fix: trigger system getcomponentgroup in update (#17)

* mini refactor to cache trigger system component group when constructed instead of fetching on update

src/triggers/triggerSystem.ts

@@ -6,12 +6,15 @@ export class TriggerSystem implements ISystem {
 
  private _triggers: Record<string, TriggerWrapper> = {}
  private _cameraTriggerWrapper: CameraTrigger
+ private _componentGroup: ComponentGroup
 
  private constructor() {
  TriggerSystem._instance = this
  this._cameraTriggerWrapper = new CameraTrigger(
  new TriggerBoxShape(new Vector3(0.5, 1.8, 0.5), new Vector3(0, 0.91, 0))
  )
+
+ this._componentGroup = engine.getComponentGroup(TriggerComponent)
  }
 
  static createAndAddToEngine(): TriggerSystem {
@@ -31,9 +34,7 @@ export class TriggerSystem implements ISystem {
  }
 
  update() {
- //get entities with trigger component
- let entitiesWithTriggers = engine.getComponentGroup(TriggerComponent)
- .entities
+ let entitiesWithTriggers = this._componentGroup.entities
 
  //iterate through all entities with triggers and wrap entities that weren't wrapped yet
  entitiesWithTriggers.forEach(entity => {