chore(release): 5.0.0-preview.2 [skip ci]

# [5.0.0-preview.2](https://github.com/mob-sakai/ParticleEffectForUGUI/compare/v5.0.0-preview.1...v5.0.0-preview.2) (2024-06-20)

### Bug Fixes

* 'Resource ID out of range in GetResource' error in overlay rendering mode ([ff78b6f](ff78b6fe32)), closes [#308](https://github.com/mob-sakai/ParticleEffectForUGUI/issues/308)
* `UIParticle.transform.localScale` does not scale particles ([491ee7b](491ee7b0c3)), closes [#313](https://github.com/mob-sakai/ParticleEffectForUGUI/issues/313)
* despite not using the size module, particles become smaller based on their z position ([c96ddf2](c96ddf293e)), closes [#316](https://github.com/mob-sakai/ParticleEffectForUGUI/issues/316)
* the ParticleSystem's localPosition drifts at certain scales due to floating-point precision issues ([a9c2b19](a9c2b19edf)), closes [#299](https://github.com/mob-sakai/ParticleEffectForUGUI/issues/299) [#312](https://github.com/mob-sakai/ParticleEffectForUGUI/issues/312)
* UIParticle is scaled by canvas size even when `AutoScalingMode.None` and `ScalingMode.Local` ([63b24d8](63b24d8a8b)), closes [#313](https://github.com/mob-sakai/ParticleEffectForUGUI/issues/313)
* UIParticle is scaled incorrectly with nested canvases ([c95d8c6](c95d8c6b17)), closes [#313](https://github.com/mob-sakai/ParticleEffectForUGUI/issues/313)

### Features

* remove overlay window (editor) ([fc3fbdd](fc3fbdd230))
* reset previous position on start play for world space simulation ([e741584](e741584507)), closes [#303](https://github.com/mob-sakai/ParticleEffectForUGUI/issues/303)
* restore `Transform.localScale` when setting `autoScalingMode` to something other than `Transform` ([dfb94f4](dfb94f4bad))

CHANGELOG.md

@@ -1,3 +1,22 @@
+# [5.0.0-preview.2](https://github.com/mob-sakai/ParticleEffectForUGUI/compare/v5.0.0-preview.1...v5.0.0-preview.2) (2024-06-20)
+
+
+### Bug Fixes
+
+* 'Resource ID out of range in GetResource' error in overlay rendering mode ([ff78b6f](https://github.com/mob-sakai/ParticleEffectForUGUI/commit/ff78b6fe32ceed8ddad50e63dcb7a202eab95266)), closes [#308](https://github.com/mob-sakai/ParticleEffectForUGUI/issues/308)
+* `UIParticle.transform.localScale` does not scale particles ([491ee7b](https://github.com/mob-sakai/ParticleEffectForUGUI/commit/491ee7b0c3e528e1e577ae5ff2588d7c3bd8ecdb)), closes [#313](https://github.com/mob-sakai/ParticleEffectForUGUI/issues/313)
+* despite not using the size module, particles become smaller based on their z position ([c96ddf2](https://github.com/mob-sakai/ParticleEffectForUGUI/commit/c96ddf293e855f7ebccaaaf3b112092955545e61)), closes [#316](https://github.com/mob-sakai/ParticleEffectForUGUI/issues/316)
+* the ParticleSystem's localPosition drifts at certain scales due to floating-point precision issues ([a9c2b19](https://github.com/mob-sakai/ParticleEffectForUGUI/commit/a9c2b19edf00e1c86c928ef23405906952ede852)), closes [#299](https://github.com/mob-sakai/ParticleEffectForUGUI/issues/299) [#312](https://github.com/mob-sakai/ParticleEffectForUGUI/issues/312)
+* UIParticle is scaled by canvas size even when `AutoScalingMode.None` and `ScalingMode.Local` ([63b24d8](https://github.com/mob-sakai/ParticleEffectForUGUI/commit/63b24d8a8b478b3165733ece3eec524e88b28855)), closes [#313](https://github.com/mob-sakai/ParticleEffectForUGUI/issues/313)
+* UIParticle is scaled incorrectly with nested canvases ([c95d8c6](https://github.com/mob-sakai/ParticleEffectForUGUI/commit/c95d8c6b1774396ff252d13121ad32a3cab0fe5c)), closes [#313](https://github.com/mob-sakai/ParticleEffectForUGUI/issues/313)
+
+
+### Features
+
+* remove overlay window (editor) ([fc3fbdd](https://github.com/mob-sakai/ParticleEffectForUGUI/commit/fc3fbdd230595ad3471875ec6fec384a3dad0d17))
+* reset previous position on start play for world space simulation ([e741584](https://github.com/mob-sakai/ParticleEffectForUGUI/commit/e7415845074143abae23e3ae7eedc767a01d020d)), closes [#303](https://github.com/mob-sakai/ParticleEffectForUGUI/issues/303)
+* restore `Transform.localScale` when setting `autoScalingMode` to something other than `Transform` ([dfb94f4](https://github.com/mob-sakai/ParticleEffectForUGUI/commit/dfb94f4badfb3035a4374579c53293460b4fd946))
+
 # [5.0.0-preview.1](https://github.com/mob-sakai/ParticleEffectForUGUI/compare/v4.6.6...v5.0.0-preview.1) (2024-05-23)
 
 

Editor/UIParticleEditor.cs

@@ -28,29 +28,6 @@ namespace Coffee.UIExtensions
     [CanEditMultipleObjects]
     internal class UIParticleEditor : Editor
     {
-#if UNITY_2021_2_OR_NEWER
-#if UNITY_2022_1_OR_NEWER
-        [Overlay(typeof(SceneView), "Scene View/UI Particles", "UI Particles", true,
-            defaultDockPosition = DockPosition.Bottom,
-            defaultDockZone = DockZone.Floating,
-            defaultLayout = Layout.Panel)]
-#else
-        [Overlay(typeof(SceneView), "Scene View/UI Particles", "UI Particles", true)]
-#endif
-        private class UIParticleOverlay : IMGUIOverlay, ITransientOverlay
-        {
-            public bool visible => s_SerializedObject != null;
-
-            public override void OnGUI()
-            {
-                if (visible)
-                {
-                    WindowFunction();
-                }
-            }
-        }
-#endif
-
         //################################
         // Constant or Static Members.
         //################################
@@ -62,7 +39,6 @@ namespace Coffee.UIExtensions
         private static readonly GUIContent s_Content3D = new GUIContent("3D");
         private static readonly GUIContent s_ContentRandom = new GUIContent("Random");
         private static readonly GUIContent s_ContentScale = new GUIContent("Scale");
-        private static SerializedObject s_SerializedObject;
         private static bool s_XYZMode;
 
         private SerializedProperty _maskable;
@@ -90,56 +66,6 @@ namespace Coffee.UIExtensions
             "_ColorMask"
         };
 
-        [InitializeOnLoadMethod]
-        private static void Init()
-        {
-#if !UNITY_2021_2_OR_NEWER
-            var miSceneViewOverlayWindow = Type.GetType("UnityEditor.SceneViewOverlay, UnityEditor")
-                ?.GetMethods(BindingFlags.Public | BindingFlags.Static)
-                .First(x => x.Name == "Window" && 5 <= x.GetParameters().Length);
-            var windowFunction = (Action<Object, SceneView>)WindowFunction;
-            var windowFunctionType = Type.GetType("UnityEditor.SceneViewOverlay+WindowFunction, UnityEditor");
-            var windowFunctionDelegate = Delegate.CreateDelegate(windowFunctionType, windowFunction.Method);
-            var windowTitle = new GUIContent(ObjectNames.NicifyVariableName(nameof(UIParticle)));
-#if UNITY_2019_2_OR_NEWER
-            //public static void Window(GUIContent title, WindowFunction sceneViewFunc, int order, Object target, WindowDisplayOption option, EditorWindow window = null)
-            var sceneViewArgs = new object[] { windowTitle, windowFunctionDelegate, 599, null, 2, null };
-#else
-            //public static void Window(GUIContent title, WindowFunction sceneViewFunc, int order, Object target, WindowDisplayOption option)
-            var sceneViewArgs = new object[] { windowTitle, windowFunctionDelegate, 599, null, 2 };
-#endif
-
-#if UNITY_2019_1_OR_NEWER
-            SceneView.duringSceneGui += _ =>
-#else
-            SceneView.onSceneGUIDelegate += _ =>
-#endif
-            {
-                if (s_SerializedObject != null)
-                {
-                    miSceneViewOverlayWindow.Invoke(null, sceneViewArgs);
-                }
-            };
-#endif
-
-            SerializedObject CreateSerializeObject()
-            {
-                var uiParticles = Selection.gameObjects.Select(x => x.GetComponent<ParticleSystem>())
-                    .Where(x => x)
-                    .Select(x => x.GetComponentInParent<UIParticle>(true))
-                    .Where(x => x && x.canvas)
-                    .Concat(Selection.gameObjects.Select(x => x.GetComponent<UIParticle>())
-                        .Where(x => x && x.canvas))
-                    .Distinct()
-                    .OfType<Object>()
-                    .ToArray();
-                return 0 < uiParticles.Length ? new SerializedObject(uiParticles) : null;
-            }
-
-            s_SerializedObject = CreateSerializeObject();
-            Selection.selectionChanged += () => s_SerializedObject = CreateSerializeObject();
-        }
-
         //################################
         // Public/Protected Members.
         //################################
@@ -475,52 +401,7 @@ namespace Coffee.UIExtensions
 
         private static void DrawAutoScaling(SerializedProperty prop, IEnumerable<UIParticle> uiParticles)
         {
-            var isTransformMode = prop.intValue == (int)UIParticle.AutoScalingMode.Transform;
-            EditorGUI.BeginChangeCheck();
             EditorGUILayout.PropertyField(prop);
-            if (!EditorGUI.EndChangeCheck() || !isTransformMode) return;
-
-            // on changed true->false, reset scale.
-            EditorApplication.delayCall += () =>
-            {
-                foreach (var uip in uiParticles)
-                {
-                    if (!uip) continue;
-                    uip.transform.localScale = Vector3.one;
-                }
-            };
-        }
-
-#if UNITY_2021_2_OR_NEWER
-        private static void WindowFunction()
-#else
-        private static void WindowFunction(Object _, SceneView __)
-#endif
-        {
-            try
-            {
-                if (s_SerializedObject == null || !s_SerializedObject.targetObject) return;
-                var uiParticles = s_SerializedObject.targetObjects.OfType<UIParticle>().ToArray();
-                if (uiParticles.Any(x => !x || !x.canvas)) return;
-
-                s_SerializedObject.Update();
-                using (new EditorGUILayout.VerticalScope(GUILayout.Width(220f)))
-                {
-                    var labelWidth = EditorGUIUtility.labelWidth;
-                    EditorGUIUtility.labelWidth = 100;
-                    EditorGUILayout.PropertyField(s_SerializedObject.FindProperty("m_Enabled"));
-                    s_XYZMode = DrawFloatOrVector3Field(s_SerializedObject.FindProperty("m_Scale3D"), s_XYZMode);
-                    EditorGUILayout.PropertyField(s_SerializedObject.FindProperty("m_PositionMode"));
-                    DrawAutoScaling(s_SerializedObject.FindProperty("m_AutoScalingMode"), uiParticles);
-                    EditorGUIUtility.labelWidth = labelWidth;
-                }
-
-                s_SerializedObject.ApplyModifiedProperties();
-            }
-            catch
-            {
-                // ignored
-            }
         }
 
         private void DestroyUIParticle(UIParticle p, bool ignoreCurrent = false)

LICENSE.md

@@ -1,4 +1,4 @@
-Copyright 2018-2023 mob-sakai
+Copyright 2018-2024 mob-sakai
 
 Permission is hereby granted, free of charge, to any person obtaining a copy of this software and associated documentation files (the "Software"), to deal in the Software without restriction, including without limitation the rights to use, copy, modify, merge, publish, distribute, sublicense, and/or sell copies of the Software, and to permit persons to whom the Software is furnished to do so, subject to the following conditions:
 

Runtime/Internal/Extensions/ComponentExtensions.cs

@@ -1,4 +1,5 @@
 using System;
+using System.Collections.Generic;
 using UnityEditor;
 using UnityEngine;
 using UnityEngine.Profiling;
@@ -11,6 +12,48 @@ namespace Coffee.UIParticleInternal
     /// </summary>
     internal static class ComponentExtensions
     {
+        /// <summary>
+        /// Get components in children of a specific type in the hierarchy of a GameObject.
+        /// </summary>
+        public static T[] GetComponentsInChildren<T>(this Component self, int depth)
+            where T : Component
+        {
+            var results = ListPool<T>.Rent();
+            self.GetComponentsInChildren_Internal(results, depth);
+            var array = results.ToArray();
+            ListPool<T>.Return(ref results);
+            return array;
+        }
+
+        /// <summary>
+        /// Get components in children of a specific type in the hierarchy of a GameObject.
+        /// </summary>
+        public static void GetComponentsInChildren<T>(this Component self, List<T> results, int depth)
+            where T : Component
+        {
+            results.Clear();
+            self.GetComponentsInChildren_Internal(results, depth);
+        }
+
+        private static void GetComponentsInChildren_Internal<T>(this Component self, List<T> results, int depth)
+            where T : Component
+        {
+            if (!self || results == null || depth < 0) return;
+
+            var tr = self.transform;
+            if (tr.TryGetComponent<T>(out var t))
+            {
+                results.Add(t);
+            }
+
+            if (depth - 1 < 0) return;
+            var childCount = tr.childCount;
+            for (var i = 0; i < childCount; i++)
+            {
+                tr.GetChild(i).GetComponentsInChildren(results, depth - 1);
+            }
+        }
+
         /// <summary>
         /// Get or add a component of a specific type to a GameObject.
         /// </summary>

Runtime/Internal/Utilities/Logging.cs

@@ -1,11 +1,13 @@
 using System;
 using System.Text;
 using UnityEngine;
-using Conditional = System.Diagnostics.ConditionalAttribute;
 using Object = UnityEngine.Object;
 #if ENABLE_COFFEE_LOGGER
 using System.Reflection;
 using System.Collections.Generic;
+
+#else
+using Conditional = System.Diagnostics.ConditionalAttribute;
 #endif
 
 namespace Coffee.UIParticleInternal

Runtime/Internal/Utilities/MaterialRepository.cs

@@ -42,6 +42,34 @@ namespace Coffee.UIParticleInternal
             Profiler.EndSample();
         }
 
+        /// <summary>
+        /// Adds or retrieves a cached material based on the hash.
+        /// </summary>
+        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))
+            {
+                hideFlags = HideFlags.DontSave | HideFlags.NotEditable
+            }, shaderName);
+            Profiler.EndSample();
+        }
+
+
+        /// <summary>
+        /// Adds or retrieves a cached material based on the hash.
+        /// </summary>
+        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))
+            {
+                hideFlags = HideFlags.DontSave | HideFlags.NotEditable,
+                shaderKeywords = x.keywords
+            }, (shaderName, keywords));
+            Profiler.EndSample();
+        }
+
         /// <summary>
         /// Adds or retrieves a cached material based on the hash.
         /// </summary>

Runtime/UIParticle.cs

@@ -109,8 +109,10 @@ namespace Coffee.UIExtensions
         private readonly List<UIParticleRenderer> _renderers = new List<UIParticleRenderer>();
         private Canvas _canvas;
         private int _groupId;
-        private Camera _orthographicCamera;
+        private Camera _bakeCamera;
         private DrivenRectTransformTracker _tracker;
+        private Vector3 _storedScale;
+        private bool _isScaleStored;
 
         public RectTransform rectTransform => transform as RectTransform;
 
@@ -232,7 +234,12 @@ namespace Coffee.UIExtensions
             {
                 if (m_AutoScalingMode == value) return;
                 m_AutoScalingMode = value;
-                UpdateTracker();
+
+                if (autoScalingMode != AutoScalingMode.Transform && _isScaleStored)
+                {
+                    transform.localScale = _storedScale;
+                    _isScaleStored = false;
+                }
             }
         }
 
@@ -275,9 +282,9 @@ namespace Coffee.UIExtensions
         /// <summary>
         /// Particle effect scale.
         /// </summary>
-        public Vector3 scale3DForCalc => autoScalingMode == AutoScalingMode.UIParticle
+        public Vector3 scale3DForCalc => autoScalingMode == AutoScalingMode.Transform
-            ? m_Scale3D.GetScaled(canvasScale)
+            ? m_Scale3D
-            : m_Scale3D;
+            : m_Scale3D.GetScaled(canvasScale, transform.localScale);
 
         public List<ParticleSystem> particles => m_Particles;
 
@@ -308,8 +315,8 @@ namespace Coffee.UIExtensions
 
         protected override void OnEnable()
         {
+            _isScaleStored = false;
             ResetGroupId();
-            UpdateTracker();
             UIParticleUpdater.Register(this);
 
             //
@@ -330,7 +337,13 @@ namespace Coffee.UIExtensions
         /// </summary>
         protected override void OnDisable()
         {
-            UpdateTracker();
+            _tracker.Clear();
+            if (autoScalingMode == AutoScalingMode.Transform && _isScaleStored)
+            {
+                transform.localScale = _storedScale;
+            }
+
+            _isScaleStored = false;
             UIParticleUpdater.Unregister(this);
             _renderers.ForEach(r => r.Reset());
             _canvas = null;
@@ -359,15 +372,6 @@ namespace Coffee.UIExtensions
             _canvas = null;
         }
 
-#if UNITY_EDITOR
-        protected override void OnValidate()
-        {
-            base.OnValidate();
-            UpdateTracker();
-            UpdateRendererMaterial();
-        }
-#endif
-
         void ISerializationCallbackReceiver.OnBeforeSerialize()
         {
         }
@@ -583,12 +587,26 @@ namespace Coffee.UIExtensions
 
         internal void UpdateTransformScale()
         {
+            _tracker.Clear();
             canvasScale = canvas.rootCanvas.transform.localScale.Inverse();
             parentScale = transform.parent.lossyScale;
-            if (autoScalingMode != AutoScalingMode.Transform) return;
+            if (autoScalingMode != AutoScalingMode.Transform)
+            {
+                if (_isScaleStored)
+                {
+                    transform.localScale = _storedScale;
+                }
 
+                _isScaleStored = false;
+                return;
+            }
+
+            var currentScale = transform.localScale;
+            _storedScale = currentScale;
+            _isScaleStored = true;
+            _tracker.Add(this, rectTransform, DrivenTransformProperties.Scale);
             var newScale = parentScale.Inverse();
-            if (transform.localScale != newScale)
+            if (currentScale != newScale)
             {
                 transform.localScale = newScale;
             }
@@ -653,64 +671,47 @@ namespace Coffee.UIExtensions
         private Camera GetBakeCamera()
         {
             if (!canvas) return Camera.main;
+            if (_bakeCamera) return _bakeCamera;
 
-            // When render mode is ScreenSpaceCamera or WorldSpace, use world camera.
+            // Find existing baking camera.
-            var root = canvas.rootCanvas;
+            var childCount = transform.childCount;
-            if (root.renderMode != RenderMode.ScreenSpaceOverlay)
+            for (var i = 0; i < childCount; i++)
             {
-                return root.worldCamera ? root.worldCamera : Camera.main;
+                if (transform.GetChild(i).TryGetComponent<Camera>(out var cam)
-            }
+                    && cam.name == "[generated] UIParticle BakingCamera")
-
-            // When render mode is ScreenSpaceOverlay, use orthographic-camera.
-            if (!_orthographicCamera)
-            {
-                // Find existing orthographic-camera.
-                var childCount = transform.childCount;
-                for (var i = 0; i < childCount; i++)
                 {
-                    if (transform.GetChild(i).TryGetComponent<Camera>(out var cam)
+                    _bakeCamera = cam;
-                        && cam.name == "[generated] UIParticleOverlayCamera")
+                    break;
-                    {
-                        _orthographicCamera = cam;
-                        break;
-                    }
-                }
-
-                // Create orthographic-camera.
-                if (!_orthographicCamera)
-                {
-                    var go = new GameObject("[generated] UIParticleOverlayCamera")
-                    {
-                        hideFlags = HideFlags.HideAndDontSave
-                    };
-                    go.SetActive(false);
-                    go.transform.SetParent(transform, false);
-                    _orthographicCamera = go.AddComponent<Camera>();
-                    _orthographicCamera.enabled = false;
                 }
             }
 
-            //
+            // Create baking camera.
-            _orthographicCamera.orthographicSize = 10;
+            if (!_bakeCamera)
-            _orthographicCamera.transform.SetPositionAndRotation(new Vector3(0, 0, -1000), Quaternion.identity);
-            _orthographicCamera.orthographic = true;
-            _orthographicCamera.farClipPlane = 2000f;
-
-            return _orthographicCamera;
-        }
-
-        private void UpdateTracker()
-        {
-#pragma warning disable CS0618 // Type or member is obsolete
-            if (!enabled || autoScalingMode != AutoScalingMode.Transform)
-#pragma warning restore CS0618 // Type or member is obsolete
             {
-                _tracker.Clear();
+                var go = new GameObject("[generated] UIParticle BakingCamera")
-            }
+                {
-            else
+                    // hideFlags = HideFlags.HideAndDontSave
-            {
+                    hideFlags = HideFlags.DontSave
-                _tracker.Add(this, rectTransform, DrivenTransformProperties.Scale);
+                };
+                go.SetActive(false);
+                go.transform.SetParent(transform, false);
+                _bakeCamera = go.AddComponent<Camera>();
             }
+
+            // Setup baking camera.
+            _bakeCamera.enabled = false;
+            _bakeCamera.orthographicSize = 1000;
+            _bakeCamera.transform.SetPositionAndRotation(new Vector3(0, 0, -1000), Quaternion.identity);
+            _bakeCamera.orthographic = true;
+            _bakeCamera.farClipPlane = 2000f;
+            _bakeCamera.clearFlags = CameraClearFlags.Nothing;
+            _bakeCamera.cullingMask = 0; // Nothing
+            _bakeCamera.allowHDR = false;
+            _bakeCamera.allowMSAA = false;
+            _bakeCamera.renderingPath = RenderingPath.Forward;
+            _bakeCamera.useOcclusionCulling = false;
+
+            return _bakeCamera;
         }
     }
 }

Runtime/UIParticleRenderer.cs

@@ -38,6 +38,7 @@ namespace Coffee.UIExtensions
         private float _prevCanvasScale;
         private Vector3 _prevPsPos;
         private Vector3 _prevScale;
+        private bool _isPrevStored;
         private Vector2Int _prevScreenSize;
         private bool _preWarm;
         private ParticleSystemRenderer _renderer;
@@ -153,6 +154,7 @@ namespace Coffee.UIExtensions
 
             MaterialRepository.Release(ref _modifiedMaterial);
             _materialForRendering = null;
+            _isPrevStored = false;
         }
 
         public static UIParticleRenderer AddRenderer(UIParticle parent, int index)
@@ -508,7 +510,7 @@ namespace Coffee.UIExtensions
                 && _particleSystem.main.scalingMode == ParticleSystemScalingMode.Local
                 && _parent.canvas)
             {
-                scale = scale.GetScaled(_parent.canvas.transform.localScale);
+                scale = scale.GetScaled(_parent.canvas.rootCanvas.transform.localScale);
             }
 
             Profiler.EndSample();
@@ -563,7 +565,7 @@ namespace Coffee.UIExtensions
             var canvasScale = _parent.canvas ? _parent.canvas.scaleFactor : 1f;
             var resolutionChanged = _prevScreenSize != screenSize
                                     || !Mathf.Approximately(_prevCanvasScale, canvasScale);
-            if (resolutionChanged && isWorldSpace)
+            if (resolutionChanged && isWorldSpace && _isPrevStored)
             {
                 // Update particle array size and get particles.
                 var size = _particleSystem.particleCount;
@@ -589,6 +591,7 @@ namespace Coffee.UIExtensions
                 _delay = true;
                 _prevScale = scale;
                 _prevPsPos = psPos;
+                _isPrevStored = true;
             }
 
             _prevCanvasScale = canvas ? canvas.scaleFactor : 1f;
@@ -614,13 +617,15 @@ namespace Coffee.UIExtensions
             // get world position.
             var isLocalSpace = _particleSystem.IsLocalSpace();
             var psTransform = _particleSystem.transform;
+            var originLocalPosition = psTransform.localPosition;
+            var originLocalRotation = psTransform.localRotation;
             var originWorldPosition = psTransform.position;
             var originWorldRotation = psTransform.rotation;
             var emission = _particleSystem.emission;
             var rateOverDistance = emission.enabled
                                    && 0 < emission.rateOverDistance.constant
                                    && 0 < emission.rateOverDistanceMultiplier;
-            if (rateOverDistance && !paused)
+            if (rateOverDistance && !paused && _isPrevStored)
             {
                 // (For rate-over-distance emission,) Move to previous scaled position, simulate (delta = 0).
                 var prevScaledPos = isLocalSpace
@@ -636,7 +641,8 @@ namespace Coffee.UIExtensions
                 : originWorldPosition.GetScaled(scale.Inverse());
             psTransform.SetPositionAndRotation(scaledPos, originWorldRotation);
             _particleSystem.Simulate(deltaTime, false, false, false);
-            psTransform.SetPositionAndRotation(originWorldPosition, originWorldRotation);
+            psTransform.localPosition = originLocalPosition;
+            psTransform.localRotation = originLocalRotation;
         }
 
 #if UNITY_EDITOR

Runtime/UIParticleUpdater.cs

@@ -58,9 +58,8 @@ namespace Coffee.UIExtensions
             for (var i = 0; i < s_ActiveParticles.Count; i++)
             {
                 var uip = s_ActiveParticles[i];
-                if (!uip || !uip.canvas || !uip.isPrimary || s_UpdatedGroupIds.Contains(uip.groupId)) continue;
+                if (!uip || !uip.canvas || !uip.isPrimary || !s_UpdatedGroupIds.Add(uip.groupId)) continue;
 
-                s_UpdatedGroupIds.Add(uip.groupId);
                 uip.UpdateTransformScale();
                 uip.UpdateRenderers();
             }
@@ -77,9 +76,8 @@ namespace Coffee.UIExtensions
                 {
                     uip.UpdateRenderers();
                 }
-                else if (!s_UpdatedGroupIds.Contains(uip.groupId))
+                else if (s_UpdatedGroupIds.Add(uip.groupId))
                 {
-                    s_UpdatedGroupIds.Add(uip.groupId);
                     uip.UpdateRenderers();
                 }
             }

Samples~/Demo/UIParticle_Demo.unity

@@ -14461,7 +14461,7 @@ Canvas:
   m_GameObject: {fileID: 1074082869}
   m_Enabled: 1
   serializedVersion: 3
-  m_RenderMode: 0
+  m_RenderMode: 1
   m_Camera: {fileID: 1023393581}
   m_PlaneDistance: 100
   m_PixelPerfect: 0

package.json

@@ -2,7 +2,7 @@
   "name": "com.coffee.ui-particle",
   "displayName": "UI Particle",
   "description": "This package provides a component to render particle effects for uGUI.\nThe particle rendering is maskable and sortable, without the need for an extra Camera, RenderTexture, or Canvas.",
-  "version": "5.0.0-preview.1",
+  "version": "5.0.0-preview.2",
   "unity": "2018.2",
   "license": "MIT",
   "repository": {