`).
Now you understand how to set triggers in RuneScript. The syntax is fairly simple: your desired trigger and its subject, separated by a comma, and enclosed in brackets.