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Source/Editor/Viewport/Previews/ParticleEmitterPreview.cs

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+// Copyright (c) 2012-2020 Wojciech Figat. All rights reserved.
+
+using FlaxEditor.GUI.Input;
+using FlaxEngine;
+using Object = FlaxEngine.Object;
+
+namespace FlaxEditor.Viewport.Previews
+{
+    /// <summary>
+    /// Particle Emitter asset preview editor viewport.
+    /// </summary>
+    /// <seealso cref="AssetPreview" />
+    public class ParticleEmitterPreview : ParticleSystemPreview
+    {
+        private ParticleEmitter _emitter;
+        private ParticleSystem _system;
+        private float _playbackDuration = 5.0f;
+
+        /// <summary>
+        /// Gets or sets the particle emitter asset to preview.
+        /// </summary>
+        public ParticleEmitter Emitter
+        {
+            get => _emitter;
+            set
+            {
+                if (_emitter != value)
+                {
+                    _emitter = value;
+                    _system.Init(value, _playbackDuration);
+                    PreviewActor.ResetSimulation();
+                }
+            }
+        }
+
+        /// <summary>
+        /// Gets or sets the duration of the emitter playback (in seconds).
+        /// </summary>
+        public float PlaybackDuration
+        {
+            get => _playbackDuration;
+            set
+            {
+                value = Mathf.Clamp(value, 0.1f, 100000000000.0f);
+                if (Mathf.NearEqual(_playbackDuration, value))
+                    return;
+
+                _playbackDuration = value;
+                if (_system != null)
+                {
+                    _system.Init(_emitter, _playbackDuration);
+                    PreviewActor.ResetSimulation();
+                }
+            }
+        }
+
+        /// <summary>
+        /// Initializes a new instance of the <see cref="ParticleEmitterPreview"/> class.
+        /// </summary>
+        /// <param name="useWidgets">if set to <c>true</c> use widgets.</param>
+        public ParticleEmitterPreview(bool useWidgets)
+        : base(useWidgets)
+        {
+            _system = FlaxEngine.Content.CreateVirtualAsset<ParticleSystem>();
+            System = _system;
+
+            if (useWidgets)
+            {
+                var playbackDuration = ViewWidgetButtonMenu.AddButton("Duration");
+                var playbackDurationValue = new FloatValueBox(_playbackDuration, 75, 2, 50.0f, 0.1f, 1000000.0f, 0.1f);
+                playbackDurationValue.Parent = playbackDuration;
+                playbackDurationValue.ValueChanged += () => PlaybackDuration = playbackDurationValue.Value;
+                ViewWidgetButtonMenu.VisibleChanged += control => playbackDurationValue.Value = PlaybackDuration;
+            }
+        }
+
+        /// <inheritdoc />
+        public override bool HasLoadedAssets => (_emitter == null || _emitter.IsLoaded) && base.HasLoadedAssets;
+
+        /// <inheritdoc />
+        public override void OnDestroy()
+        {
+            // Cleanup objects
+            _emitter = null;
+            Object.Destroy(ref _system);
+
+            base.OnDestroy();
+        }
+    }
+}