feat: random mesh sharing group

The mesh sharing group id will be selected randomly.

Scripts/Editor/UIParticleEditor.cs

@@ -50,6 +50,7 @@ namespace Coffee.UIExtensions
         private static readonly GUIContent s_ContentMaterial = new GUIContent("Material");
         private static readonly GUIContent s_ContentTrailMaterial = new GUIContent("Trail Material");
         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;
 
@@ -60,9 +61,12 @@ namespace Coffee.UIExtensions
         private SerializedProperty m_AnimatableProperties;
         private SerializedProperty m_MeshSharing;
         private SerializedProperty m_GroupId;
+        private SerializedProperty m_GroupMaxId;
+
 
         private ReorderableList _ro;
         static private bool _xyzMode;
+        private bool _showMax;
 
         private static readonly List<string> s_MaskablePropertyNames = new List<string>
         {
@@ -137,6 +141,7 @@ namespace Coffee.UIExtensions
             m_AnimatableProperties = serializedObject.FindProperty("m_AnimatableProperties");
             m_MeshSharing = serializedObject.FindProperty("m_MeshSharing");
             m_GroupId = serializedObject.FindProperty("m_GroupId");
+            m_GroupMaxId = serializedObject.FindProperty("m_GroupMaxId");
 
             var sp = serializedObject.FindProperty("m_Particles");
             _ro = new ReorderableList(sp.serializedObject, sp, true, true, true, true);
@@ -232,7 +237,16 @@ namespace Coffee.UIExtensions
             AnimatedPropertiesEditor.DrawAnimatableProperties(m_AnimatableProperties, mats);
 
             // Mesh sharing
-            DrawMeshSharing();
+            EditorGUI.BeginChangeCheck();
+            _showMax = DrawMeshSharing(m_MeshSharing, m_GroupId, m_GroupMaxId, _showMax);
+            if (EditorGUI.EndChangeCheck())
+            {
+                serializedObject.ApplyModifiedProperties();
+                foreach (var uip in targets.OfType<UIParticle>())
+                {
+                    uip.ResetGroupId();
+                }
+            }
 
             // Target ParticleSystems.
             _ro.DoLayoutList();
@@ -281,20 +295,38 @@ namespace Coffee.UIExtensions
             }
         }
 
-        private void DrawMeshSharing()
+        private static bool DrawMeshSharing(SerializedProperty spMeshSharing, SerializedProperty spGroupId, SerializedProperty spGroupMaxId, bool showMax)
         {
-            EditorGUILayout.PropertyField(m_MeshSharing);
+            showMax |= spGroupId.intValue != spGroupMaxId.intValue ||
-            EditorGUI.BeginDisabledGroup(m_MeshSharing.intValue == 0);
+                       spGroupId.hasMultipleDifferentValues ||
+                       spGroupMaxId.hasMultipleDifferentValues;
+
+            EditorGUILayout.BeginHorizontal();
+            EditorGUILayout.PropertyField(spMeshSharing);
+
+            EditorGUI.BeginChangeCheck();
+            showMax = GUILayout.Toggle(showMax, s_ContentRandom, EditorStyles.miniButton, GUILayout.Width(60));
+            if (EditorGUI.EndChangeCheck() && !showMax)
+                spGroupMaxId.intValue = spGroupId.intValue;
+            EditorGUILayout.EndHorizontal();
+
+            EditorGUI.BeginDisabledGroup(spMeshSharing.intValue == 0);
             EditorGUI.indentLevel++;
-            EditorGUILayout.PropertyField(m_GroupId);
+            EditorGUILayout.PropertyField(spGroupId);
-            if (m_MeshSharing.intValue == 1 || m_MeshSharing.intValue == 4)
+            if (showMax)
+            {
+                EditorGUILayout.PropertyField(spGroupMaxId);
+            }
+            else if (spMeshSharing.intValue == 1 || spMeshSharing.intValue == 4)
             {
                 EditorGUI.BeginDisabledGroup(true);
-                EditorGUILayout.ObjectField("Primary", UIParticleUpdater.GetPrimary(m_GroupId.intValue), typeof(UIParticle), false);
+                EditorGUILayout.ObjectField("Primary", UIParticleUpdater.GetPrimary(spGroupId.intValue), typeof(UIParticle), false);
                 EditorGUI.EndDisabledGroup();
             }
             EditorGUI.indentLevel--;
             EditorGUI.EndDisabledGroup();
+
+            return showMax;
         }
 
         private static void WindowFunction(UnityEngine.Object target, SceneView sceneView)

Scripts/UIParticle.cs

@@ -51,6 +51,9 @@ namespace Coffee.UIExtensions
         [SerializeField]
         private int m_GroupId = 0;
 
+        [SerializeField]
+        private int m_GroupMaxId = 0;
+
         private List<UIParticleRenderer> m_Renderers = new List<UIParticleRenderer>();
 
 #if !SERIALIZE_FIELD_MASKABLE
@@ -59,6 +62,7 @@ namespace Coffee.UIExtensions
 
         private DrivenRectTransformTracker _tracker;
         private Camera _orthoCamera;
+        private int _groupId;
 
         /// <summary>
         /// Should this graphic be considered a target for raycasting?
@@ -87,8 +91,25 @@ namespace Coffee.UIExtensions
         /// </summary>
         public int groupId
         {
-            get { return m_GroupId; }
+            get { return _groupId; }
-            set { m_GroupId = value; }
+            set
+            {
+                if (m_GroupId == value) return;
+                m_GroupId = value;
+                if (m_GroupId != m_GroupMaxId)
+                    ResetGroupId();
+            }
+        }
+
+        public int groupMaxId
+        {
+            get { return m_GroupMaxId; }
+            set
+            {
+                if (m_GroupMaxId == value) return;
+                m_GroupMaxId = value;
+                ResetGroupId();
+            }
         }
 
         internal bool useMeshSharing
@@ -295,6 +316,7 @@ namespace Coffee.UIExtensions
 #if !SERIALIZE_FIELD_MASKABLE
             maskable = m_Maskable;
 #endif
+            ResetGroupId();
             _tracker.Add(this, rectTransform, DrivenTransformProperties.Scale);
             UIParticleUpdater.Register(this);
             RegisterDirtyMaterialCallback(UpdateRendererMaterial);
@@ -303,6 +325,18 @@ namespace Coffee.UIExtensions
             base.OnEnable();
         }
 
+        internal void ResetGroupId()
+        {
+            if (m_GroupId == m_GroupMaxId)
+            {
+                _groupId = m_GroupId;
+            }
+            else
+            {
+                _groupId = Random.Range(m_GroupId, m_GroupMaxId + 1);
+            }
+        }
+
         /// <summary>
         /// This function is called when the behaviour becomes disabled.
         /// </summary>