Event System (Va.Si.Li-ES)

The event system lets users build event systems at run time, inside VR: triggers (an area is entered, an object is used, a timer runs out) start events (spawn, move or delete objects, teleport players, change the weather, start a vote or show feedback). Event systems can be saved as templates and loaded automatically when a scene starts. It is described in the paper Va.Si.Li-ES.

The code is in Assets/Lab/EventSystem (assembly Vasili.EventSystem). As a Unity package it is installed separately from the core, see Setting Up.

Concepts

Concept	Interface	Implementations (Runtime/...)
Event system	IEventSystem	EventSystem: holds triggers and events in numbered groups, can be repeatable
Trigger	ITrigger	Triggers/AreaTrigger, InteractionTrigger, TimeTrigger
Event	IEvent	Events/ObjectSpawningEvent, ObjectMovingEvent, ObjectDestructionEvent, PlayerTeleportationEvent, WeatherEvent, VotingEvent, FeedbackEvent, FollowingEventSystemEvent (starts another event system)
Modifier	IModifier	Modifiers/Modifier_Gravity, _Jump, _Speed, _Weather, _Zoom, _Map, _Admin; Modefier_Handler switches the modifiers in its Modifier_Container on or off according to the scene's ModifierSettings

When all triggers of a group have fired, the events of that group run. Group 0 is shared: its triggers are required by every group, and its events run whenever any group fires. A repeatable event system resets its triggers afterwards, otherwise it deletes itself. Triggers and events serialise themselves to JSON (createJson), which is how templates are stored.

Building blocks

Prefab	Purpose
Manager/EventSystemManager	Menu that lists the scene's event systems, loads templates and the scene's default event systems on start
Factory/EventSystemFactory	Creates one event system with its triggers and events
MarkerTool/MarkerTool	Tool for placing triggers and events in the scene
EnvironmentSystem/Weather/Weather_Controller	Weather (rain, snow, thunderstorm) used by WeatherEvent and Modifier_Weather
VotingSystem/Voting_Controller	Votes (yes/no or single choice) used by VotingEvent
FeedbackSystem/Notification Manager, FeedbackWindow	Notifications and feedback used by FeedbackEvent
EventSystemPrefabs/*	Ready-made items: binoculars, jump and sprint shoes, map, weather clouds, environment changer

To use it in a scene, add the EventSystemManager prefab (and the controllers for the events you need) to the scene.

Templates

EventSystemManager reads and writes templates at eventTemplates + "/defaultTemplates" (see Endpoints). A template belongs to the scene whose name it stores; templates of the current scene are offered in the template panel, and default ones are created when the scene loads.

Extending

• New trigger: a MonoBehaviour implementing ITrigger. Call notifySystem() when it fires, and return its state from getState().
• New event: a MonoBehaviour implementing IEvent. Do the work in trigger(), show what will happen in previewOn()/previewOff().
• New modifier: implement IModifier and add it to the Modifier_Container used by Modefier_Handler. The scene's ModifierSettings decide whether it is allowed and clamp its value.

Both triggers and events need createJson(groupID) so they can be saved in templates.