fix: Support for skipping "reload domain"

close #406

Packages/manifest.json

@@ -3,7 +3,7 @@
     "com.coffee.development": "https://github.com/mob-sakai/Coffee.Internal.git?path=Packages/Development",
     "com.coffee.minimal-resource": "https://github.com/mob-sakai/Coffee.Internal.git?path=Packages/MinimalResource",
     "com.coffee.nano-monitor": "https://github.com/mob-sakai/Coffee.Internal.git?path=Packages/NanoMonitor",
-    "com.unity.ide.rider": "3.0.31",
+    "com.unity.ide.rider": "3.0.36",
     "com.unity.test-framework": "1.1.33",
     "com.unity.modules.animation": "1.0.0",
     "com.unity.modules.physics": "1.0.0"

Packages/packages-lock.json

@@ -40,7 +40,7 @@
       "url": "https://packages.unity.com"
     },
     "com.unity.ide.rider": {
-      "version": "3.0.31",
+      "version": "3.0.36",
       "depth": 0,
       "source": "registry",
       "dependencies": {

Packages/src/Editor/UIParticleEditor.cs

@@ -1,3 +1,4 @@
+using System;
 using System.Collections.Generic;
 using System.Linq;
 using System.Text.RegularExpressions;
@@ -8,12 +9,11 @@ using UnityEngine;
 using UnityEngine.Profiling;
 using UnityEngine.UI;
 using Coffee.UIParticleInternal;
+using Object = UnityEngine.Object;
 #if UNITY_2021_2_OR_NEWER
 using UnityEditor.Overlays;
 #else
-using System;
 using System.Reflection;
-using Object = UnityEngine.Object;
 #endif
 #if UNITY_2021_2_OR_NEWER
 using UnityEditor.SceneManagement;
@@ -66,6 +66,7 @@ namespace Coffee.UIExtensions
         private ReorderableList _ro;
         private bool _showMax;
         private bool _is3DScaleMode;
+        private GameObject[] _gameObjects;
 
         private static readonly HashSet<Shader> s_Shaders = new HashSet<Shader>();
 #if UNITY_2018 || UNITY_2019
@@ -183,6 +184,13 @@ namespace Coffee.UIExtensions
                                  y.hasMultipleDifferentValues ||
                                  z.hasMultipleDifferentValues;
             }
+
+            // Add temporary ParticleSystem for preview if enabled.
+            if (UIParticleProjectSettings.s_PreviewOnSelectOnSelect)
+            {
+                _gameObjects = targets.OfType<UIParticle>().Select(x => x.gameObject).ToArray();
+                ParticleSystemPreviewSystem.Register(_gameObjects);
+            }
         }
 
         /// <summary>
@@ -197,7 +205,10 @@ namespace Coffee.UIExtensions
             serializedObject.Update();
 
             // Maskable
+            if (_maskable != null)
+            {
                 EditorGUILayout.PropertyField(_maskable);
+            }
 
             // Scale
             EditorGUI.BeginDisabledGroup(!_meshSharing.hasMultipleDifferentValues && _meshSharing.intValue == 4);
@@ -344,6 +355,10 @@ namespace Coffee.UIExtensions
                 }
             }
 #endif
+
+            // Remove the temporary ParticleSystem.
+            ParticleSystemPreviewSystem.DrawWarningForTemporary(_gameObjects);
+
             Profiler.EndSample();
         }
 
@@ -482,7 +497,7 @@ namespace Coffee.UIExtensions
 #endif
         }
 
-        private static bool FixButton(bool show, string text)
+        private static bool FixButton(bool show, string text, GUIContent buttonText = null)
         {
             if (!show) return false;
             using (new EditorGUILayout.HorizontalScope(GUILayout.ExpandWidth(true)))
@@ -490,7 +505,7 @@ namespace Coffee.UIExtensions
                 EditorGUILayout.HelpBox(text, MessageType.Warning, true);
                 using (new EditorGUILayout.VerticalScope())
                 {
-                    return GUILayout.Button(s_ContentFix, GUILayout.Width(30));
+                    return GUILayout.Button(buttonText ?? s_ContentFix, GUILayout.ExpandWidth(false));
                 }
             }
         }

Packages/src/README.md

@@ -183,9 +183,14 @@ _This package requires **Unity 2018.3 or later**._
 - **Time Scale Multiplier:** Time scale multiplier.
 - **Rendering Order**: The ParticleSystem list to be rendered. You can change the order and the materials.
 
-**NOTE:** Press the `Refresh` button to reconstruct the rendering order based on children ParticleSystem's sorting order
+> [!TIPS]
+> Press the `Refresh` button to reconstruct the rendering order based on children ParticleSystem's sorting order
 and z-position.
 
+> [!TIPS]
+> When a `GameObject` with this component is selected in the editor, a temporary `ParticleSystem` is added if needed so you can preview the effect in the Scene view.
+> The generated `ParticleSystem` is marked with `HideFlags.DontSave`, so it is neither saved nor included in builds.
+
 <br><br>
 
 ### Basic Usage
@@ -195,6 +200,10 @@ and z-position.
 2. Adjust the ParticleSystem as you like.
    ![particle1](https://user-images.githubusercontent.com/12690315/95007359-ca385200-0649-11eb-8383-627c9750bda8.png)
 
+> [!Tips]
+> Adding a `UIParticle` to the parent is the recommended setup rather than attaching it directly to the `ParticleSystem`.
+> When using `ParticleSystem.emission.rateOverDistance`, it is recommended to move the transform of `UIParticle` rather than the `ParticleSystem`.
+
 <br>
 
 ### Usage with Your Existing ParticleSystem Prefab
@@ -256,13 +265,34 @@ uiParticle.Stop();
     - **Unscaled Time:** Update with unscaled delta time.
 - **OnAttracted**: An event called when attracting is complete (per particle).
 
+
+<br><br>
+
+### Component: ParticleSystemPreviewer
+
+`ParticleSystemPreviewer` is used to preview a ParticleSystem in the editor.
+
+- When a `GameObject` with this component is selected in the editor, a temporary `ParticleSystem` is added if needed so you can preview the effect in the Scene view.
+- The generated `ParticleSystem` is marked with `HideFlags.DontSave`, so it is neither saved nor included in builds.
+
+
 <br><br>
 
 ### Project Settings
 
-![](https://github.com/user-attachments/assets/befc7f34-fb47-4006-831a-eba79fda11ca)
+You can adjust the project-wide settings for `UI Particle`. (`Edit > Project Settings > UI > UI Particle`)
 
-- Click `Edit > Project Settings` to open the Project Settings window and then select `UI > UI Particle` category.
+![](https://github.com/mob-sakai/mob-sakai/releases/download/docs/1782270746550.png)
+
+#### Settings
+
+- **Enable Linear To Gamma**: Automatically correct the color space of the mesh.
+
+#### Editor
+
+- **Hide Generated Component**: Automatically hide the generated `UIParticleRenderer` component and `UIParticle BakingCamera`.
+
+- **Preview On Select**: When selecting UIParticle, a temporary ParticleSystem is generated for preview.
 
 <br><br>
 

Packages/src/Runtime/Internal/Extensions/CanvasExtensions.cs

@@ -98,7 +98,7 @@ namespace Coffee.UIParticleInternal
             Profiler.BeginSample("(COF)[CanvasExt] GetViewProjectionMatrix");
             var rootCanvas = canvas.rootCanvas;
             var cam = rootCanvas.worldCamera;
-            if (rootCanvas && rootCanvas.renderMode != RenderMode.ScreenSpaceOverlay && cam)
+            if (rootCanvas != null && rootCanvas.renderMode != RenderMode.ScreenSpaceOverlay && cam != null)
             {
                 if (eye == Camera.MonoOrStereoscopicEye.Mono)
                 {

Packages/src/Runtime/Internal/Extensions/ComponentExtensions.cs

@@ -12,6 +12,33 @@ namespace Coffee.UIParticleInternal
     /// </summary>
     internal static class ComponentExtensions
     {
+#if !UNITY_2019_2_OR_NEWER
+        public static bool TryGetComponent<T>(this GameObject self, out T component)
+            where T : Component
+        {
+            if (self == null)
+            {
+                component = null;
+                return false;
+            }
+
+            component = self.GetComponent<T>();
+            return component != null;
+        }
+
+        public static bool TryGetComponent<T>(this Component self, out T component)
+            where T : Component
+        {
+            if (self == null)
+            {
+                component = null;
+                return false;
+            }
+
+            return self.gameObject.TryGetComponent(out component);
+        }
+#endif
+
         /// <summary>
         /// Get components in children of a specific type in the hierarchy of a GameObject.
         /// </summary>
@@ -72,7 +99,7 @@ namespace Coffee.UIParticleInternal
         {
             T component = null;
             var transform = self.transform;
-            while (transform)
+            while (transform != null)
             {
                 if (transform.TryGetComponent<T>(out var c))
                 {
@@ -93,7 +120,7 @@ namespace Coffee.UIParticleInternal
             where T : Component
         {
             var tr = includeSelf ? self.transform : self.transform.parent;
-            while (tr)
+            while (tr != null)
             {
                 if (tr.TryGetComponent<T>(out var c) && valid(c)) return c;
                 if (tr == stopAfter) return null;
@@ -170,7 +197,7 @@ namespace Coffee.UIParticleInternal
             if (!includeInactive) return self.GetComponentInParent<T>();
 
             var current = self.transform;
-            while (current)
+            while (current != null)
             {
                 if (current.TryGetComponent<T>(out var c)) return c;
                 current = current.parent;

Packages/src/Runtime/Internal/ProjectSettings/PreloadedProjectSettings.cs

@@ -14,22 +14,66 @@ namespace Coffee.UIParticleInternal
     public abstract class PreloadedProjectSettings : ScriptableObject
 #if UNITY_EDITOR
     {
-        private class Postprocessor : AssetPostprocessor
+        [Tooltip("When enabled, this settings asset will be added to PlayerSettings.preloadedAssets in build.\n\n" +
+                 "When disable, you should load this settings via Resources, AssetBundles or Addressables to use.")]
+        [SerializeField]
+        [Header("Advanced")]
+        [HideInInspector]
+        private bool m_PreLoadSettingsInBuild = true;
+
+        protected static bool s_BuildingPlayer;
+
+        private class EditorEvents : AssetPostprocessor, IPreprocessBuildWithReport, IPostprocessBuildWithReport
         {
+            int IOrderedCallback.callbackOrder => 0;
+
             private static void OnPostprocessAllAssets(string[] _, string[] __, string[] ___, string[] ____)
             {
                 Initialize();
             }
-        }
-
-        private class PreprocessBuildWithReport : IPreprocessBuildWithReport
-        {
-            int IOrderedCallback.callbackOrder => 0;
 
             void IPreprocessBuildWithReport.OnPreprocessBuild(BuildReport report)
             {
+                AssetDatabase.Refresh();
+                Initialize();
+                s_BuildingPlayer = true;
+
+                foreach (var t in TypeCache.GetTypesDerivedFrom(typeof(PreloadedProjectSettings<>)))
+                {
+                    var settings = GetDefaultSettings(t);
+                    if (settings == null || settings.m_PreLoadSettingsInBuild) continue;
+
+                    PlayerSettings.SetPreloadedAssets(
+                        PlayerSettings.GetPreloadedAssets()
+                            .Where(x => x != null && x.GetType() != t)
+                            .ToArray());
+
+                    Debug.Log($"[PreloadedProjectSettings] Build started: removed '{settings.name}' " +
+                              $"({t.Name}) from PreloadedAssets. " +
+                              $"It will be restored after build completes.");
+                }
+            }
+
+            void IPostprocessBuildWithReport.OnPostprocessBuild(BuildReport report)
+            {
+                s_BuildingPlayer = false;
                 Initialize();
             }
+
+#if UNITY_2019_3_OR_NEWER
+            [RuntimeInitializeOnLoadMethod(RuntimeInitializeLoadType.SubsystemRegistration)]
+            private static void OnDomainReload()
+            {
+                foreach (var t in TypeCache.GetTypesDerivedFrom(typeof(PreloadedProjectSettings<>)))
+                {
+                    var defaultSettings = GetDefaultSettings(t);
+                    if (defaultSettings != null)
+                    {
+                        defaultSettings.OnDomainReload();
+                    }
+                }
+            }
+#endif
         }
 
         private static void Initialize()
@@ -38,14 +82,17 @@ namespace Coffee.UIParticleInternal
             {
                 var defaultSettings = GetDefaultSettings(t);
                 if (defaultSettings == null)
+                {
+                    if (!s_BuildingPlayer)
                     {
                         // When create a new instance, automatically set it as default settings.
                         defaultSettings = CreateInstance(t) as PreloadedProjectSettings;
                         SetDefaultSettings(defaultSettings);
                     }
+                }
                 else if (GetPreloadedSettings(t).Length != 1)
                 {
-                    SetDefaultSettings(defaultSettings);
+                    if (!s_BuildingPlayer) SetDefaultSettings(defaultSettings);
                 }
 
                 if (defaultSettings != null)
@@ -73,7 +120,7 @@ namespace Coffee.UIParticleInternal
         protected static PreloadedProjectSettings GetDefaultSettings(Type type)
         {
             return GetPreloadedSettings(type).FirstOrDefault() as PreloadedProjectSettings
-                   ?? AssetDatabase.FindAssets($"t:{nameof(PreloadedProjectSettings)}")
+                   ?? AssetDatabase.FindAssets($"t:{type.Name}")
                        .Select(AssetDatabase.GUIDToAssetPath)
                        .Select(AssetDatabase.LoadAssetAtPath<PreloadedProjectSettings>)
                        .FirstOrDefault(x => x != null && x.GetType() == type);
@@ -119,6 +166,39 @@ namespace Coffee.UIParticleInternal
         protected virtual void OnInitialize()
         {
         }
+
+        protected virtual void OnDomainReload()
+        {
+        }
+    }
+
+    internal abstract class PreloadedProjectSettingsEditor : Editor
+    {
+        private SerializedProperty _preLoadSettingsInBuild;
+
+        protected virtual void OnEnable()
+        {
+            _preLoadSettingsInBuild = serializedObject.FindProperty("m_PreLoadSettingsInBuild");
+        }
+
+        protected void DrawPreLoadSettingsInBuild(string packageName)
+        {
+            EditorGUILayout.PropertyField(_preLoadSettingsInBuild);
+            if (!_preLoadSettingsInBuild.boolValue)
+            {
+                EditorGUILayout.BeginHorizontal();
+                EditorGUILayout.HelpBox(
+                    $"{target.GetType().Name} asset will not be built in.\n" +
+                    $"please load manually from Resources, AssetBundle, or Addressables before using {packageName}.",
+                    MessageType.Warning);
+                if (GUILayout.Button("Ping"))
+                {
+                    EditorGUIUtility.PingObject(target);
+                }
+
+                EditorGUILayout.EndHorizontal();
+            }
+        }
     }
 #else
     {
@@ -151,14 +231,14 @@ namespace Coffee.UIParticleInternal
                     return s_Instance;
                 }
 
-                SetDefaultSettings(s_Instance);
+                if (!s_BuildingPlayer) SetDefaultSettings(s_Instance);
                 return s_Instance;
             }
         }
 
         private void OnPlayModeStateChanged(PlayModeStateChange state)
         {
-            if (!this) return;
+            if (this == null) return;
 
             switch (state)
             {
@@ -175,6 +255,11 @@ namespace Coffee.UIParticleInternal
                     break;
             }
         }
+
+        protected override void OnDomainReload()
+        {
+            s_Instance = null;
+        }
 #else
         public static T instance => s_Instance != null ? s_Instance : s_Instance = CreateInstance<T>();
 #endif
@@ -192,10 +277,14 @@ namespace Coffee.UIParticleInternal
                 return;
             }
 
+            EditorApplication.playModeStateChanged -= OnPlayModeStateChanged;
             EditorApplication.playModeStateChanged += OnPlayModeStateChanged;
+#else
+            if (s_Instance != null && s_Instance != this)
+            {
+                Destroy(s_Instance);
+            }
 #endif
-
-            if (s_Instance != null) return;
             s_Instance = this as T;
         }
 
@@ -226,7 +315,7 @@ namespace Coffee.UIParticleInternal
             {
                 if (_target == null)
                 {
-                    if (_editor)
+                    if (_editor != null)
                     {
                         DestroyImmediate(_editor);
                         _editor = null;

Packages/src/Runtime/Internal/Utilities/FastAction.cs

@@ -66,11 +66,6 @@ namespace Coffee.UIParticleInternal
                 node = node.Next;
             }
         }
-
-        public void Clear()
-        {
-            _delegates.Clear();
-        }
     }
 
     /// <summary>

Packages/src/Runtime/Internal/Utilities/FrameCache.cs

@@ -8,19 +8,19 @@ namespace Coffee.UIParticleInternal
     {
         private static readonly Dictionary<Type, IFrameCache> s_Caches = new Dictionary<Type, IFrameCache>();
 
-        static FrameCache()
+#if UNITY_EDITOR && UNITY_2019_3_OR_NEWER
-        {
-            s_Caches.Clear();
-            UIExtraCallbacks.onLateAfterCanvasRebuild += ClearAllCache;
-        }
-
-#if UNITY_EDITOR
         [RuntimeInitializeOnLoadMethod(RuntimeInitializeLoadType.SubsystemRegistration)]
+#elif UNITY_EDITOR
+        [InitializeOnLoadMethod]
+#else
+        [RuntimeInitializeOnLoadMethod(RuntimeInitializeLoadType.BeforeSceneLoad)]
+#endif
         private static void Clear()
         {
             s_Caches.Clear();
+            UIExtraCallbacks.onLateAfterCanvasRebuild -= ClearAllCache;
+            UIExtraCallbacks.onLateAfterCanvasRebuild += ClearAllCache;
         }
-#endif
 
         /// <summary>
         /// Tries to retrieve a value from the frame cache with a specified key.

Packages/src/Runtime/Internal/Utilities/Logger.cs.meta

@@ -1,2 +1,11 @@
 fileFormatVersion: 2
 guid: 4f9f22bb079324476b1473030ad9fec3
+MonoImporter:
+  externalObjects: {}
+  serializedVersion: 2
+  defaultReferences: []
+  executionOrder: 0
+  icon: {instanceID: 0}
+  userData: 
+  assetBundleName: 
+  assetBundleVariant: 

Packages/src/Runtime/Internal/Utilities/MaterialRepository.cs

@@ -13,7 +13,9 @@ namespace Coffee.UIParticleInternal
 
         public static int count => s_Repository.count;
 
-#if UNITY_EDITOR
+        public static Func<string, Shader> onShaderFind = Shader.Find;
+
+#if UNITY_EDITOR && UNITY_2019_3_OR_NEWER
         [RuntimeInitializeOnLoadMethod(RuntimeInitializeLoadType.SubsystemRegistration)]
         public static void Clear()
         {
@@ -48,7 +50,7 @@ namespace Coffee.UIParticleInternal
         public static void Get(Hash128 hash, ref Material material, string shaderName)
         {
             Profiler.BeginSample("(COF)[MaterialRepository] Get");
-            s_Repository.Get(hash, ref material, x => new Material(Shader.Find(x))
+            s_Repository.Get(hash, ref material, x => new Material(onShaderFind(x))
             {
                 hideFlags = HideFlags.DontSave | HideFlags.NotEditable
             }, shaderName);
@@ -61,7 +63,7 @@ namespace Coffee.UIParticleInternal
         public static void Get(Hash128 hash, ref Material material, string shaderName, string[] keywords)
         {
             Profiler.BeginSample("(COF)[MaterialRepository] Get");
-            s_Repository.Get(hash, ref material, x => new Material(Shader.Find(x.shaderName))
+            s_Repository.Get(hash, ref material, x => new Material(onShaderFind(x.shaderName))
             {
                 hideFlags = HideFlags.DontSave | HideFlags.NotEditable,
                 shaderKeywords = x.keywords

Packages/src/Runtime/Internal/Utilities/Misc.cs

@@ -48,15 +48,10 @@ namespace Coffee.UIParticleInternal
         {
             if (obj == null) return;
 #if UNITY_EDITOR
-            if (Application.isEditor)
+            Object.DestroyImmediate(obj, true);
-            {
+#else
-                Object.DestroyImmediate(obj);
-            }
-            else
-#endif
-            {
             Object.Destroy(obj);
-            }
+#endif
         }
 
         [Conditional("UNITY_EDITOR")]
@@ -114,7 +109,7 @@ namespace Coffee.UIParticleInternal
         {
             if (Misc.isBatchOrBuilding) return;
 
-            var types = TypeCache.GetTypesWithAttribute<IconAttribute>();
+            var types = TypeCache.GetTypesWithAttribute(typeof(IconAttribute));
             var scripts = MonoImporter.GetAllRuntimeMonoScripts();
             foreach (var type in types)
             {

Packages/src/Runtime/Internal/Utilities/TypeCache.cs

@@ -0,0 +1,88 @@
+#if !UNITY_2019_2_OR_NEWER
+using System;
+using System.Collections.Generic;
+using System.Reflection;
+
+namespace Coffee.UIParticleInternal
+{
+    public static class TypeCache
+    {
+        private static readonly object s_Lock = new object();
+        private static readonly Dictionary<Type, Type[]> s_DerivedTypesCache = new Dictionary<Type, Type[]>();
+        private static readonly Dictionary<Type, Type[]> s_AttributeTypesCache = new Dictionary<Type, Type[]>();
+
+        public static IEnumerable<Type> GetTypesDerivedFrom(Type baseType)
+        {
+            lock (s_Lock)
+            {
+                if (s_DerivedTypesCache.TryGetValue(baseType, out var cached))
+                {
+                    return cached;
+                }
+
+                var types = new List<Type>();
+                foreach (var t in GetAllLoadableTypes())
+                {
+                    if (t != baseType && baseType.IsAssignableFrom(t))
+                    {
+                        types.Add(t);
+                    }
+                }
+
+                return s_DerivedTypesCache[baseType] = types.ToArray();
+            }
+        }
+
+        public static IEnumerable<Type> GetTypesWithAttribute(Type attr)
+        {
+            lock (s_Lock)
+            {
+                if (s_AttributeTypesCache.TryGetValue(attr, out var cached))
+                {
+                    return cached;
+                }
+
+                var types = new List<Type>();
+                foreach (var t in GetAllLoadableTypes())
+                {
+                    if (t.GetCustomAttributes(attr, inherit: true).Length > 0)
+                    {
+                        types.Add(t);
+                    }
+                }
+
+                return s_AttributeTypesCache[attr] = types.ToArray();
+            }
+        }
+
+        private static IEnumerable<Type> GetAllLoadableTypes()
+        {
+            foreach (var assembly in AppDomain.CurrentDomain.GetAssemblies())
+            {
+                Type[] types;
+                try
+                {
+                    types = assembly.GetTypes();
+                }
+                catch (ReflectionTypeLoadException ex)
+                {
+                    types = ex.Types;
+                }
+
+                if (types == null)
+                {
+                    continue;
+                }
+
+                foreach (var t in types)
+                {
+                    if (t != null)
+                    {
+                        yield return t;
+                    }
+                }
+            }
+        }
+    }
+}
+#endif

Packages/src/Runtime/Internal/Utilities/TypeCache.cs.meta

@@ -0,0 +1,11 @@
+fileFormatVersion: 2
+guid: bc1207b657ed74ec19e459664d06925f
+MonoImporter:
+  externalObjects: {}
+  serializedVersion: 2
+  defaultReferences: []
+  executionOrder: 0
+  icon: {instanceID: 0}
+  userData: 
+  assetBundleName: 
+  assetBundleVariant: 

Packages/src/Runtime/Internal/Utilities/UIExtraCallbacks.cs

@@ -82,14 +82,18 @@ namespace Coffee.UIParticleInternal
                 message: "InitializeAfterCanvasRebuild");
         }
 
-#if UNITY_EDITOR
+#if UNITY_EDITOR && UNITY_2019_3_OR_NEWER
+        [RuntimeInitializeOnLoadMethod(RuntimeInitializeLoadType.SubsystemRegistration)]
+#elif UNITY_EDITOR
         [InitializeOnLoadMethod]
-#endif
+#else
         [RuntimeInitializeOnLoadMethod(RuntimeInitializeLoadType.BeforeSceneLoad)]
+#endif
         private static void InitializeOnLoad()
         {
             Canvas.willRenderCanvases -= OnAfterCanvasRebuild;
             s_IsInitializedAfterCanvasRebuild = false;
+            s_LastScreenSize = default;
         }
 
         /// <summary>

Packages/src/Runtime/ParticleSystemPreviewer.cs

@@ -0,0 +1,237 @@
+using System.Collections.Generic;
+using System.Linq;
+using Coffee.UIParticleInternal;
+using UnityEditor;
+using UnityEngine;
+
+namespace Coffee.UIExtensions
+{
+    [Icon("Packages/com.coffee.ui-particle/Editor/UIParticleIcon.png")]
+    [ExecuteAlways]
+    internal class ParticleSystemPreviewer : MonoBehaviour
+    {
+        // Do nothing.
+    }
+
+#if UNITY_EDITOR
+    [CustomEditor(typeof(ParticleSystemPreviewer))]
+    [CanEditMultipleObjects]
+    internal class ParticleSystemPreviewerEditor : Editor
+    {
+        private GameObject[] _gameObjects;
+
+        private void OnEnable()
+        {
+            _gameObjects = targets.OfType<ParticleSystemPreviewer>().Select(x => x.gameObject).ToArray();
+            ParticleSystemPreviewSystem.Register(_gameObjects);
+        }
+
+        public override void OnInspectorGUI()
+        {
+            base.OnInspectorGUI();
+            ParticleSystemPreviewSystem.DrawWarningForTemporary(_gameObjects);
+            ParticleSystemPreviewSystem.DrawWarningForPermanent(_gameObjects);
+        }
+    }
+
+    /// <summary>
+    /// This class manages temporary ParticleSystems for preview purposes.
+    /// When previewing in the editor, it is common to place an empty ParticleSystem as the root, but it consumes memory at runtime if included in the build.
+    /// The temporary ParticleSystems created by this class only exist when the specified GameObject is selected, and are automatically deleted when the selection is cleared.
+    /// </summary>
+    internal class ParticleSystemPreviewSystem : ScriptableSingleton<ParticleSystemPreviewSystem>
+    {
+        private const HideFlags k_TemporaryHideFlags = HideFlags.DontSave | HideFlags.NotEditable;
+
+        [SerializeField]
+        private List<GameObject> m_PreviewObjects = new List<GameObject>();
+
+#if UNITY_2019_3_OR_NEWER
+        [RuntimeInitializeOnLoadMethod(RuntimeInitializeLoadType.SubsystemRegistration)]
+#endif
+        [InitializeOnLoadMethod]
+        public static void Initialize()
+        {
+            instance.OnSelectionChanged();
+
+            Selection.selectionChanged -= instance.OnSelectionChanged;
+            Selection.selectionChanged += instance.OnSelectionChanged;
+        }
+
+        /// <summary>
+        /// Adds a temporary ParticleSystem to the specified GameObject for preview purposes.
+        /// </summary>
+        public static void Register(GameObject[] targets)
+        {
+            foreach (var target in targets)
+            {
+                Register(target);
+            }
+        }
+
+        /// <summary>
+        /// Adds a temporary ParticleSystem to the specified GameObject for preview purposes.
+        /// </summary>
+        public static void Register(GameObject target)
+        {
+            if (!target) return;
+            if (EditorApplication.isPlaying) return;
+            if (instance.m_PreviewObjects.Contains(target)) return;
+            if (target.TryGetComponent<ParticleSystem>(out var ps))
+            {
+                if (ps.hideFlags == k_TemporaryHideFlags)
+                {
+                    RegisterParticleSystem(ps);
+                }
+
+                return;
+            }
+
+            // Create temporary ParticleSystem for preview.
+            RegisterParticleSystem(target.AddComponent<ParticleSystem>());
+        }
+
+        /// <summary>
+        /// Removes the temporary ParticleSystem associated with the specified GameObject.
+        /// </summary>
+        /// <param name="target"></param>
+        public static void Unregister(GameObject target)
+        {
+            if (!target) return;
+
+            var index = instance.m_PreviewObjects.IndexOf(target);
+            if (index < 0) return;
+
+            instance.m_PreviewObjects.RemoveAt(index);
+            if (HasTemporaryParticleSystem(target))
+            {
+                RemoveParticleSystem(target);
+            }
+        }
+
+        private static void RegisterParticleSystem(ParticleSystem ps)
+        {
+            if (!ps) return;
+            if (EditorApplication.isPlaying) return;
+
+            ps.hideFlags = k_TemporaryHideFlags;
+
+            var emission = ps.emission;
+            emission.enabled = false;
+            var shape = ps.shape;
+            shape.enabled = false;
+
+            if (ps.TryGetComponent<ParticleSystemRenderer>(out var psr))
+            {
+                psr.enabled = false;
+                psr.hideFlags = k_TemporaryHideFlags;
+            }
+
+            instance.m_PreviewObjects.Add(ps.gameObject);
+            EditorUtility.SetDirty(ps.gameObject);
+        }
+
+        /// <summary>
+        /// Removes the temporary ParticleSystem associated with the specified GameObject.
+        /// </summary>
+        /// <param name="target"></param>
+        private static void RemoveParticleSystem(GameObject target)
+        {
+            if (target.TryGetComponent<ParticleSystem>(out var ps))
+            {
+                Misc.DestroyImmediate(ps);
+                EditorUtility.SetDirty(target);
+            }
+
+            if (target.TryGetComponent<ParticleSystem>(out var psr))
+            {
+                Misc.DestroyImmediate(psr);
+                EditorUtility.SetDirty(target);
+            }
+        }
+
+        /// <summary>
+        /// Checks if the specified GameObject has a temporary ParticleSystem.
+        /// </summary>
+        private static bool HasTemporaryParticleSystem(GameObject target)
+        {
+            return target
+                   && instance.m_PreviewObjects.Contains(target)
+                   && target.TryGetComponent<ParticleSystem>(out var ps)
+                   && ps.hideFlags == k_TemporaryHideFlags;
+        }
+
+        /// <summary>
+        /// Checks if the specified GameObject has a permanent ParticleSystem.
+        /// </summary>
+        private static bool HasPermanentParticleSystem(GameObject target)
+        {
+            return target
+                   && target.TryGetComponent<ParticleSystem>(out var ps)
+                   && ps.hideFlags != k_TemporaryHideFlags;
+        }
+
+        private void OnSelectionChanged()
+        {
+            var selectedGameObjects = Selection.gameObjects;
+            for (var i = m_PreviewObjects.Count - 1; 0 <= i; i--)
+            {
+                var go = m_PreviewObjects[i];
+                if (!go)
+                {
+                    m_PreviewObjects.RemoveAt(i);
+                }
+                else if (EditorApplication.isPlaying && !selectedGameObjects.Contains(go))
+                {
+                    Unregister(go);
+                }
+            }
+        }
+
+        public static void DrawWarningForTemporary(GameObject[] gameObjects)
+        {
+            if (gameObjects == null || gameObjects.Length == 0 || !gameObjects.Any(HasTemporaryParticleSystem)) return;
+
+            if (WarningButton("The temporary ParticleSystem for preview is attached.\n" +
+                              "It will be removed when exiting edit mode.", "Remove"))
+            {
+                foreach (var go in gameObjects)
+                {
+                    if (HasTemporaryParticleSystem(go))
+                    {
+                        RemoveParticleSystem(go);
+                    }
+                }
+            }
+        }
+
+        public static void DrawWarningForPermanent(GameObject[] gameObjects)
+        {
+            if (gameObjects == null || gameObjects.Length == 0 || !gameObjects.Any(HasPermanentParticleSystem)) return;
+
+            if (WarningButton("The permanent ParticleSystem is attached.\n" +
+                              "It will be included in build.", "Remove"))
+            {
+                foreach (var go in gameObjects)
+                {
+                    if (HasPermanentParticleSystem(go))
+                    {
+                        RemoveParticleSystem(go);
+                        Unregister(go);
+                        Register(go);
+                    }
+                }
+            }
+        }
+
+        private static bool WarningButton(string message, string buttonText)
+        {
+            EditorGUILayout.BeginHorizontal();
+            EditorGUILayout.HelpBox(message, MessageType.Warning, true);
+            var clicked = GUILayout.Button(EditorGUIUtility.TrTempContent(buttonText));
+            EditorGUILayout.EndHorizontal();
+            return clicked;
+        }
+    }
+#endif
+}

Packages/src/Runtime/ParticleSystemPreviewer.cs.meta

@@ -0,0 +1,11 @@
+fileFormatVersion: 2
+guid: b171deb49fb7b471291108ad7e1c9baa
+MonoImporter:
+  externalObjects: {}
+  serializedVersion: 2
+  defaultReferences: []
+  executionOrder: 0
+  icon: {instanceID: 0}
+  userData: 
+  assetBundleName: 
+  assetBundleVariant: 

Packages/src/Runtime/UIParticle.cs

@@ -545,7 +545,10 @@ namespace Coffee.UIExtensions
             {
                 var ps = particles[i];
                 if (!ps
+#if UNITY_EDITOR
+                    || (ps.hideFlags & HideFlags.DontSave) != 0 // Dummy ParticleSystems for preview.
                     || ps.gameObject.CompareTag("EditorOnly") // Ignore "EditorOnly" tagged ParticleSystems.
+#endif
                     || ps.GetComponentInParent<UIParticle>(true) != this) // Ignore ParticleSystems that are not under this UIParticle.
                 {
                     particles.RemoveAt(i);

Packages/src/Runtime/UIParticleProjectSettings.cs

@@ -2,6 +2,7 @@
 using Coffee.UIParticleInternal;
 using UnityEditor;
 using UnityEngine;
+using UnityEngine.Serialization;
 
 namespace Coffee.UIExtensions
 {
@@ -9,12 +10,14 @@ namespace Coffee.UIExtensions
     {
         [Header("Setting")]
         [SerializeField]
-        internal bool m_EnableLinearToGamma = true;
+        [Tooltip("Automatically correct the color space of the mesh.")]
+        [FormerlySerializedAs("m_EnableLinearToGamma")]
+        internal bool m_AutoColorCorrection = true;
 
-        public static bool enableLinearToGamma
+        public static bool autoColorCorrection
         {
-            get => instance.m_EnableLinearToGamma;
+            get => instance.m_AutoColorCorrection;
-            set => instance.m_EnableLinearToGamma = value;
+            set => instance.m_AutoColorCorrection = value;
         }
 
 
@@ -25,10 +28,16 @@ namespace Coffee.UIExtensions
         [SerializeField]
         private bool m_HideGeneratedObjects = true;
 
-        public static HideFlags globalHideFlags => instance.m_HideGeneratedObjects
+        [Tooltip("When selecting UIParticle, a temporary ParticleSystem is generated for preview.")]
+        [SerializeField]
+        private bool m_PreviewOnSelect = true;
+
+        internal static HideFlags globalHideFlags => instance.m_HideGeneratedObjects
             ? HideFlags.DontSave | HideFlags.NotEditable | HideFlags.HideInHierarchy | HideFlags.HideInInspector
             : HideFlags.DontSave | HideFlags.NotEditable;
 
+        internal static bool s_PreviewOnSelectOnSelect => instance.m_PreviewOnSelect;
+
 #if UNITY_EDITOR
         [SettingsProvider]
         private static SettingsProvider CreateSettingsProvider()

Packages/src/Runtime/UIParticleRenderer.cs

@@ -444,7 +444,7 @@ namespace Coffee.UIExtensions
                 _lastBounds = bounds;
 
                 // Convert linear color to gamma color.
-                if (UIParticleProjectSettings.enableLinearToGamma && canvas.ShouldGammaToLinearInMesh())
+                if (UIParticleProjectSettings.autoColorCorrection && canvas.ShouldGammaToLinearInMesh())
                 {
                     workerMesh.LinearToGamma();
                 }

Packages/src/Runtime/UIParticleUpdater.cs

@@ -39,6 +39,17 @@ namespace Coffee.UIExtensions
         }
 
 #if UNITY_EDITOR
+#if UNITY_2019_3_OR_NEWER
+        [RuntimeInitializeOnLoadMethod(RuntimeInitializeLoadType.SubsystemRegistration)]
+        private static void OnDomainReload()
+        {
+            s_ActiveParticles.Clear();
+            s_ActiveAttractors.Clear();
+            s_UpdatedGroupIds.Clear();
+            s_FrameCount = 0;
+        }
+#endif
+
         [InitializeOnLoadMethod]
         private static void InitializeOnLoad()
         {

Packages/src/Shaders/UIAdditive.shader

@@ -40,12 +40,8 @@
         Lighting Off
         ZWrite Off
         ZTest [unity_GUIZTestMode]
-        Fog
+        Fog { Mode Off }
-        {
-            Mode Off
-        }
         Blend One One
-
         ColorMask [_ColorMask]
 
         Pass
@@ -76,6 +72,7 @@
                 fixed4 color : COLOR;
                 float2 texcoord : TEXCOORD0;
                 float4 worldPosition : TEXCOORD1;
+                float4 mask : TEXCOORD2;
                 UNITY_VERTEX_OUTPUT_STEREO
             };
 
@@ -84,16 +81,43 @@
             float4 _MainTex_ST;
             fixed4 _TextureSampleAdd;
             float4 _ClipRect;
+            float _UIMaskSoftnessX;
+            float _UIMaskSoftnessY;
+            int _UIVertexColorAlwaysGammaSpace;
+
+            half3 _UIGammaToLinear(half3 value)
+            {
+                half3 low = 0.0849710 * value - 0.000163029;
+                half3 high = value * (value * (value * 0.265885 + 0.736584) - 0.00980184) + 0.00319697;
+
+                // We should be 0.5 away from any actual gamma value stored in an 8 bit channel
+                const half3 split = (half3)0.0725490; // Equals 18.5 / 255
+                return (value < split) ? low : high;
+            }
 
             v2f vert(appdata_t v)
             {
                 v2f OUT;
                 UNITY_SETUP_INSTANCE_ID(v);
                 UNITY_INITIALIZE_VERTEX_OUTPUT_STEREO(OUT);
+                float4 vPosition = UnityObjectToClipPos(v.vertex);
                 OUT.worldPosition = v.vertex;
-                OUT.vertex = UnityObjectToClipPos(OUT.worldPosition);
+                OUT.vertex = vPosition;
 
-                OUT.texcoord = TRANSFORM_TEX(v.texcoord, _MainTex);
+                float2 pixelSize = vPosition.w;
+                pixelSize /= float2(1, 1) * abs(mul((float2x2)UNITY_MATRIX_P, _ScreenParams.xy));
+
+                float4 clampedRect = clamp(_ClipRect, -2e10, 2e10);
+                float2 maskUV = (v.vertex.xy - clampedRect.xy) / (clampedRect.zw - clampedRect.xy);
+                OUT.texcoord = TRANSFORM_TEX(v.texcoord.xy, _MainTex);
+                OUT.mask = float4(v.vertex.xy * 2 - clampedRect.xy - clampedRect.zw, 0.25 / (0.25 * half2(_UIMaskSoftnessX, _UIMaskSoftnessY) + abs(pixelSize.xy)));
+
+                if (_UIVertexColorAlwaysGammaSpace)
+                {
+                    #ifndef UNITY_COLORSPACE_GAMMA
+                    v.color.rgb = _UIGammaToLinear(v.color.rgb);
+                    #endif
+                }
 
                 OUT.color = v.color * _Color;
                 return OUT;
@@ -101,10 +125,18 @@
 
             fixed4 frag(v2f IN) : SV_Target
             {
-                half4 color = (tex2D(_MainTex, IN.texcoord) + _TextureSampleAdd) * IN.color;
+                //Round up the alpha color coming from the interpolator (to 1.0/256.0 steps)
+                //The incoming alpha could have numerical instability, which makes it very sensible to
+                //HDR color transparency blend, when it blends with the world's texture.
+                const half alphaPrecision = half(0xff);
+                const half invAlphaPrecision = half(1.0 / alphaPrecision);
+                IN.color.a = round(IN.color.a * alphaPrecision) * invAlphaPrecision;
+
+                half4 color = IN.color * (tex2D(_MainTex, IN.texcoord) + _TextureSampleAdd);
 
                 #ifdef UNITY_UI_CLIP_RECT
-                    color.a *= UnityGet2DClipping(IN.worldPosition.xy, _ClipRect);
+                half2 m = saturate((_ClipRect.zw - _ClipRect.xy - abs(IN.mask.xy)) * IN.mask.zw);
+                color.a *= m.x * m.y;
                 #endif
 
                 #ifdef UNITY_UI_ALPHACLIP
@@ -112,6 +144,7 @@
                 #endif
 
                 color.rgb *= color.a;
+
                 return color;
             }
             ENDCG