RoApp/Assets/Flux/Runtime/Events/Particle/FPlayParticleEvent.cs

using UnityEngine;
using System.Collections;

namespace Flux
{
	//[FEvent( "Particle System/Play Particle", typeof(FParticleTrack) )]
	public class FPlayParticleEvent : FEvent {

		[SerializeField]
		[Tooltip("True: ParticleSystem playback speed will be adjusted to match event length"
		         +"\nFalse: ParticleSystem plays at normal speed, i.e. doesn't scale based on event length")]
		private bool _normalizeToEventLength = false;

		[SerializeField]
		[HideInInspector]
		[Tooltip("Seed to randomize the particle system, 0 = always randomize")]
		private uint _randomSeed = 1;

		private ParticleSystem _particleSystem = null;

		private float _previousTimeSinceTrigger = 0;

		private float _previousSpeed = 0;

		protected override void OnInit ()
		{
			_particleSystem = ((FParticleTrack)Track).ParticleSystem;

			if( _particleSystem != null )
			{
				_particleSystem.randomSeed = _randomSeed;
				ParticleSystem.MainModule mainModule = _particleSystem.main;
				mainModule.simulationSpeed = Sequence.Speed;
			}
			else
			{
#if UNITY_EDITOR
				Debug.LogError("FParticleEvent is attached to an object that doesn't have a ParticleSystem");
#endif
			}
			_previousTimeSinceTrigger = 0;
			_previousSpeed = Sequence.Speed;
		}

		protected override void OnTrigger( float timeSinceTrigger )
		{
            if (_particleSystem != null && Sequence.IsPlaying && Sequence.IsPlayingForward)
                _particleSystem.Play( true );
		}

		protected override void OnFinish()
		{
			if( _particleSystem != null )
				_particleSystem.Stop( true );
		}

		protected override void OnStop()
		{
			if( _particleSystem != null )
			{
				_particleSystem.Stop(true);
				_particleSystem.Clear( true );
			}
		}

		protected override void OnPause ()
		{
			if( _particleSystem != null )
				_particleSystem.Pause();
		}

		protected override void OnResume ()
		{
			if( _particleSystem != null && Sequence.IsPlayingForward )
				_particleSystem.Play(true);
		}

		protected override void OnUpdateEvent( float timeSinceTrigger )
		{
			if( _particleSystem == null )
				return;
			if( !Sequence.IsPlaying || !Sequence.IsPlayingForward )
			{
				_previousSpeed = 1;
				ParticleSystem.MainModule mainModule = _particleSystem.main;
				mainModule.simulationSpeed = _previousSpeed;
				float delta = timeSinceTrigger - _previousTimeSinceTrigger;
				_previousTimeSinceTrigger = timeSinceTrigger;
				if( Sequence.IsPlayingForward && delta > 0 )
				{
					_particleSystem.Simulate( delta, true, false );
				}
				else
				{
					float t = _normalizeToEventLength ? (timeSinceTrigger / LengthTime) * _particleSystem.main.duration : Mathf.Clamp(timeSinceTrigger, 0, _particleSystem.main.duration);
					_particleSystem.Simulate( t, true, true );
				}
			}
			else if( _previousSpeed != Sequence.Speed )
			{
				_previousSpeed = Sequence.Speed;
				ParticleSystem.MainModule mainModule = _particleSystem.main;
				mainModule.simulationSpeed = Mathf.Abs(_previousSpeed);
			}
		}
	}
}