Added Play, pause, and stop functions to particle effect for more manual control if needed.

Source/Engine/Particles/ParticleEffect.cpp

@@ -275,6 +275,30 @@ void ParticleEffect::UpdateSimulation(bool singleFrame)
     Particles::UpdateEffect(this);
 }
 
+void ParticleEffect::Play(bool reset)
+{
+    _play = true;
+    IsPlaying = true;
+    
+    if (reset)
+        ResetSimulation();
+    else
+        UpdateSimulation(true);
+}
+
+void ParticleEffect::Pause()
+{
+    _play = false;
+    IsPlaying = false;
+}
+
+void ParticleEffect::Stop()
+{
+    _play = false;
+    IsPlaying = false;
+    ResetSimulation();
+}
+
 void ParticleEffect::UpdateBounds()
 {
     BoundingBox bounds = BoundingBox::Empty;
@@ -395,6 +419,9 @@ void ParticleEffect::SetParametersOverrides(const Array<ParameterOverride>& valu
 
 void ParticleEffect::Update()
 {
+    if (!_play)
+        return;
+    
     // Skip if off-screen
     if (!UpdateWhenOffscreen && _lastMinDstSqr >= MAX_Real)
         return;
@@ -417,7 +444,14 @@ void ParticleEffect::Update()
 void ParticleEffect::UpdateExecuteInEditor()
 {
     if (!Editor::IsPlayMode)
+    {
+        // Always Play in editor while not playing.
+        // Could be useful to have a GUI to change this state
+        if (!_play)
+            _play = true; 
+        
         Update();
+    }
 }
 
 #endif
@@ -576,6 +610,7 @@ void ParticleEffect::Serialize(SerializeStream& stream, const void* otherObj)
     SERIALIZE(SimulationSpeed);
     SERIALIZE(UseTimeScale);
     SERIALIZE(IsLooping);
+    SERIALIZE(PlayOnStart);
     SERIALIZE(UpdateWhenOffscreen);
     SERIALIZE(DrawModes);
     SERIALIZE(SortOrder);
@@ -675,6 +710,7 @@ void ParticleEffect::Deserialize(DeserializeStream& stream, ISerializeModifier*
     DESERIALIZE(SimulationSpeed);
     DESERIALIZE(UseTimeScale);
     DESERIALIZE(IsLooping);
+    DESERIALIZE(PlayOnStart);
     DESERIALIZE(UpdateWhenOffscreen);
     DESERIALIZE(DrawModes);
     DESERIALIZE(SortOrder);
@@ -685,6 +721,12 @@ void ParticleEffect::Deserialize(DeserializeStream& stream, ISerializeModifier*
     }
 }
 
+void ParticleEffect::BeginPlay(SceneBeginData* data)
+{
+    
+    Actor::BeginPlay(data);
+}
+
 void ParticleEffect::EndPlay()
 {
     CacheModifiedParameters();
@@ -706,6 +748,9 @@ void ParticleEffect::OnEnable()
     GetScene()->Ticking.Update.AddTickExecuteInEditor<ParticleEffect, &ParticleEffect::UpdateExecuteInEditor>(this);
 #endif
 
+    if (PlayOnStart)
+        Play();
+    
     // Base
     Actor::OnEnable();
 }

Source/Engine/Particles/ParticleEffect.h

@@ -184,6 +184,7 @@ private:
     uint32 _parametersVersion = 0; // Version number for _parameters to be in sync with Instance.ParametersVersion
     Array<ParticleEffectParameter> _parameters; // Cached for scripting API
     Array<ParameterOverride> _parametersOverrides; // Cached parameter modifications to be applied to the parameters
+    bool _play = false;
 
 public:
     /// <summary>
@@ -235,9 +236,21 @@ public:
     bool IsLooping = true;
 
     /// <summary>
-    /// If true, the particle simulation will be updated even when an actor cannot be seen by any camera. Otherwise, the simulation will stop running when the actor is off-screen.
+    /// Determines whether the particle effect should play on start.
     /// </summary>
     API_FIELD(Attributes="EditorDisplay(\"Particle Effect\"), DefaultValue(true), EditorOrder(60)")
+    bool PlayOnStart = true;
+
+    /// <summary>
+    /// If true, the particle effect is playing.
+    /// </summary>
+    API_FIELD()
+    bool IsPlaying = false;
+
+    /// <summary>
+    /// If true, the particle simulation will be updated even when an actor cannot be seen by any camera. Otherwise, the simulation will stop running when the actor is off-screen.
+    /// </summary>
+    API_FIELD(Attributes="EditorDisplay(\"Particle Effect\"), DefaultValue(true), EditorOrder(70)")
     bool UpdateWhenOffscreen = true;
 
     /// <summary>
@@ -337,6 +350,22 @@ public:
     /// <param name="singleFrame">True if update animation by a single frame only (time time since last engine update), otherwise will update simulation with delta time since last update.</param>
     API_FUNCTION() void UpdateSimulation(bool singleFrame = false);
 
+    /// <summary>
+    /// Plays the simulation.
+    /// </summary>
+    /// /// <param name="reset">If true, the simulation will be reset</param>
+    API_FUNCTION() void Play(bool reset = true);
+
+    /// <summary>
+    /// Pauses the simulation.
+    /// </summary>
+    API_FUNCTION() void Pause();
+
+    /// <summary>
+    /// Stops and resets the simulation.
+    /// </summary>
+    API_FUNCTION() void Stop();
+
     /// <summary>
     /// Updates the actor bounds.
     /// </summary>
@@ -389,6 +418,7 @@ public:
 
 protected:
     // [Actor]
+    void BeginPlay(SceneBeginData* data) override;
     void EndPlay() override;
     void OnEnable() override;
     void OnDisable() override;