Add some improvements to particles editing

#1395

Source/Editor/CustomEditors/Dedicated/ParticleEffectEditor.cs

@@ -25,9 +25,20 @@ namespace FlaxEditor.CustomEditors.Dedicated
             get
             {
                 // All selected particle effects use the same system
-                var effect = (ParticleEffect)Values[0];
-                var system = effect.ParticleSystem;
-                return system != null && Values.TrueForAll(x => (x as ParticleEffect)?.ParticleSystem == system);
+                var effect = Values[0] as ParticleEffect;
+                var system = effect ? effect.ParticleSystem : null;
+                if (system && Values.TrueForAll(x => x is ParticleEffect fx && fx && fx.ParticleSystem == system))
+                {
+                    // All parameters can be accessed
+                    var parameters = effect.Parameters;
+                    foreach (var parameter in parameters)
+                    {
+                        if (!parameter)
+                            return false;
+                    }
+                    return true;
+                }
+                return false;
             }
         }
 

Source/Engine/Particles/ParticleEffect.cpp

@@ -402,7 +402,7 @@ SceneRenderTask* ParticleEffect::GetRenderTask() const
 
 #if USE_EDITOR
 
-Array<ParticleEffect::ParameterOverride> ParticleEffect::GetParametersOverrides()
+Array<ParticleEffect::ParameterOverride>& ParticleEffect::GetParametersOverrides()
 {
     CacheModifiedParameters();
     return _parametersOverrides;
@@ -461,7 +461,6 @@ void ParticleEffect::CacheModifiedParameters()
 {
     if (_parameters.IsEmpty())
         return;
-
     _parametersOverrides.Clear();
     auto& parameters = GetParameters();
     for (auto& param : parameters)

Source/Engine/Particles/ParticleEffect.h

@@ -382,7 +382,7 @@ public:
 #if USE_EDITOR
 protected:
     // Exposed parameters overrides for Editor Undo.
-    API_PROPERTY(Attributes="HideInEditor, Serialize") Array<ParticleEffect::ParameterOverride> GetParametersOverrides();
+    API_PROPERTY(Attributes="HideInEditor, Serialize") Array<ParticleEffect::ParameterOverride>& GetParametersOverrides();
     API_PROPERTY() void SetParametersOverrides(const Array<ParticleEffect::ParameterOverride>& value);
 #endif