import Scene from './scene' ; import ModelInstance from './modelinstance' ; import EmittedObject from './emittedobject' ; /**
 * An emitter.
 */ export default abstract class Emitter { instance : ModelInstance ; objects : EmittedObject [ ] = [ ] ; alive = 0 ; currentEmission = 0 ; abstract createObject ( ) ; abstract updateEmission ( dt ) ; abstract emit ( ) ; constructor ( instance ) { this . instance = instance ; } /**
     * Update this emitter.
     */ update ( dt ) { this . updateEmission ( dt ) ; const currentEmission = this . currentEmission ; if ( currentEmission >= 1 ) { for ( let i = 0 ; i < currentEmission ; i += 1 ) { this . emit ( ) ; } } } /**
     * Clear any emitted objects.
     */ clear ( ) { const objects = this . objects ; for ( let i = 0 , l = this . alive ; i < l ; i ++ ) { const object = objects [ i ] ; object . health = 0 ; } this . currentEmission = 0 ; } emitObject ( emitData ? ) { const objects = this . objects ; if ( this . alive === objects . length ) { objects . push ( this . createObject ( ) ) ; } const object = objects [ this . alive ] ; object . index = this . alive ; object . bind ( emitData ) ; this . alive += 1 ; this . currentEmission -= 1 ; const scene = < Scene > this . instance . scene ; scene . emittedObjectUpdater . add ( object ) ; return object ; } kill ( object ) { const objects = this . objects ; this . alive -= 1 ; const otherObject = objects [ this . alive ] ; objects [ object . index ] = otherObject ; objects [ this . alive ] = object ; otherObject . index = object . index ; object . index = - 1 ; } }