Various refactorings and improvements (#139)

* Move previewMode to RenderData instead of ShaderData (still some to do here, as apparently there's still a RenderData _and a_ ShaderData per node, but the intention was to have a RenderData per node and then share ShaderData between those)
* Introduce a temporary identifier for nodes. The first part of this identifier is an index (`int`) which is assigned linearly. When a node is deleted, its identifier as added to a free list. Each identifier also contains a version (`int`), which is incremented when the identifier is re-used. This allows us to replace usage of Dictionary with List in a lot of places.
* Introduce IndexSet for efficiently storing and manipulating a list of indices (e.g. from temp IDs). Internally this stores a list of 32-bit integers and uses each bit to represent 1 index. The operations of `ISet<int>` are implemented for this type, although that interface does not exist in Unity. The operations are very fast and cac...

MaterialGraphProject/Assets/NewNodes/Editor/FunctionNAddNode.cs

 
           public void OnModified()
           {
-              if (onModified != null)
-                  onModified(this, ModificationScope.Node);
+              Dirty(ModificationScope.Node);
           }
 
           protected override string GetFunctionName()

MaterialGraphProject/Assets/NewNodes/Editor/Keep/ConvolutionFilterNode.cs

 
             m_ConvolutionFilter[6].w = value;
 
-            if (onModified != null)
-                onModified(this, ModificationScope.Node);
+            Dirty(ModificationScope.Node);
         }
 
         public float GetConvolutionWeight(int row, int col)
                 default: m_ConvolutionFilter[vectorIndex].w = value; break;
             }
 
-            if (onModified != null)
-                onModified(this, ModificationScope.Node);
+            Dirty(ModificationScope.Node);
         }
 
         protected override string GetFunctionName()

MaterialGraphProject/Assets/NewNodes/Editor/Kill/ScatterNode.cs

                   }
 
                   m_num = value;
-                  if (onModified != null)
-                  {
-                      onModified(this, ModificationScope.Graph);
-                  }
+                  Dirty(ModificationScope.Graph);
               }
           }
 

MaterialGraphProject/Assets/NewNodes/Editor/Kill/ToggleNode.cs

                      return;
 
                  m_ToggleState = value;
-                 if (onModified != null)
-                 {
-                     onModified(this, ModificationScope.Node);
-                 }
+                 Dirty(ModificationScope.Node);
              }
          }
 

MaterialGraphProject/Assets/NewNodes/Editor/Kill/UVTransform.cs

                     return;
 
                 m_constant = value;
-                if (onModified != null)
-                {
-                    onModified(this, ModificationScope.Graph);
-                }
+                Dirty(ModificationScope.Graph);
             }
         }
         public UVTransform()

MaterialGraphProject/Assets/NewNodes/Editor/SceneDepthNode.cs

                     return;
 
                 m_SceneDepthMode = value;
-                if (onModified != null)
-                {
-                    onModified(this, ModificationScope.Graph);
-                }
+                Dirty(ModificationScope.Graph);
             }
         }
 

MaterialGraphProject/Assets/NewNodes/Editor/SceneVelocityNode.cs

                     return;
 
                 m_SceneVelocityMode = value;
-                if (onModified != null)
-                {
-                    onModified(this, ModificationScope.Graph);
-                }
+                Dirty(ModificationScope.Graph);
             }
         }
 

MaterialGraphProject/Assets/UnityShaderEditor/Editor/Data/Graphs/AbstractMaterialGraph.cs

         #region Node data
 
         [NonSerialized]
-        Dictionary<Guid, INode> m_Nodes = new Dictionary<Guid, INode>();
+        Stack<Identifier> m_FreeNodeTempIds = new Stack<Identifier>();
+
+        [NonSerialized]
+        List<AbstractMaterialNode> m_Nodes = new List<AbstractMaterialNode>();
+
+        [NonSerialized]
+        Dictionary<Guid, INode> m_NodeDictionary = new Dictionary<Guid, INode>();
-            return m_Nodes.Values.OfType<T>();
+            return m_Nodes.Where(x => x != null).OfType<T>();
         }
 
         [SerializeField]
 
         void AddNodeNoValidate(INode node)
         {
-            m_Nodes.Add(node.guid, node);
-            node.owner = this;
-            m_AddedNodes.Add(node);
+            var materialNode = (AbstractMaterialNode)node;
+            materialNode.owner = this;
+            if (m_FreeNodeTempIds.Any())
+            {
+                var id = m_FreeNodeTempIds.Pop();
+                id.IncrementVersion();
+                materialNode.tempId = id;
+                m_Nodes[id.index] = materialNode;
+            }
+            else
+            {
+                var id = new Identifier(m_Nodes.Count);
+                materialNode.tempId = id;
+                m_Nodes.Add(materialNode);
+            }
+            m_NodeDictionary.Add(materialNode.guid, materialNode);
+            m_AddedNodes.Add(materialNode);
         }
 
         public void RemoveNode(INode node)
-
-            m_Nodes.Remove(node.guid);
-            m_RemovedNodes.Add(node);
-            if (!node.canDeleteNode)
+            var materialNode = (AbstractMaterialNode)node;
+            if (!materialNode.canDeleteNode)
-            m_Nodes.Remove(node.guid);
-            m_RemovedNodes.Add(node);
+            m_Nodes[materialNode.tempId.index] = null;
+            m_FreeNodeTempIds.Push(materialNode.tempId);
+            m_NodeDictionary.Remove(materialNode.guid);
+            m_RemovedNodes.Add(materialNode);
         }
 
         void AddEdgeToNodeEdges(IEdge edge)
         public INode GetNodeFromGuid(Guid guid)
         {
             INode node;
-            m_Nodes.TryGetValue(guid, out node);
+            m_NodeDictionary.TryGetValue(guid, out node);
+            return node;
+        }
+
+        public INode GetNodeFromTempId(Identifier tempId)
+        {
+            var node = m_Nodes[tempId.index];
+            if (node == null)
+                throw new Exception("Index does not contain a node.");
+            if (node.tempId.version != tempId.version)
+                throw new Exception("Trying to retrieve a node that was removed from the graph.");
-            return m_Nodes.ContainsKey(guid);
+            return m_NodeDictionary.ContainsKey(guid);
         }
 
         public T GetNodeFromGuid<T>(Guid guid) where T : INode
             using (var removedNodesPooledObject = ListPool<Guid>.GetDisposable())
             {
                 var removedNodeGuids = removedNodesPooledObject.value;
-                removedNodeGuids.AddRange(m_Nodes.Keys);
+                removedNodeGuids.AddRange(m_Nodes.Where(n => n != null).Select(n => n.guid));
-                    RemoveNodeNoValidate(m_Nodes[nodeGuid]);
+                    RemoveNodeNoValidate(m_NodeDictionary[nodeGuid]);
             }
 
             ValidateGraph();
 
         public void OnBeforeSerialize()
         {
-            m_SerializableNodes = SerializationHelper.Serialize<INode>(m_Nodes.Values);
+            m_SerializableNodes = SerializationHelper.Serialize(GetNodes<INode>());
             m_SerializableEdges = SerializationHelper.Serialize<IEdge>(m_Edges);
             m_SerializedProperties = SerializationHelper.Serialize<IShaderProperty>(m_Properties);
         }
             // have to deserialize 'globals' before nodes
             m_Properties = SerializationHelper.Deserialize<IShaderProperty>(m_SerializedProperties, null);
             var nodes = SerializationHelper.Deserialize<INode>(m_SerializableNodes, GraphUtil.GetLegacyTypeRemapping());
-            m_Nodes = new Dictionary<Guid, INode>(nodes.Count);
-            foreach (var node in nodes)
+            m_Nodes = new List<AbstractMaterialNode>(nodes.Count);
+            m_NodeDictionary = new Dictionary<Guid, INode>(nodes.Count);
+            foreach (var node in nodes.OfType<AbstractMaterialNode>())
-                m_Nodes.Add(node.guid, node);
+                node.tempId = new Identifier(m_Nodes.Count);
+                m_Nodes.Add(node);
+                m_NodeDictionary.Add(node.guid, node);
             }
 
             m_SerializableNodes = null;

MaterialGraphProject/Assets/UnityShaderEditor/Editor/Data/Graphs/ColorMaterialSlot.cs

 
         public override PreviewProperty GetPreviewProperty(string name)
         {
-            var pp = new PreviewProperty
+            var pp = new PreviewProperty(PropertyType.Color)
-                propType = PropertyType.Color,
-                vector4Value = new Vector4(value.x, value.y, value.z, value.w),
-                floatValue = value.x,
-                colorValue = new Vector4(value.x, value.x, value.z, value.w),
+                colorValue = new Color(value.x, value.x, value.z, value.w),
             };
             return pp;
         }

MaterialGraphProject/Assets/UnityShaderEditor/Editor/Data/Graphs/ColorRGBMaterialSlot.cs

 
         public override PreviewProperty GetPreviewProperty(string name)
         {
-            var pp = new PreviewProperty
+            var pp = new PreviewProperty(PropertyType.Color)
-                propType = PropertyType.Color,
-                vector4Value = new Vector4(value.x, value.y, value.z, 1),
-                floatValue = value.x,
-                colorValue = new Vector4(value.x, value.y, value.z, 1),
+                colorValue = new Color(value.x, value.y, value.z, 1),
             };
             return pp;
         }

MaterialGraphProject/Assets/UnityShaderEditor/Editor/Data/Graphs/ColorShaderProperty.cs

 
         public override PreviewProperty GetPreviewMaterialProperty()
         {
-            return new PreviewProperty
+            return new PreviewProperty(PropertyType.Color)
-                propType = PropertyType.Color,
                 colorValue = value
             };
         }

MaterialGraphProject/Assets/UnityShaderEditor/Editor/Data/Graphs/CubemapInputMaterialSlot.cs

 
         public override PreviewProperty GetPreviewProperty(string name)
         {
-            var pp = new PreviewProperty
+            var pp = new PreviewProperty(PropertyType.Cubemap)
-                propType = PropertyType.Cubemap,
                 cubemapValue = cubemap
             };
             return pp;

MaterialGraphProject/Assets/UnityShaderEditor/Editor/Data/Graphs/CubemapShaderProperty.cs

 
         public override PreviewProperty GetPreviewMaterialProperty()
         {
-            return new PreviewProperty()
+            return new PreviewProperty(PropertyType.Cubemap)
-                propType = PropertyType.Cubemap,
                 cubemapValue = value.cubemap
             };
         }

MaterialGraphProject/Assets/UnityShaderEditor/Editor/Data/Graphs/DynamicVectorMaterialSlot.cs

 
         public override PreviewProperty GetPreviewProperty(string name)
         {
-            var pp = new PreviewProperty
-            {
-                name = name,
-                propType = ConvertConcreteSlotValueTypeToPropertyType(concreteValueType),
-                vector4Value = new Vector4(value.x, value.y, value.z, value.w),
-                floatValue = value.x,
-                colorValue = new Vector4(value.x, value.x, value.z, value.w),
-            };
+            var propType = ConvertConcreteSlotValueTypeToPropertyType(concreteValueType);
+            var pp = new PreviewProperty(propType) { name = name };
+            if (propType == PropertyType.Float)
+                pp.floatValue = value.x;
+            else
+                pp.vector4Value = new Vector4(value.x, value.y, value.z, value.w);
             return pp;
         }
 

MaterialGraphProject/Assets/UnityShaderEditor/Editor/Data/Graphs/FloatShaderProperty.cs

 
         public override PreviewProperty GetPreviewMaterialProperty()
         {
-            return new PreviewProperty()
+            return new PreviewProperty(PropertyType.Float)
-                propType = PropertyType.Float,
                 floatValue = value
             };
         }

MaterialGraphProject/Assets/UnityShaderEditor/Editor/Data/Graphs/PreviewProperty.cs

+using System;
+using System.Runtime.InteropServices;
 using UnityEngine;
 
 namespace UnityEditor.ShaderGraph
-        public string name;
-        public PropertyType propType;
+        public string name { get; set; }
+        public PropertyType propType { get; private set; }
+
+        public PreviewProperty(PropertyType type) : this()
+        {
+            propType = type;
+        }
+
+        [StructLayout(LayoutKind.Explicit)]
+        struct Data
+        {
+            [FieldOffset(0)]
+            public Color colorValue;
+            [FieldOffset(0)]
+            public Texture textureValue;
+            [FieldOffset(0)]
+            public Cubemap cubemapValue;
+            [FieldOffset(0)]
+            public Vector4 vector4Value;
+            [FieldOffset(0)]
+            public float floatValue;
+        }
+
+        Data m_Data;
+
+        public Color colorValue
+        {
+            get
+            {
+                if (propType != PropertyType.Color)
+                    throw new ArgumentException(string.Format(k_GetErrorMessage, PropertyType.Color, propType));
+                return m_Data.colorValue;
+            }
+            set
+            {
+                if (propType != PropertyType.Color)
+                    throw new ArgumentException(string.Format(k_SetErrorMessage, PropertyType.Color, propType));
+                m_Data.colorValue = value;
+            }
+        }
+
+        public Texture textureValue
+        {
+            get
+            {
+                if (propType != PropertyType.Texture)
+                    throw new ArgumentException(string.Format(k_GetErrorMessage, PropertyType.Texture, propType));
+                return m_Data.textureValue;
+            }
+            set
+            {
+                if (propType != PropertyType.Texture)
+                    throw new ArgumentException(string.Format(k_SetErrorMessage, PropertyType.Texture, propType));
+                m_Data.textureValue = value;
+            }
+        }
+
+        public Cubemap cubemapValue
+        {
+            get
+            {
+                if (propType != PropertyType.Cubemap)
+                    throw new ArgumentException(string.Format(k_GetErrorMessage, PropertyType.Cubemap, propType));
+                return m_Data.cubemapValue;
+            }
+            set
+            {
+                if (propType != PropertyType.Cubemap)
+                    throw new ArgumentException(string.Format(k_SetErrorMessage, PropertyType.Cubemap, propType));
+                m_Data.cubemapValue = value;
+            }
+        }
-        public Color colorValue;
-        public Texture textureValue;
-        public Cubemap cubemapValue;
-        public Vector4 vector4Value;
-        public float floatValue;
+        public Vector4 vector4Value
+        {
+            get
+            {
+                if (propType != PropertyType.Vector2 && propType != PropertyType.Vector3 && propType != PropertyType.Vector4)
+                    throw new ArgumentException(string.Format(k_GetErrorMessage, PropertyType.Vector4, propType));
+                return m_Data.vector4Value;
+            }
+            set
+            {
+                if (propType != PropertyType.Vector2 && propType != PropertyType.Vector3 && propType != PropertyType.Vector4)
+                    throw new ArgumentException(string.Format(k_SetErrorMessage, PropertyType.Vector4, propType));
+                m_Data.vector4Value = value;
+            }
+        }
+
+        public float floatValue
+        {
+            get
+            {
+                if (propType != PropertyType.Float)
+                    throw new ArgumentException(string.Format(k_GetErrorMessage, PropertyType.Float, propType));
+                return m_Data.floatValue;
+            }
+            set
+            {
+                if (propType != PropertyType.Float)
+                    throw new ArgumentException(string.Format(k_SetErrorMessage, PropertyType.Float, propType));
+                m_Data.floatValue = value;
+            }
+        }
+
+        const string k_SetErrorMessage = "Cannot set a {0} property on a PreviewProperty with type {1}.";
+        const string k_GetErrorMessage = "Cannot get a {0} property on a PreviewProperty with type {1}.";
+
+        public void SetMaterialPropertyBlockValue(MaterialPropertyBlock block)
+        {
+            if (propType == PropertyType.Texture && textureValue != null)
+                block.SetTexture(name, m_Data.textureValue);
+            else if (propType == PropertyType.Cubemap && cubemapValue != null)
+                block.SetTexture(name, m_Data.cubemapValue);
+            else if (propType == PropertyType.Color)
+                block.SetColor(name, m_Data.colorValue);
+            else if (propType == PropertyType.Vector2 || propType == PropertyType.Vector3 || propType == PropertyType.Vector4)
+                block.SetVector(name, m_Data.vector4Value);
+            else if (propType == PropertyType.Float)
+                block.SetFloat(name, m_Data.floatValue);
+        }
+    }
+
+    public static class PreviewPropertyExtensions
+    {
+        public static void SetPreviewProperty(this MaterialPropertyBlock block, PreviewProperty previewProperty)
+        {
+            previewProperty.SetMaterialPropertyBlockValue(block);
+        }
     }
 }

MaterialGraphProject/Assets/UnityShaderEditor/Editor/Data/Graphs/Texture2DInputMaterialSlot.cs

 
         public override PreviewProperty GetPreviewProperty(string name)
         {
-            var pp = new PreviewProperty
+            var pp = new PreviewProperty(PropertyType.Texture)
-                propType = PropertyType.Texture,
                 textureValue = texture
             };
             return pp;

MaterialGraphProject/Assets/UnityShaderEditor/Editor/Data/Graphs/TextureShaderProperty.cs

 
         public override PreviewProperty GetPreviewMaterialProperty()
         {
-            return new PreviewProperty()
+            return new PreviewProperty(PropertyType.Texture)
-                propType = PropertyType.Texture,
                 textureValue = value.texture
             };
         }

MaterialGraphProject/Assets/UnityShaderEditor/Editor/Data/Graphs/Vector1MaterialSlot.cs

 
         public override PreviewProperty GetPreviewProperty(string name)
         {
-            var pp = new PreviewProperty
+            var pp = new PreviewProperty(PropertyType.Float)
-                propType = ConvertConcreteSlotValueTypeToPropertyType(concreteValueType),
-                vector4Value = new Vector4(value, value, value, value),
-                floatValue = value,
-                colorValue = new Vector4(value, value, value, value),
+                floatValue = value
             };
             return pp;
         }

MaterialGraphProject/Assets/UnityShaderEditor/Editor/Data/Graphs/Vector2MaterialSlot.cs

 
         public override PreviewProperty GetPreviewProperty(string name)
         {
-            var pp = new PreviewProperty
+            var pp = new PreviewProperty(PropertyType.Vector2)
-                propType = ConvertConcreteSlotValueTypeToPropertyType(concreteValueType),
-                vector4Value = new Vector4(value.x, value.y, 0, 0),
-                floatValue = value.x,
-                colorValue = new Vector4(value.x, value.x, 0, 0),
+                vector4Value = new Vector4(value.x, value.y, 0, 0)
             };
             return pp;
         }
-
 
         public override void CopyValuesFrom(MaterialSlot foundSlot)
         {

MaterialGraphProject/Assets/UnityShaderEditor/Editor/Data/Graphs/Vector2ShaderProperty.cs

 
         public override PreviewProperty GetPreviewMaterialProperty()
         {
-            return new PreviewProperty()
+            return new PreviewProperty(PropertyType.Vector2)
-                propType = PropertyType.Vector2,
                 vector4Value = value
             };
         }

MaterialGraphProject/Assets/UnityShaderEditor/Editor/Data/Graphs/Vector3MaterialSlot.cs

 
         public override PreviewProperty GetPreviewProperty(string name)
         {
-            var pp = new PreviewProperty
+            var pp = new PreviewProperty(PropertyType.Vector3)
-                propType = ConvertConcreteSlotValueTypeToPropertyType(concreteValueType),
-                vector4Value = new Vector4(value.x, value.y, value.z, 0),
-                floatValue = value.x,
-                colorValue = new Vector4(value.x, value.x, value.z, 0),
+                vector4Value = new Vector4(value.x, value.y, value.z, 0)
             };
             return pp;
         }

MaterialGraphProject/Assets/UnityShaderEditor/Editor/Data/Graphs/Vector3ShaderProperty.cs

 
         public override PreviewProperty GetPreviewMaterialProperty()
         {
-            return new PreviewProperty()
+            return new PreviewProperty(PropertyType.Vector3)
-                propType = PropertyType.Vector3,
                 vector4Value = value
             };
         }

MaterialGraphProject/Assets/UnityShaderEditor/Editor/Data/Graphs/Vector4MaterialSlot.cs

 
         public override PreviewProperty GetPreviewProperty(string name)
         {
-            var pp = new PreviewProperty
+            var pp = new PreviewProperty(PropertyType.Vector4)
-                propType = ConvertConcreteSlotValueTypeToPropertyType(concreteValueType),
-                floatValue = value.x,
-                colorValue = new Vector4(value.x, value.x, value.z, value.w),
             };
             return pp;
         }
-
 
         public override void CopyValuesFrom(MaterialSlot foundSlot)
         {

MaterialGraphProject/Assets/UnityShaderEditor/Editor/Data/Graphs/Vector4ShaderProperty.cs

 
         public override PreviewProperty GetPreviewMaterialProperty()
         {
-            return new PreviewProperty()
+            return new PreviewProperty(PropertyType.Vector4)
-                propType = PropertyType.Vector4,
                 vector4Value = value
             };
         }

MaterialGraphProject/Assets/UnityShaderEditor/Editor/Data/Interfaces/Graph/INode.cs

 using System;
 using System.Collections.Generic;
+using UnityEditor.ShaderGraph;
 
 namespace UnityEditor.Graphing
 {
     public interface INode
     {
         OnNodeModified onModified { get; set; }
+        void Dirty(ModificationScope scope);
+        Identifier tempId { get; set; }
         Guid RewriteGuid();
         string name { get; set; }
         bool canDeleteNode { get; }

MaterialGraphProject/Assets/UnityShaderEditor/Editor/Data/LightweightPipeline/LightWeightPBRSubShader.cs

                 "PopulateSurfaceData",
                 "SurfaceDescription",
                 null,
-                null,
                 usedSlots);
 
             var graph = new ShaderGenerator();

MaterialGraphProject/Assets/UnityShaderEditor/Editor/Data/LightweightPipeline/LightWeightUnlitSubShader.cs

                 "PopulateSurfaceData",
                 "SurfaceDescription",
                 null,
-                null,
                 usedSlots);
 
             var graph = new ShaderGenerator();

MaterialGraphProject/Assets/UnityShaderEditor/Editor/Data/LightweightPipeline/PBRMasterNode.cs

 
                 m_Model = value;
                 UpdateNodeAfterDeserialization();
-                if (onModified != null)
-                {
-                    onModified(this, ModificationScope.Topological);
-                }
+                Dirty(ModificationScope.Topological);
             }
         }
 
                     return;
 
                 m_AlphaMode = value;
-                if (onModified != null)
-                {
-                    onModified(this, ModificationScope.Graph);
-                }
+                Dirty(ModificationScope.Graph);
             }
         }
 

MaterialGraphProject/Assets/UnityShaderEditor/Editor/Data/Nodes/AbstractMaterialNode.cs

 using System;
 using System.Collections.Generic;
 using System.Linq;
-using UnityEditor;
 using UnityEngine;
 using UnityEditor.Graphing;
 
         [NonSerialized]
         private bool m_HasError;
 
+        public Identifier tempId { get; set; }
+
+        public void Dirty(ModificationScope scope)
+        {
+            if (onModified != null)
+                onModified(this, scope);
+        }
+
         public Guid guid
         {
             get { return m_Guid; }
             set
             {
                 m_DrawState = value;
-                if (onModified != null)
-                    onModified(this, ModificationScope.Node);
+                Dirty(ModificationScope.Node);
             }
         }
 
                 if (previewExpanded == value)
                     return;
                 m_PreviewExpanded = value;
-                if (onModified != null)
-                    onModified(this, ModificationScope.Node);
+                Dirty(ModificationScope.Node);
             }
         }
 
             m_Slots.Add(slot);
             slot.owner = this;
 
-            if (onModified != null)
-            {
-                onModified(this, ModificationScope.Topological);
-            }
+            Dirty(ModificationScope.Topological);
 
             if (foundSlot == null)
                 return;
             //remove slots
             m_Slots.RemoveAll(x => x.id == slotId);
 
-            if (onModified != null)
-            {
-                onModified(this, ModificationScope.Topological);
-            }
+            Dirty(ModificationScope.Topological);
         }
 
         public void RemoveSlotsNameNotMatching(IEnumerable<int> slotIds, bool supressWarnings = false)

MaterialGraphProject/Assets/UnityShaderEditor/Editor/Data/Nodes/Artistic/Adjustment/ChannelMixerNode.cs

                 if ((value.outRed == m_ChannelMixer.outRed) && (value.outGreen == m_ChannelMixer.outGreen) && (value.outBlue == m_ChannelMixer.outBlue))
                     return;
                 m_ChannelMixer = value;
-                if (onModified != null)
-                    onModified(this, ModificationScope.Node);
+                Dirty(ModificationScope.Node);
             }
         }
 
         {
             base.CollectPreviewMaterialProperties(properties);
 
-            properties.Add(new PreviewProperty()
+            properties.Add(new PreviewProperty(PropertyType.Vector3)
-                propType = PropertyType.Vector3,
-            properties.Add(new PreviewProperty()
+            properties.Add(new PreviewProperty(PropertyType.Vector3)
-                propType = PropertyType.Vector3,
-            properties.Add(new PreviewProperty()
+            properties.Add(new PreviewProperty(PropertyType.Vector3)
-                propType = PropertyType.Vector3,
                 vector4Value = channelMixer.outBlue
             });
         }

MaterialGraphProject/Assets/UnityShaderEditor/Editor/Data/Nodes/Artistic/Adjustment/HueNode.cs

                     return;
 
                 m_HueMode = value;
-                if (onModified != null)
-                {
-                    onModified(this, ModificationScope.Graph);
-                }
+                Dirty(ModificationScope.Graph);
             }
         }
 

MaterialGraphProject/Assets/UnityShaderEditor/Editor/Data/Nodes/Artistic/Blend/BlendNode.cs

                     return;
 
                 m_BlendMode = value;
-                if (onModified != null)
-                {
-                    onModified(this, ModificationScope.Graph);
-                }
+                Dirty(ModificationScope.Graph);
             }
         }
 

MaterialGraphProject/Assets/UnityShaderEditor/Editor/Data/Nodes/Artistic/Mask/ChannelMaskNode.cs

                     return;
 
                 m_Channel = value;
-                if (onModified != null)
-                {
-                    onModified(this, ModificationScope.Graph);
-                }
+                Dirty(ModificationScope.Graph);
             }
         }
 

MaterialGraphProject/Assets/UnityShaderEditor/Editor/Data/Nodes/Artistic/Utility/ColorspaceConversion.cs

                 if (m_Conversion.Equals(value))
                     return;
                 m_Conversion = value;
-                if (onModified != null)
-                    onModified(this, ModificationScope.Graph);
+                Dirty(ModificationScope.Graph);
             }
         }
 

MaterialGraphProject/Assets/UnityShaderEditor/Editor/Data/Nodes/Channel/FlipNode.cs

                 if (m_RedChannel == value.isOn)
                     return;
                 m_RedChannel = value.isOn;
-                if (onModified != null)
-                {
-                    onModified(this, ModificationScope.Node);
-                }
+                Dirty(ModificationScope.Node);
             }
         }
 
                 if (m_GreenChannel == value.isOn)
                     return;
                 m_GreenChannel = value.isOn;
-                if (onModified != null)
-                {
-                    onModified(this, ModificationScope.Node);
-                }
+                Dirty(ModificationScope.Node);
             }
         }
 
                 if (m_BlueChannel == value.isOn)
                     return;
                 m_BlueChannel = value.isOn;
-                if (onModified != null)
-                {
-                    onModified(this, ModificationScope.Node);
-                }
+                Dirty(ModificationScope.Node);
             }
         }
 
                 if (m_AlphaChannel == value.isOn)
                     return;
                 m_AlphaChannel = value.isOn;
-                if (onModified != null)
-                {
-                    onModified(this, ModificationScope.Node);
-                }
+                Dirty(ModificationScope.Node);
             }
         }
 
         {
             base.CollectPreviewMaterialProperties(properties);
 
-            properties.Add(new PreviewProperty()
+            properties.Add(new PreviewProperty(PropertyType.Vector4)
-                propType = PropertyType.Vector4,
                 vector4Value = new Vector4(Convert.ToInt32(m_RedChannel), Convert.ToInt32(m_GreenChannel), Convert.ToInt32(m_BlueChannel), Convert.ToInt32(m_AlphaChannel)),
             });
         }

MaterialGraphProject/Assets/UnityShaderEditor/Editor/Data/Nodes/Channel/SwizzleNode.cs

                     return;
 
                 m_RedChannel = value;
-                if (onModified != null)
-                {
-                    onModified(this, ModificationScope.Node);
-                }
+                Dirty(ModificationScope.Node);
             }
         }
 
                     return;
 
                 m_GreenChannel = value;
-                if (onModified != null)
-                {
-                    onModified(this, ModificationScope.Node);
-                }
+                Dirty(ModificationScope.Node);
             }
         }
 
                     return;
 
                 m_BlueChannel = value;
-                if (onModified != null)
-                {
-                    onModified(this, ModificationScope.Node);
-                }
+                Dirty(ModificationScope.Node);
             }
         }
 
                     return;
 
                 m_AlphaChannel = value;
-                if (onModified != null)
-                {
-                    onModified(this, ModificationScope.Node);
-                }
+                Dirty(ModificationScope.Node);
             }
         }
 
             base.CollectPreviewMaterialProperties(properties);
             // Encode swizzle values into an integer
             var value = ((int)redChannel) | ((int)greenChannel << 2) | ((int)blueChannel << 4) | ((int)alphaChannel << 6);
-            properties.Add(new PreviewProperty
+            properties.Add(new PreviewProperty(PropertyType.Float)
-                propType = PropertyType.Float,
                 floatValue = value
             });
         }

MaterialGraphProject/Assets/UnityShaderEditor/Editor/Data/Nodes/GeometryNode.cs

                     return;
 
                 m_Space = value;
-                if (onModified != null)
-                {
-                    onModified(this, ModificationScope.Graph);
-                }
+                Dirty(ModificationScope.Graph);
             }
         }
 

MaterialGraphProject/Assets/UnityShaderEditor/Editor/Data/Nodes/Input/Basic/ColorNode.cs

                     return;
 
                 m_Color = value;
-                if (onModified != null)
-                {
-                    onModified(this, ModificationScope.Node);
-                }
+                Dirty(ModificationScope.Node);
             }
         }
 
 
         public override void CollectPreviewMaterialProperties(List<PreviewProperty> properties)
         {
-            properties.Add(new PreviewProperty
+            properties.Add(new PreviewProperty(PropertyType.Color)
-                propType = PropertyType.Color,
                 colorValue = color
             });
         }
-            var prop = new ColorShaderProperty();
-            prop.value = color;
-            return prop;
+            return new ColorShaderProperty { value = color };
         }
 
         public int outputSlotId { get { return OutputSlotId; } }

MaterialGraphProject/Assets/UnityShaderEditor/Editor/Data/Nodes/Input/Basic/ConstantNode.cs

                     return;
 
                 m_constant = value;
-                if (onModified != null)
-                {
-                    onModified(this, ModificationScope.Graph);
-                }
+                Dirty(ModificationScope.Graph);
             }
         }
 

MaterialGraphProject/Assets/UnityShaderEditor/Editor/Data/Nodes/Input/Basic/Vector1Node.cs

 
                 m_Value = value;
 
-                if (onModified != null)
-                    onModified(this, ModificationScope.Node);
+                Dirty(ModificationScope.Node);
             }
         }
 
 
                  m_floatType = value;
 
-                 if (onModified != null)
-                     onModified(this, ModificationScope.Node);
+                 Dirty(ModificationScope.Node);
              }
          }*/
 
 
                   m_rangeValues = value;
 
-                  if (onModified != null)
-                      onModified(this, ModificationScope.Node);
+                  Dirty(ModificationScope.Node);
               }
           }
   */
 
         public override void CollectPreviewMaterialProperties(List<PreviewProperty> properties)
         {
-            properties.Add(new PreviewProperty()
+            properties.Add(new PreviewProperty(PropertyType.Float)
-                propType = PropertyType.Float,
                 floatValue = m_Value
             });
         }
-            var prop = new FloatShaderProperty();
-            prop.value = value;
-            return prop;
+            return new FloatShaderProperty { value = value };
         }
 
         public int outputSlotId { get { return OutputSlotId; } }

MaterialGraphProject/Assets/UnityShaderEditor/Editor/Data/Nodes/Input/Basic/Vector2Node.cs

 
                 m_Value = value;
 
-                if (onModified != null)
-                    onModified(this, ModificationScope.Node);
+                Dirty(ModificationScope.Node);
             }
         }
 
 
         public override void CollectPreviewMaterialProperties(List<PreviewProperty> properties)
         {
-            properties.Add(new PreviewProperty()
+            properties.Add(new PreviewProperty(PropertyType.Vector2)
-                propType = PropertyType.Vector2,
                 vector4Value = m_Value
             });
         }
-            var prop = new Vector2ShaderProperty();
-            prop.value = value;
-            return prop;
+            return new Vector2ShaderProperty { value = value };
         }
 
         public int outputSlotId { get { return OutputSlotId; } }

MaterialGraphProject/Assets/UnityShaderEditor/Editor/Data/Nodes/Input/Basic/Vector3Node.cs

 
                 m_Value = value;
 
-                if (onModified != null)
-                    onModified(this, ModificationScope.Node);
+                Dirty(ModificationScope.Node);
             }
         }
 
 
         public override void CollectPreviewMaterialProperties(List<PreviewProperty> properties)
         {
-            properties.Add(new PreviewProperty()
+            properties.Add(new PreviewProperty(PropertyType.Vector3)
-                propType = PropertyType.Vector3,
                 vector4Value = m_Value
             });
         }
-            var prop = new Vector3ShaderProperty();
-            prop.value = value;
-            return prop;
+            return new Vector3ShaderProperty { value = value };
         }
 
         public int outputSlotId { get { return OutputSlotId; } }

MaterialGraphProject/Assets/UnityShaderEditor/Editor/Data/Nodes/Input/Basic/Vector4Node.cs

 
                 m_Value = value;
 
-                if (onModified != null)
-                    onModified(this, ModificationScope.Node);
+                Dirty(ModificationScope.Node);
             }
         }
 
 
         public override void CollectPreviewMaterialProperties(List<PreviewProperty> properties)
         {
-            properties.Add(new PreviewProperty()
+            properties.Add(new PreviewProperty(PropertyType.Vector4)
-                propType = PropertyType.Vector4,
                 vector4Value = m_Value
             });
         }
-            var prop = new Vector4ShaderProperty();
-            prop.value = value;
-            return prop;
+            return new Vector4ShaderProperty { value = value };
         }
 
         public int outputSlotId { get { return OutputSlotId; } }

MaterialGraphProject/Assets/UnityShaderEditor/Editor/Data/Nodes/Input/Geometry/ScreenPositionNode.cs

                     return;
 
                 m_ScreenSpaceType = value;
-                if (onModified != null)
-                {
-                    onModified(this, ModificationScope.Graph);
-                }
+                Dirty(ModificationScope.Graph);
             }
         }
 

MaterialGraphProject/Assets/UnityShaderEditor/Editor/Data/Nodes/Input/Geometry/UVNode.cs

                     return;
 
                 m_OutputChannel = value;
-                if (onModified != null)
-                {
-                    onModified(this, ModificationScope.Graph);
-                }
+                Dirty(ModificationScope.Graph);
             }
         }
 

MaterialGraphProject/Assets/UnityShaderEditor/Editor/Data/Nodes/Input/Matrix/Matrix2Node.cs

             if (value == row)
                 return;
             row = value;
-            if (onModified != null)
-                onModified(this, ModificationScope.Graph);
+            Dirty(ModificationScope.Graph);
         }
 
         public Matrix2Node()

MaterialGraphProject/Assets/UnityShaderEditor/Editor/Data/Nodes/Input/Matrix/Matrix3Node.cs

             if (value == row)
                 return;
             row = value;
-            if (onModified != null)
-                onModified(this, ModificationScope.Graph);
+            Dirty(ModificationScope.Graph);
         }
 
         public Matrix3Node()

MaterialGraphProject/Assets/UnityShaderEditor/Editor/Data/Nodes/Input/Matrix/Matrix4Node.cs

             if (value == row)
                 return;
             row = value;
-            if (onModified != null)
-                onModified(this, ModificationScope.Graph);
+            Dirty(ModificationScope.Graph);
         }
 
         public Matrix4Node()

MaterialGraphProject/Assets/UnityShaderEditor/Editor/Data/Nodes/Input/Matrix/TransformationMatrixNode.cs

                     return;
 
                 m_matrix = value;
-                if (onModified != null)
-                {
-                    onModified(this, ModificationScope.Graph);
-                }
+                Dirty(ModificationScope.Graph);
             }
         }
 

MaterialGraphProject/Assets/UnityShaderEditor/Editor/Data/Nodes/Input/PropertyNode.cs

 
                 UpdateNode();
 
-                if (onModified != null)
-                {
-                    onModified(this, ModificationScope.Topological);
-                }
+                Dirty(ModificationScope.Topological);
             }
         }
 

MaterialGraphProject/Assets/UnityShaderEditor/Editor/Data/Nodes/Input/Texture/CubemapAssetNode.cs

                 if (m_Cubemap.cubemap == value)
                     return;
                 m_Cubemap.cubemap = value;
-                if (onModified != null)
-                {
-                    onModified(this, ModificationScope.Node);
-                }
+                Dirty(ModificationScope.Node);
             }
         }
 
 
         public override void CollectPreviewMaterialProperties(List<PreviewProperty> properties)
         {
-            properties.Add(new PreviewProperty
+            properties.Add(new PreviewProperty(PropertyType.Cubemap)
-                propType = PropertyType.Cubemap,
                 cubemapValue = cubemap
             });
         }
-            var prop = new CubemapShaderProperty();
-            prop.value = m_Cubemap;
+            var prop = new CubemapShaderProperty { value = m_Cubemap };
             if (cubemap != null)
                 prop.displayName = cubemap.name;
             return prop;

MaterialGraphProject/Assets/UnityShaderEditor/Editor/Data/Nodes/Input/Texture/SampleTexture2DNode.cs

                     return;
 
                 m_TextureType = value;
-                if (onModified != null)
-                {
-                    onModified(this, ModificationScope.Graph);
-                }
+                Dirty(ModificationScope.Graph);
             }
         }
 

MaterialGraphProject/Assets/UnityShaderEditor/Editor/Data/Nodes/Input/Texture/SamplerStateNode.cs

                     return;
 
                 m_filter = value;
-                if (onModified != null)
-                {
-                    onModified(this, ModificationScope.Graph);
-                }
+                Dirty(ModificationScope.Graph);
             }
         }
 
                     return;
 
                 m_wrap = value;
-                if (onModified != null)
-                {
-                    onModified(this, ModificationScope.Graph);
-                }
+                Dirty(ModificationScope.Graph);
             }
         }
 

MaterialGraphProject/Assets/UnityShaderEditor/Editor/Data/Nodes/Input/Texture/Texture2DAssetNode.cs

                 if (m_Texture.texture == value)
                     return;
                 m_Texture.texture = value;
-                if (onModified != null)
-                {
-                    onModified(this, ModificationScope.Node);
-                }
+                Dirty(ModificationScope.Node);
             }
         }
 
 
         public override void CollectPreviewMaterialProperties(List<PreviewProperty> properties)
         {
-            properties.Add(new PreviewProperty
+            properties.Add(new PreviewProperty(PropertyType.Texture)
-                propType = PropertyType.Texture,
                 textureValue = texture
             });
         }
-            var prop = new TextureShaderProperty();
-            prop.value = m_Texture;
+            var prop = new TextureShaderProperty { value = m_Texture };
             if (texture != null)
                 prop.displayName = texture.name;
             return prop;

MaterialGraphProject/Assets/UnityShaderEditor/Editor/Data/Nodes/Math/Advanced/ExponentialNode.cs

                     return;
 
                 m_ExponentialBase = value;
-                if (onModified != null)
-                {
-                    onModified(this, ModificationScope.Graph);
-                }
+                Dirty(ModificationScope.Graph);
             }
         }
 

MaterialGraphProject/Assets/UnityShaderEditor/Editor/Data/Nodes/Math/Advanced/LogNode.cs

                     return;
 
                 m_LogBase = value;
-                if (onModified != null)
-                {
-                    onModified(this, ModificationScope.Graph);
-                }
+                Dirty(ModificationScope.Graph);
             }
         }
 

MaterialGraphProject/Assets/UnityShaderEditor/Editor/Data/Nodes/Math/Advanced/ReciprocalNode.cs

                     return;
 
                 m_ReciprocalMethod = value;
-                if (onModified != null)
-                {
-                    onModified(this, ModificationScope.Graph);
-                }
+                Dirty(ModificationScope.Graph);
             }
         }
 

MaterialGraphProject/Assets/UnityShaderEditor/Editor/Data/Nodes/Math/Vector/TransformNode.cs

                 if (Equals(m_Conversion, value))
                     return;
                 m_Conversion = value;
-                if (onModified != null)
-                    onModified(this, ModificationScope.Graph);
+                Dirty(ModificationScope.Graph);
             }
         }
 
             return conversion.from.ToNeededCoordinateSpace();
         }
     }
-}
+}

MaterialGraphProject/Assets/UnityShaderEditor/Editor/Data/Nodes/UV/RotateNode.cs

                     return;
 
                 m_Unit = value;
-                if (onModified != null)
-                {
-                    onModified(this, ModificationScope.Graph);
-                }
+                Dirty(ModificationScope.Graph);
             }
         }
 

MaterialGraphProject/Assets/UnityShaderEditor/Editor/Data/Nodes/Utility/SubGraphNode.cs

                 m_SerializedSubGraph = EditorJsonUtility.ToJson(helper, true);
                 UpdateSlots();
 
-                if (onModified != null)
-                    onModified(this, ModificationScope.Topological);
+                Dirty(ModificationScope.Topological);
             }
         }
 #else

MaterialGraphProject/Assets/UnityShaderEditor/Editor/Data/Util/GenerationResults.cs

         public List<PropertyCollector.TextureInfo> configuredTextures;
         public PreviewMode previewMode { get; set; }
         public FloatShaderProperty outputIdProperty { get; set; }
-        public Dictionary<Guid, int> ids { get; set; }
-            ids = new Dictionary<Guid, int>();
         }
     }
 }

MaterialGraphProject/Assets/UnityShaderEditor/Editor/Data/Util/GraphUtil.cs

                 shaderProperties,
                 requirements,
                 mode,
-                outputIdProperty: results.outputIdProperty,
-                ids: results.ids);
+                outputIdProperty: results.outputIdProperty);
 
             var finalBuilder = new ShaderStringBuilder();
             finalBuilder.AppendLine(@"Shader ""{0}""", name);
             string functionName = "PopulateSurfaceData",
             string surfaceDescriptionName = "SurfaceDescription",
             FloatShaderProperty outputIdProperty = null,
-            Dictionary<Guid, int> ids = null,
             IEnumerable<MaterialSlot> slots = null)
         {
             if (graph == null)
 
             graph.CollectShaderProperties(shaderProperties, mode);
 
-            var currentId = -1;
             foreach (var activeNode in activeNodeList.OfType<AbstractMaterialNode>())
             {
                 if (activeNode is IGeneratesFunction)
                 {
                     var outputSlot = activeNode.GetOutputSlots<MaterialSlot>().FirstOrDefault();
                     if (outputSlot != null)
-                    {
-                        currentId++;
-                        ids[activeNode.guid] = currentId;
-                        surfaceDescriptionFunction.AddShaderChunk(String.Format("if ({0} == {1}) {{ surface.PreviewOutput = {2}; return surface; }}", outputIdProperty.referenceName, currentId, ShaderGenerator.AdaptNodeOutputForPreview(activeNode, outputSlot.id, activeNode.GetVariableNameForSlot(outputSlot.id))), false);
-                    }
+                        surfaceDescriptionFunction.AddShaderChunk(String.Format("if ({0} == {1}) {{ surface.PreviewOutput = {2}; return surface; }}", outputIdProperty.referenceName, activeNode.tempId.index, ShaderGenerator.AdaptNodeOutputForPreview(activeNode, outputSlot.id, activeNode.GetVariableNameForSlot(outputSlot.id))), false);
                 }
 
                 activeNode.CollectShaderProperties(shaderProperties, mode);

MaterialGraphProject/Assets/UnityShaderEditor/Editor/Drawing/Inspector/GraphInspectorView.cs

         VisualElement m_PropertyItems;
         VisualElement m_LayerItems;
         ObjectField m_PreviewMeshPicker;
-        AbstractNodeEditorView m_EditorView;
 
         PreviewTextureView m_PreviewTextureView;
 
             Quaternion previewRotation = Quaternion.Euler(m_PreviewScrollPosition.y, 0, 0) * Quaternion.Euler(0, m_PreviewScrollPosition.x, 0);
             m_Graph.previewData.rotation = previewRotation;
 
-            masterNode.onModified(masterNode, ModificationScope.Node);
+            masterNode.Dirty(ModificationScope.Node);
         }
 
         void OnAddProperty()
         {
             Mesh changedMesh = changeEvent.newValue as Mesh;
 
-            masterNode.onModified(masterNode, ModificationScope.Node);
+            masterNode.Dirty(ModificationScope.Node);
 
             if (m_Graph.previewData.serializedMesh.mesh != changedMesh)
             {

MaterialGraphProject/Assets/UnityShaderEditor/Editor/Drawing/Inspector/ShaderPropertyView.cs

         void NotifyNodes()
         {
             foreach (var node in graph.GetNodes<PropertyNode>())
-                node.onModified(node, ModificationScope.Node);
+                node.Dirty(ModificationScope.Node);
         }
 
         void FloatField()

MaterialGraphProject/Assets/UnityShaderEditor/Editor/Drawing/MaterialGraphEditWindow.cs

                 graphEditorView.HandleGraphChanges();
                 graphObject.graph.ClearChanges();
             }
-            catch (Exception)
+            catch (Exception e)
+                Debug.LogException(e);
                 throw;
             }
         }

MaterialGraphProject/Assets/UnityShaderEditor/Editor/Drawing/PreviewManager.cs

 using System;
 using System.Collections.Generic;
-using System.Diagnostics;
 using System.IO;
 using System.Linq;
 using UnityEngine;
     public class PreviewManager : IDisposable
     {
         AbstractMaterialGraph m_Graph;
-        Dictionary<Guid, PreviewRenderData> m_RenderDatas = new Dictionary<Guid, PreviewRenderData>();
-        Dictionary<Guid, PreviewShaderData> m_ShaderDatas = new Dictionary<Guid, PreviewShaderData>();
+        List<PreviewRenderData> m_RenderDatas = new List<PreviewRenderData>();
-        HashSet<Guid> m_DirtyPreviews = new HashSet<Guid>();
-        HashSet<Guid> m_DirtyShaders = new HashSet<Guid>();
-        HashSet<Guid> m_TimeDependentPreviews = new HashSet<Guid>();
+        List<Identifier> m_Identifiers = new List<Identifier>();
+        IndexSet m_DirtyPreviews = new IndexSet();
+        IndexSet m_DirtyShaders = new IndexSet();
+        IndexSet m_TimeDependentPreviews = new IndexSet();
-        string m_UberShaderString;
-        Dictionary<Guid, int> m_UberShaderIds;
-        FloatShaderProperty m_OutputIdProperty;
+        string m_OutputIdName;
 
         public PreviewRenderData masterRenderData
         {
             m_SceneResources = new PreviewSceneResources();
             m_UberShader = ShaderUtil.CreateShaderAsset(k_EmptyShader);
             m_UberShader.hideFlags = HideFlags.HideAndDontSave;
-            m_UberShaderIds = new Dictionary<Guid, int>();
             m_MasterRenderData = new PreviewRenderData
             {
                 renderTexture = new RenderTexture(400, 400, 16, RenderTextureFormat.ARGB32, RenderTextureReadWrite.Default) { hideFlags = HideFlags.HideAndDontSave }
                 AddPreview(node);
         }
 
-        public PreviewRenderData GetPreview(INode node)
+        public PreviewRenderData GetPreview(AbstractMaterialNode node)
-            return m_RenderDatas[node.guid];
+            return m_RenderDatas[node.tempId.index];
-            PreviewShaderData shaderData;
-            if (!m_ShaderDatas.TryGetValue(node.guid, out shaderData))
+            var shaderData = new PreviewShaderData
-                shaderData = new PreviewShaderData
-                {
-                    node = node
-                };
-                m_ShaderDatas[node.guid] = shaderData;
-            }
-            var previewData = new PreviewRenderData
+                node = node
+            };
+            var renderData = new PreviewRenderData
-            if (m_RenderDatas.ContainsKey(node.guid))
-            {
-                Debug.LogWarningFormat("A preview already exists for {0} {1}", node.name, node.guid);
-                RemovePreview(node);
-            }
-            m_RenderDatas.Add(node.guid, previewData);
-            m_DirtyShaders.Add(node.guid);
+            Set(m_Identifiers, node.tempId, node.tempId);
+            Set(m_RenderDatas, node.tempId, renderData);
+            m_DirtyShaders.Add(node.tempId.index);
-                m_TimeDependentPreviews.Add(node.guid);
+                m_TimeDependentPreviews.Add(node.tempId.index);
-            {
-            }
-        }
-
-        void RemovePreview(INode node)
-        {
-            node.onModified -= OnNodeModified;
-            m_RenderDatas.Remove(node.guid);
-            m_TimeDependentPreviews.Remove(node.guid);
-            m_DirtyPreviews.Remove(node.guid);
-            m_DirtyShaders.Remove(node.guid);
-
-            if (masterRenderData.shaderData != null && masterRenderData.shaderData.node == node)
-                masterRenderData.shaderData = m_ShaderDatas.Values.FirstOrDefault(x => x.node is IMasterNode);
-                m_DirtyShaders.Add(node.guid);
+                m_DirtyShaders.Add(node.tempId.index);
-                m_DirtyPreviews.Add(node.guid);
+                m_DirtyPreviews.Add(node.tempId.index);
-                m_TimeDependentPreviews.Add(node.guid);
+                m_TimeDependentPreviews.Add(node.tempId.index);
-                m_TimeDependentPreviews.Remove(node.guid);
+                m_TimeDependentPreviews.Remove(node.tempId.index);
-        Stack<Guid> m_Wavefront = new Stack<Guid>();
+        Stack<Identifier> m_Wavefront = new Stack<Identifier>();
-        void PropagateNodeSet(HashSet<Guid> nodeGuidSet, bool forward = true, IEnumerable<Guid> initialWavefront = null)
+        void PropagateNodeSet(IndexSet nodeSet, bool forward = true, IEnumerable<Identifier> initialWavefront = null)
-            foreach (var guid in initialWavefront ?? nodeGuidSet)
-                m_Wavefront.Push(guid);
+            if (initialWavefront != null)
+            {
+                foreach (var id in initialWavefront)
+                    m_Wavefront.Push(id);
+            }
+            else
+            {
+                foreach (var index in nodeSet)
+                    m_Wavefront.Push(m_Identifiers[index]);
+            }
-                var nodeGuid = m_Wavefront.Pop();
-                var node = m_Graph.GetNodeFromGuid(nodeGuid);
+                var index = m_Wavefront.Pop();
+                var node = m_Graph.GetNodeFromTempId(index);
                 if (node == null)
                     continue;
 
                         // We look at each node we feed into.
                         var connectedSlot = forward ? edge.inputSlot : edge.outputSlot;
                         var connectedNodeGuid = connectedSlot.nodeGuid;
+                        var connectedNode = m_Graph.GetNodeFromGuid(connectedNodeGuid);
-                        if (nodeGuidSet.Contains(connectedNodeGuid))
+                        if (nodeSet.Contains(connectedNode.tempId.index))
-                        nodeGuidSet.Add(connectedNodeGuid);
-                        m_Wavefront.Push(connectedNodeGuid);
+                        nodeSet.Add(connectedNode.tempId.index);
+                        m_Wavefront.Push(connectedNode.tempId);
-        HashSet<Guid> m_PropertyNodeGuids = new HashSet<Guid>();
-        List<PreviewProperty> m_PreviewProperties = new List<PreviewProperty>();
-                RemovePreview(node);
+                DestroyPreview(node.tempId);
-                m_DirtyShaders.Add(edge.inputSlot.nodeGuid);
+            {
+                var node = m_Graph.GetNodeFromGuid(edge.inputSlot.nodeGuid);
+                if (node != null)
+                    m_DirtyShaders.Add(node.tempId.index);
+            }
-                m_DirtyShaders.Add(edge.inputSlot.nodeGuid);
+            {
+                var node = m_Graph.GetNodeFromGuid(edge.inputSlot.nodeGuid);
+                if (node != null)
+                    m_DirtyShaders.Add(node.tempId.index);
+            }
+        List<PreviewProperty> m_PreviewProperties = new List<PreviewProperty>();
-        HashSet<Guid> m_NodesWith3DPreview = new HashSet<Guid>();
+        IndexSet m_PropertyNodes = new IndexSet();
-            if (m_DirtyShaders.Any())
-            {
-                m_NodesWith3DPreview.Clear();
-                foreach (var node in m_Graph.GetNodes<AbstractMaterialNode>())
-                {
-                    if (node.previewMode == PreviewMode.Preview3D)
-                        m_NodesWith3DPreview.Add(node.guid);
-                }
-                PropagateNodeSet(m_NodesWith3DPreview);
-                PropagateNodeSet(m_DirtyShaders);
-
-                var masterNodes = new List<INode>();
-                var uberNodes = new List<INode>();
-                foreach (var guid in m_DirtyShaders)
-                {
-                    var node = m_Graph.GetNodeFromGuid(guid);
-                    if (node == null)
-                        continue;
-                    if (node is IMasterNode)
-                        masterNodes.Add(node);
-                    else
-                        uberNodes.Add(node);
-                }
-                var count = Math.Min(uberNodes.Count, 1) + masterNodes.Count;
+            UpdateShaders();
-                try
-                {
-                    var sw = new Stopwatch();
-                    sw.Start();
-                    var i = 0;
-                    EditorUtility.DisplayProgressBar("Shader Graph", string.Format("Compiling preview shaders ({0}/{1})", i, count), 0f);
-                    foreach (var node in masterNodes)
-                    {
-                        UpdateShader(node.guid);
-                        i++;
-                        EditorUtility.DisplayProgressBar("Shader Graph", string.Format("Compiling preview shaders ({0}/{1})", i, count), 0f);
-                    }
-                    if (uberNodes.Count > 0)
-                    {
-                        m_UberShaderIds.Clear();
-                        var results = m_Graph.GetUberPreviewShader();
-                        m_UberShaderString = results.shader;
-                        m_OutputIdProperty = results.outputIdProperty;
-                        m_UberShaderIds = results.ids;
-                        ShaderUtil.UpdateShaderAsset(m_UberShader, m_UberShaderString);
-                        File.WriteAllText(Application.dataPath + "/../UberShader.shader", (m_UberShaderString ?? "null").Replace("UnityEngine.MaterialGraph", "Generated"));
-                        bool uberShaderHasError = false;
-                        if (MaterialGraphAsset.ShaderHasError(m_UberShader))
-                        {
-                            var errors = MaterialGraphAsset.GetShaderErrors(m_UberShader);
-                            var message = new ShaderStringBuilder();
-                            message.AppendLine(@"Preview shader for graph has {0} error{1}:", errors.Length, errors.Length != 1 ? "s" : "");
-                            foreach (var error in errors)
-                            {
-                                INode node = null;
-                                try
-                                {
-                                    node = results.sourceMap.FindNode(error.line);
-                                }
-                                catch (Exception)
-                                {
-                                    Debug.LogWarning("ERROR");
-                                    continue;
-                                }
-                                message.AppendLine("{0} in {3} at line {1} (on {2})", error.message, error.line, error.platform, node != null ? string.Format("node {0} ({1})", node.name, node.guid) : "graph");
-                                message.AppendLine(error.messageDetails);
-                                message.AppendNewLine();
-                            }
-                            Debug.LogWarning(message.ToString());
-                            ShaderUtil.ClearShaderErrors(m_UberShader);
-                            ShaderUtil.UpdateShaderAsset(m_UberShader, k_EmptyShader);
-                            uberShaderHasError = true;
-                        }
-
-                        foreach (var node in uberNodes)
-                        {
-                            PreviewShaderData shaderData;
-                            if (!m_ShaderDatas.TryGetValue(node.guid, out shaderData))
-                                continue;
-                            shaderData.previewMode = m_NodesWith3DPreview.Contains(node.guid) ? PreviewMode.Preview3D : PreviewMode.Preview2D;
-                            shaderData.shader = m_UberShader;
-                            shaderData.hasError = uberShaderHasError;
-                        }
-                        i++;
-                        EditorUtility.DisplayProgressBar("Shader Graph", string.Format("Compiling preview shaders ({0}/{1})", i, count), 0f);
-                    }
-                    sw.Stop();
-                    //Debug.LogFormat("Compiled preview shaders in {0} seconds", sw.Elapsed.TotalSeconds);
-                }
-                finally
-                {
-                    EditorUtility.ClearProgressBar();
-                }
-
-                m_DirtyPreviews.UnionWith(m_DirtyShaders);
-                m_DirtyShaders.Clear();
-            }
-
+            // Union time dependent previews into dirty previews
-            m_PropertyNodeGuids.Clear();
-            foreach (var nodeGuid in m_DirtyPreviews)
-                m_PropertyNodeGuids.Add(nodeGuid);
-            PropagateNodeSet(m_PropertyNodeGuids, false);
+            m_PropertyNodes.Clear();
+            m_PropertyNodes.UnionWith(m_DirtyPreviews);
+            PropagateNodeSet(m_PropertyNodes, false);
-            var outputIdName = m_OutputIdProperty != null ? m_OutputIdProperty.referenceName : null;
-            m_PreviewPropertyBlock.SetFloat(outputIdName, -1);
-            foreach (var nodeGuid in m_PropertyNodeGuids)
+            m_PreviewPropertyBlock.SetFloat(m_OutputIdName, -1);
+            foreach (var index in m_PropertyNodes)
-                var node = m_Graph.GetNodeFromGuid<AbstractMaterialNode>(nodeGuid);
+                var node = m_Graph.GetNodeFromTempId(m_Identifiers[index]) as AbstractMaterialNode;
                 if (node == null)
                     continue;
                 node.CollectPreviewMaterialProperties(m_PreviewProperties);
                 foreach (var previewProperty in m_PreviewProperties)
-                {
-                    if (previewProperty.propType == PropertyType.Texture && previewProperty.textureValue != null)
-                        m_PreviewPropertyBlock.SetTexture(previewProperty.name, previewProperty.textureValue);
-                    else if (previewProperty.propType == PropertyType.Cubemap && previewProperty.cubemapValue != null)
-                        m_PreviewPropertyBlock.SetTexture(previewProperty.name, previewProperty.cubemapValue);
-                    else if (previewProperty.propType == PropertyType.Color)
-                        m_PreviewPropertyBlock.SetColor(previewProperty.name, previewProperty.colorValue);
-                    else if (previewProperty.propType == PropertyType.Vector2)
-                        m_PreviewPropertyBlock.SetVector(previewProperty.name, previewProperty.vector4Value);
-                    else if (previewProperty.propType == PropertyType.Vector3)
-                        m_PreviewPropertyBlock.SetVector(previewProperty.name, previewProperty.vector4Value);
-                    else if (previewProperty.propType == PropertyType.Vector4)
-                        m_PreviewPropertyBlock.SetVector(previewProperty.name, previewProperty.vector4Value);
-                    else if (previewProperty.propType == PropertyType.Float)
-                        m_PreviewPropertyBlock.SetFloat(previewProperty.name, previewProperty.floatValue);
-                }
+                    m_PreviewPropertyBlock.SetPreviewProperty(previewProperty);
-            foreach (var nodeGuid in m_DirtyPreviews)
+            foreach (var i in m_DirtyPreviews)
-                PreviewRenderData renderData;
-                if (!m_RenderDatas.TryGetValue(nodeGuid, out renderData))
-                    continue;
+                var renderData = m_RenderDatas[i];
                 if (renderData.shaderData.shader == null)
                 {
                     renderData.texture = null;
                     continue;
                 }
 
-                if (renderData.shaderData.previewMode == PreviewMode.Preview2D)
+                if (renderData.previewMode == PreviewMode.Preview2D)
-
-            if (masterRenderData.shaderData != null && m_DirtyPreviews.Contains(masterRenderData.shaderData.node.guid))
-                m_RenderList3D.Add(masterRenderData);
 
             m_RenderList3D.Sort((data1, data2) => data1.shaderData.shader.GetInstanceID().CompareTo(data2.shaderData.shader.GetInstanceID()));
             m_RenderList2D.Sort((data1, data2) => data1.shaderData.shader.GetInstanceID().CompareTo(data2.shaderData.shader.GetInstanceID()));
             m_SceneResources.camera.orthographic = true;
 
             foreach (var renderData in m_RenderList2D)
-            {
-                int outputId;
-                if (m_UberShaderIds.TryGetValue(renderData.shaderData.node.guid, out outputId))
-                    m_PreviewPropertyBlock.SetFloat(outputIdName, outputId);
-                if (m_PreviewMaterial.shader != renderData.shaderData.shader)
-                    m_PreviewMaterial.shader = renderData.shaderData.shader;
-                m_SceneResources.camera.targetTexture = renderData.renderTexture;
-                var previousRenderTexure = RenderTexture.active;
-                RenderTexture.active = renderData.renderTexture;
-                GL.Clear(true, true, Color.black);
-                Graphics.Blit(Texture2D.whiteTexture, renderData.renderTexture, m_SceneResources.checkerboardMaterial);
-                Graphics.DrawMesh(m_SceneResources.quad, Matrix4x4.identity, m_PreviewMaterial, 1, m_SceneResources.camera, 0, m_PreviewPropertyBlock, ShadowCastingMode.Off, false, null, false);
-                var previousUseSRP = Unsupported.useScriptableRenderPipeline;
-                Unsupported.useScriptableRenderPipeline = false;
-                m_SceneResources.camera.Render();
-                Unsupported.useScriptableRenderPipeline = previousUseSRP;
-                RenderTexture.active = previousRenderTexure;
-                renderData.texture = renderData.renderTexture;
-            }
+                RenderPreview(renderData, m_SceneResources.quad, Matrix4x4.identity);
 
             // Render 3D previews
             m_SceneResources.camera.transform.position = -Vector3.forward * 5;
             foreach (var renderData in m_RenderList3D)
+                RenderPreview(renderData, m_SceneResources.sphere, Matrix4x4.identity);
+
+            var renderMasterPreview = masterRenderData.shaderData != null && m_DirtyPreviews.Contains(masterRenderData.shaderData.node.tempId.index);
+            if (renderMasterPreview)
-                int outputId;
-                if (m_UberShaderIds.TryGetValue(renderData.shaderData.node.guid, out outputId))
-                    m_PreviewPropertyBlock.SetFloat(outputIdName, outputId);
-                if (m_PreviewMaterial.shader != renderData.shaderData.shader)
-                    m_PreviewMaterial.shader = renderData.shaderData.shader;
-                m_SceneResources.camera.targetTexture = renderData.renderTexture;
-                var previousRenderTexure = RenderTexture.active;
-                RenderTexture.active = renderData.renderTexture;
-                GL.Clear(true, true, Color.black);
-                Graphics.Blit(Texture2D.whiteTexture, renderData.renderTexture, m_SceneResources.checkerboardMaterial);
-                var mesh = (renderData == masterRenderData && m_Graph.previewData.serializedMesh.mesh) ? m_Graph.previewData.serializedMesh.mesh :  m_SceneResources.sphere;
-                Quaternion rotation = (renderData == masterRenderData) ? m_Graph.previewData.rotation : Quaternion.identity;
-                Matrix4x4 previewTransform = Matrix4x4.identity;
-
-                if (renderData == masterRenderData)
-                {
-                    previewTransform *= Matrix4x4.Rotate(rotation);
-                    previewTransform *= Matrix4x4.Scale(Vector3.one * (Vector3.one).magnitude / mesh.bounds.size.magnitude);
-                    previewTransform *= Matrix4x4.Translate(-mesh.bounds.center);
-                }
-
-                Graphics.DrawMesh(mesh, previewTransform, m_PreviewMaterial, 1, m_SceneResources.camera, 0, m_PreviewPropertyBlock, ShadowCastingMode.Off, false, null, false);
-
-                var previousUseSRP = Unsupported.useScriptableRenderPipeline;
-                Unsupported.useScriptableRenderPipeline = renderData.shaderData.node is IMasterNode;
-                m_SceneResources.camera.Render();
-                Unsupported.useScriptableRenderPipeline = previousUseSRP;
-                RenderTexture.active = previousRenderTexure;
-                renderData.texture = renderData.renderTexture;
+                var mesh = m_Graph.previewData.serializedMesh.mesh ? m_Graph.previewData.serializedMesh.mesh :  m_SceneResources.sphere;
+                var previewTransform = Matrix4x4.Rotate(m_Graph.previewData.rotation);
+                previewTransform *= Matrix4x4.Scale(Vector3.one * (Vector3.one).magnitude / mesh.bounds.size.magnitude);
+                previewTransform *= Matrix4x4.Translate(-mesh.bounds.center);
+                RenderPreview(masterRenderData, mesh, previewTransform);
             }
 
             m_SceneResources.light0.enabled = false;
                 renderData.NotifyPreviewChanged();
             foreach (var renderData in m_RenderList3D)
                 renderData.NotifyPreviewChanged();
+            if (renderMasterPreview)
+                masterRenderData.NotifyPreviewChanged();
 
             m_RenderList2D.Clear();
             m_RenderList3D.Clear();
-        void UpdateShader(Guid nodeGuid)
+        IndexSet m_NodesWith3DPreview = new IndexSet();
+
+        void UpdateShaders()
-            var node = m_Graph.GetNodeFromGuid<AbstractMaterialNode>(nodeGuid);
+            if (m_DirtyShaders.Any())
+            {
+                PropagateNodeSet(m_DirtyShaders);
+                m_NodesWith3DPreview.Clear();
+                foreach (var index in m_DirtyShaders)
+                {
+                    var node = (AbstractMaterialNode)m_Graph.GetNodeFromTempId(m_Identifiers[index]);
+                    if (node.previewMode == PreviewMode.Preview3D)
+                        m_NodesWith3DPreview.Add(node.tempId.index);
+                }
+                PropagateNodeSet(m_NodesWith3DPreview);
+                foreach (var index in m_DirtyShaders)
+                {
+                    var renderData = m_RenderDatas[index];
+                    renderData.previewMode = m_NodesWith3DPreview.Contains(renderData.shaderData.node.tempId.index) ? PreviewMode.Preview3D : PreviewMode.Preview2D;
+                }
+
+                var masterNodes = new List<MasterNode>();
+                var uberNodes = new List<INode>();
+                foreach (var index in m_DirtyShaders)
+                {
+                    var node = m_Graph.GetNodeFromTempId(m_Identifiers[index]);
+                    if (node == null)
+                        continue;
+                    var masterNode = node as MasterNode;
+                    if (masterNode != null)
+                        masterNodes.Add(masterNode);
+                    else
+                        uberNodes.Add(node);
+                }
+                var count = Math.Min(uberNodes.Count, 1) + masterNodes.Count;
+
+                try
+                {
+                    var i = 0;
+                    EditorUtility.DisplayProgressBar("Shader Graph", string.Format("Compiling preview shaders ({0}/{1})", i, count), 0f);
+                    foreach (var node in masterNodes)
+                    {
+                        UpdateShader(node.tempId);
+                        i++;
+                        EditorUtility.DisplayProgressBar("Shader Graph", string.Format("Compiling preview shaders ({0}/{1})", i, count), 0f);
+                    }
+                    if (uberNodes.Count > 0)
+                    {
+                        var results = m_Graph.GetUberPreviewShader();
+                        m_OutputIdName = results.outputIdProperty.referenceName;
+                        ShaderUtil.UpdateShaderAsset(m_UberShader, results.shader);
+                        File.WriteAllText(Application.dataPath + "/../UberShader.shader", (results.shader ?? "null").Replace("UnityEngine.MaterialGraph", "Generated"));
+                        bool uberShaderHasError = false;
+                        if (MaterialGraphAsset.ShaderHasError(m_UberShader))
+                        {
+                            var errors = MaterialGraphAsset.GetShaderErrors(m_UberShader);
+                            var message = new ShaderStringBuilder();
+                            message.AppendLine(@"Preview shader for graph has {0} error{1}:", errors.Length, errors.Length != 1 ? "s" : "");
+                            foreach (var error in errors)
+                            {
+                                INode node;
+                                try
+                                {
+                                    node = results.sourceMap.FindNode(error.line);
+                                }
+                                catch (Exception e)
+                                {
+                                    Debug.LogException(e);
+                                    continue;
+                                }
+                                message.AppendLine("{0} in {3} at line {1} (on {2})", error.message, error.line, error.platform, node != null ? string.Format("node {0} ({1})", node.name, node.guid) : "graph");
+                                message.AppendLine(error.messageDetails);
+                                message.AppendNewLine();
+                            }
+                            Debug.LogWarning(message.ToString());
+                            ShaderUtil.ClearShaderErrors(m_UberShader);
+                            ShaderUtil.UpdateShaderAsset(m_UberShader, k_EmptyShader);
+                            uberShaderHasError = true;
+                        }
+
+                        foreach (var node in uberNodes)
+                        {
+                            var renderData = GetRenderData(node.tempId);
+                            if (renderData == null)
+                                continue;
+                            var shaderData = renderData.shaderData;
+                            shaderData.shader = m_UberShader;
+                            shaderData.hasError = uberShaderHasError;
+                        }
+                        i++;
+                        EditorUtility.DisplayProgressBar("Shader Graph", string.Format("Compiling preview shaders ({0}/{1})", i, count), 0f);
+                    }
+                }
+                finally
+                {
+                    EditorUtility.ClearProgressBar();
+                }
+
+                // Union dirty shaders into dirty previews
+                m_DirtyPreviews.UnionWith(m_DirtyShaders);
+                m_DirtyShaders.Clear();
+            }
+        }
+
+        void RenderPreview(PreviewRenderData renderData, Mesh mesh, Matrix4x4 transform)
+        {
+            m_PreviewPropertyBlock.SetFloat(m_OutputIdName, renderData.shaderData.node.tempId.index);
+            if (m_PreviewMaterial.shader != renderData.shaderData.shader)
+                m_PreviewMaterial.shader = renderData.shaderData.shader;
+            m_SceneResources.camera.targetTexture = renderData.renderTexture;
+            var previousRenderTexure = RenderTexture.active;
+            RenderTexture.active = renderData.renderTexture;
+            GL.Clear(true, true, Color.black);
+            Graphics.Blit(Texture2D.whiteTexture, renderData.renderTexture, m_SceneResources.checkerboardMaterial);
+
+            Graphics.DrawMesh(mesh, transform, m_PreviewMaterial, 1, m_SceneResources.camera, 0, m_PreviewPropertyBlock, ShadowCastingMode.Off, false, null, false);
+
+            var previousUseSRP = Unsupported.useScriptableRenderPipeline;
+            Unsupported.useScriptableRenderPipeline = renderData.shaderData.node is IMasterNode;
+            m_SceneResources.camera.Render();
+            Unsupported.useScriptableRenderPipeline = previousUseSRP;
+            RenderTexture.active = previousRenderTexure;
+            renderData.texture = renderData.renderTexture;
+        }
+
+        void UpdateShader(Identifier nodeId)
+        {
+            var node = m_Graph.GetNodeFromTempId(nodeId) as AbstractMaterialNode;
-            PreviewShaderData shaderData;
-            if (!m_ShaderDatas.TryGetValue(nodeGuid, out shaderData))
+            var renderData = Get(m_RenderDatas, nodeId);
+            if (renderData == null || renderData.shaderData == null)
-
-            shaderData.previewMode = m_NodesWith3DPreview.Contains(nodeGuid) ? PreviewMode.Preview3D : PreviewMode.Preview2D;
+            var shaderData = renderData.shaderData;
 
             if (!(node is IMasterNode) && (!node.hasPreview || NodeUtils.FindEffectiveShaderStage(node, true) == ShaderStage.Vertex))
             {
             }
         }
 
-        void DestroyPreview(Guid nodeGuid, PreviewRenderData previewRenderData)
+        void DestroyPreview(Identifier nodeId)
-            if (m_RenderDatas.Remove(nodeGuid))
+            var renderData = Get(m_RenderDatas, nodeId);
+            if (renderData != null)
-                if (previewRenderData.shaderData.shader != null)
-                    Object.DestroyImmediate(previewRenderData.shaderData.shader, true);
-                if (previewRenderData.renderTexture != null)
-                    Object.DestroyImmediate(previewRenderData.renderTexture, true);
-                var node = m_Graph.GetNodeFromGuid(nodeGuid);
+                if (renderData.shaderData.shader != null && renderData.shaderData.shader != m_UberShader)
+                    Object.DestroyImmediate(renderData.shaderData.shader, true);
+                if (renderData.renderTexture != null)
+                    Object.DestroyImmediate(renderData.renderTexture, true);
+                var node = renderData.shaderData.node;
-                m_DirtyPreviews.Remove(nodeGuid);
-                m_DirtyShaders.Remove(nodeGuid);
-                m_TimeDependentPreviews.Remove(nodeGuid);
-                previewRenderData.shaderData.shader = null;
-                previewRenderData.renderTexture = null;
-                previewRenderData.texture = null;
-                previewRenderData.onPreviewChanged = null;
+
+                m_TimeDependentPreviews.Remove(nodeId.index);
+                m_DirtyPreviews.Remove(nodeId.index);
+                m_DirtyPreviews.Remove(nodeId.index);
+                Set(m_RenderDatas, nodeId, null);
+                Set(m_Identifiers, nodeId, default(Identifier));
+
+                if (masterRenderData.shaderData != null && masterRenderData.shaderData.node == node)
+                    masterRenderData.shaderData = m_RenderDatas.Where(x => x != null && x.shaderData.node is IMasterNode).Select(x => x.shaderData).FirstOrDefault();
+
+                renderData.shaderData.shader = null;
+                renderData.renderTexture = null;
+                renderData.texture = null;
+                renderData.onPreviewChanged = null;
+            if (m_UberShader != null)
+            {
+                Object.DestroyImmediate(m_UberShader, true);
+                m_UberShader = null;
+            }
+            if (m_ErrorTexture != null)
+            {
+                Object.DestroyImmediate(m_ErrorTexture);
+                m_ErrorTexture = null;
+            }
+            {
-            m_PreviewMaterial = null;
+                m_PreviewMaterial = null;
+            }
+            {
-            m_SceneResources = null;
-            var previews = m_RenderDatas.ToList();
-            foreach (var kvp in previews)
-                DestroyPreview(kvp.Key, kvp.Value);
+                m_SceneResources = null;
+            }
+            foreach (var renderData in m_RenderDatas.ToList())
+                DestroyPreview(renderData.shaderData.node.tempId);
         }
 
         public void Dispose()
         }
     }
 }";
+
+        T Get<T>(List<T> list, Identifier id)
+        {
+            var existingId = Get(m_Identifiers, id.index);
+            if (existingId.valid && existingId.version != id.version)
+                throw new Exception("Identifier version mismatch");
+            return Get(list, id.index);
+        }
+
+        static T Get<T>(List<T> list, int index)
+        {
+            return index < list.Count ? list[index] : default(T);
+        }
+
+        void Set<T>(List<T> list, Identifier id, T value)
+        {
+            var existingId = Get(m_Identifiers, id.index);
+            if (existingId.valid && existingId.version != id.version)
+                throw new Exception("Identifier version mismatch");
+            Set(list, id.index, value);
+        }
+
+        static void Set<T>(List<T> list, int index, T value)
+        {
+            // Make sure the list is large enough for the index
+            for (var i = list.Count; i <= index; i++)
+                list.Add(default(T));
+            list[index] = value;
+        }
+
+        PreviewRenderData GetRenderData(Identifier id)
+        {
+            var value = Get(m_RenderDatas, id);
+            if (value != null && value.shaderData.node.tempId.version != id.version)
+                throw new Exception("Trying to access render data of a previous version of a node");
+            return value;
+        }
     }
 
     public delegate void OnPreviewChanged();
         public INode node { get; set; }
         public Shader shader { get; set; }
         public string shaderString { get; set; }
-        public PreviewMode previewMode { get; set; }
         public bool hasError { get; set; }
     }
 
         public RenderTexture renderTexture { get; set; }
         public Texture texture { get; set; }
+        public PreviewMode previewMode { get; set; }
         public OnPreviewChanged onPreviewChanged;
 
         public void NotifyPreviewChanged()

MaterialGraphProject/Assets/UnityShaderEditor/Editor/Drawing/Views/Slots/ColorRGBSlotControlView.cs

         {
             m_Slot.owner.owner.owner.RegisterCompleteObjectUndo("Color Change");
             m_Slot.value = new Vector3(evt.newValue.r, evt.newValue.g, evt.newValue.b);
-            if (m_Slot.owner.onModified != null)
-                m_Slot.owner.onModified(m_Slot.owner, ModificationScope.Node);
+            m_Slot.owner.Dirty(ModificationScope.Node);
         }
     }
 }

MaterialGraphProject/Assets/UnityShaderEditor/Editor/Drawing/Views/Slots/ColorSlotControlView.cs

         {
             m_Slot.owner.owner.owner.RegisterCompleteObjectUndo("Color Change");
             m_Slot.value = evt.newValue;
-            if (m_Slot.owner.onModified != null)
-                m_Slot.owner.onModified(m_Slot.owner, ModificationScope.Node);
+            m_Slot.owner.Dirty(ModificationScope.Node);
         }
     }
 }

MaterialGraphProject/Assets/UnityShaderEditor/Editor/Drawing/Views/Slots/CubemapSlotControlView.cs

             {
                 m_Slot.owner.owner.owner.RegisterCompleteObjectUndo("Change Cubemap");
                 m_Slot.cubemap = cubemap;
-                if (m_Slot.owner.onModified != null)
-                    m_Slot.owner.onModified(m_Slot.owner, ModificationScope.Node);
+                m_Slot.owner.Dirty(ModificationScope.Node);
             }
         }
     }

MaterialGraphProject/Assets/UnityShaderEditor/Editor/Drawing/Views/Slots/MultiFloatSlotControlView.cs

                     var value = m_Get();
                     value[index] = (float)evt.newValue;
                     m_Set(value);
-                    if (m_Node.onModified != null)
-                        m_Node.onModified(m_Node, ModificationScope.Node);
+                    m_Node.Dirty(ModificationScope.Node);
                     m_UndoGroup = -1;
                 });
             field.RegisterCallback<InputEvent>(evt =>
                     {
                         value[index] = newValue;
                         m_Set(value);
-                        if (m_Node.onModified != null)
-                            m_Node.onModified(m_Node, ModificationScope.Node);
+                        m_Node.Dirty(ModificationScope.Node);
                     }
                 });
             field.RegisterCallback<KeyDownEvent>(evt =>

MaterialGraphProject/Assets/UnityShaderEditor/Editor/Drawing/Views/Slots/TextureSlotControlView.cs

             {
                 m_Slot.owner.owner.owner.RegisterCompleteObjectUndo("Change Texture");
                 m_Slot.texture = texture;
-                if (m_Slot.owner.onModified != null)
-                    m_Slot.owner.onModified(m_Slot.owner, ModificationScope.Node);
+                m_Slot.owner.Dirty(ModificationScope.Node);
             }
         }
     }

MaterialGraphProject/Assets/UnityShaderEditor/Editor/Drawing/Views/Slots/UVSlotControlView.cs

             {
                 m_Slot.owner.owner.owner.RegisterCompleteObjectUndo("Change UV Channel");
                 m_Slot.channel = channel;
-                if (m_Slot.owner.onModified != null)
-                    m_Slot.owner.onModified(m_Slot.owner, ModificationScope.Graph);
+                m_Slot.owner.Dirty(ModificationScope.Graph);
             }
         }
     }

MaterialGraphProject/ProjectSettings/ProjectVersion.txt

-m_EditorVersion: 2018.1.0b1
+m_EditorVersion: 2018.1.0b2

MaterialGraphProject/Assets/UnityShaderEditor/Editor/Data/Util/Identifier.cs

+namespace UnityEditor.ShaderGraph
+{
+    public struct Identifier
+    {
+        uint m_Version;
+        int m_Index;
+
+        public Identifier(int index, uint version = 1)
+        {
+            m_Version = version;
+            m_Index = index;
+        }
+
+        public void IncrementVersion()
+        {
+            if (m_Version == uint.MaxValue)
+                m_Version = 1;
+            else
+                m_Version++;
+        }
+
+        public uint version
+        {
+            get { return m_Version; }
+        }
+
+        public int index
+        {
+            get { return m_Index; }
+        }
+
+        public bool valid
+        {
+            get { return m_Version != 0; }
+        }
+    }
+}

MaterialGraphProject/Assets/UnityShaderEditor/Editor/Data/Util/Identifier.cs.meta

+fileFormatVersion: 2
+guid: 084958a703164b0fa26e0667aaa1767f
+timeCreated: 1513937833

MaterialGraphProject/Assets/UnityShaderEditor/Editor/Util/IndexSet.cs

+using System;
+using System.Collections;
+using System.Collections.Generic;
+
+namespace UnityEditor.ShaderGraph.Drawing
+{
+    public sealed class IndexSet : ICollection<int>
+    {
+        List<uint> m_Masks = new List<uint>();
+
+        public IndexSet() { }
+
+        public IndexSet(IEnumerable<int> indices)
+        {
+            foreach (var index in indices)
+                Add(index);
+        }
+
+        public IEnumerator<int> GetEnumerator()
+        {
+            for (var i = 0; i < m_Masks.Count; i++)
+            {
+                var mask = m_Masks[i];
+                if (mask == 0)
+                    continue;
+                for (var j = 0; j < 32; j++)
+                {
+                    if ((mask & (1 << j)) > 0)
+                        yield return i * 32 + j;
+                }
+            }
+        }
+
+        IEnumerator IEnumerable.GetEnumerator()
+        {
+            return GetEnumerator();
+        }
+
+        public void UnionWith(IEnumerable<int> other)
+        {
+            var otherSet = other as IndexSet;
+            if (otherSet != null)
+            {
+                UnionWith(otherSet);
+            }
+            else
+            {
+                foreach (var index in other)
+                    Add(index);
+            }
+        }
+
+        public void UnionWith(IndexSet other)
+        {
+            for (var i = 0; i < Math.Min(m_Masks.Count, other.m_Masks.Count); i++)
+                m_Masks[i] |= other.m_Masks[i];
+            for (var i = m_Masks.Count; i < other.m_Masks.Count; i++)
+                m_Masks.Add(other.m_Masks[i]);
+        }
+
+        public void IntersectWith(IEnumerable<int> other)
+        {
+            IntersectWith(other as IndexSet ?? new IndexSet(other));
+        }
+
+        public void IntersectWith(IndexSet other)
+        {
+            for (var i = 0; i < Math.Min(m_Masks.Count, other.m_Masks.Count); i++)
+                m_Masks[i] &= other.m_Masks[i];
+        }
+
+        public void ExceptWith(IEnumerable<int> other)
+        {
+            var otherSet = other as IndexSet;
+            if (otherSet != null)
+            {
+                ExceptWith(otherSet);
+            }
+            else
+            {
+                foreach (var index in other)
+                    Remove(index);
+            }
+        }
+
+        public void ExceptWith(IndexSet other)
+        {
+            for (var i = 0; i < Math.Min(m_Masks.Count, other.m_Masks.Count); i++)
+                m_Masks[i] &= ~other.m_Masks[i];
+        }
+
+        public void SymmetricExceptWith(IEnumerable<int> other)
+        {
+            SymmetricExceptWith(other as IndexSet ?? new IndexSet(other));
+        }
+
+        public void SymmetricExceptWith(IndexSet other)
+        {
+            for (var i = 0; i < Math.Min(m_Masks.Count, other.m_Masks.Count); i++)
+                m_Masks[i] ^= other.m_Masks[i];
+        }
+
+        public bool IsSubsetOf(IEnumerable<int> other)
+        {
+            return IsSubsetOf(other as IndexSet ?? new IndexSet(other));
+        }
+
+        public bool IsSubsetOf(IndexSet other)
+        {
+            for (var i = 0; i < Math.Min(m_Masks.Count, other.m_Masks.Count); i++)
+            {
+                var mask = m_Masks[i];
+                var otherMask = other.m_Masks[i];
+                if ((mask & otherMask) != mask)
+                    return false;
+            }
+
+            for (var i = other.m_Masks.Count; i < m_Masks.Count; i++)
+            {
+                if (m_Masks[i] > 0)
+                    return false;
+            }
+
+            return true;
+        }
+
+        public bool IsSupersetOf(IEnumerable<int> other)
+        {
+            return IsSupersetOf(other as IndexSet ?? new IndexSet(other));
+        }
+
+        public bool IsSupersetOf(IndexSet other)
+        {
+            for (var i = 0; i < Math.Min(m_Masks.Count, other.m_Masks.Count); i++)
+            {
+                var otherMask = other.m_Masks[i];
+                var mask = m_Masks[i];
+                if ((otherMask & mask) != otherMask)
+                    return false;
+            }
+
+            for (var i = m_Masks.Count; i < other.m_Masks.Count; i++)
+            {
+                if (other.m_Masks[i] > 0)
+                    return false;
+            }
+
+            return true;
+        }
+
+        public bool IsProperSupersetOf(IEnumerable<int> other)
+        {
+            return IsProperSupersetOf(other as IndexSet ?? new IndexSet(other));
+        }
+
+        public bool IsProperSupersetOf(IndexSet other)
+        {
+            var isProper = false;
+
+            for (var i = 0; i < Math.Min(m_Masks.Count, other.m_Masks.Count); i++)
+            {
+                var mask = m_Masks[i];
+                var otherMask = other.m_Masks[i];
+                if ((otherMask & mask) != otherMask)
+                    return false;
+                if ((~otherMask & mask) > 0)
+                    isProper = true;
+            }
+
+            for (var i = m_Masks.Count; i < other.m_Masks.Count; i++)
+            {
+                if (other.m_Masks[i] > 0)
+                    return false;
+            }
+
+            if (!isProper)
+            {
+                for (var i = other.m_Masks.Count; i < m_Masks.Count; i++)
+                {
+                    if (m_Masks[i] > 0)
+                        return true;
+                }
+            }
+
+            return isProper;
+        }
+
+        public bool IsProperSubsetOf(IEnumerable<int> other)
+        {
+            return IsProperSubsetOf(other as IndexSet ?? new IndexSet(other));
+        }
+
+        public bool IsProperSubsetOf(IndexSet other)
+        {
+            var isProper = false;
+
+            for (var i = 0; i < Math.Min(m_Masks.Count, other.m_Masks.Count); i++)
+            {
+                var mask = m_Masks[i];
+                var otherMask = other.m_Masks[i];
+                if ((mask & otherMask) != mask)
+                    return false;
+                if ((~mask & otherMask) > 0)
+                    isProper = true;
+            }
+
+            for (var i = other.m_Masks.Count; i < m_Masks.Count; i++)
+            {
+                if (m_Masks[i] > 0)
+                    return false;
+            }
+
+            if (!isProper)
+            {
+                for (var i = m_Masks.Count; i < other.m_Masks.Count; i++)
+                {
+                    if (other.m_Masks[i] > 0)
+                        return true;
+                }
+            }
+
+            return isProper;
+        }
+
+        public bool Overlaps(IEnumerable<int> other)
+        {
+            var otherSet = other as IndexSet;
+            if (otherSet != null)
+                return Overlaps(otherSet);
+
+            foreach (var index in other)
+            {
+                if (Contains(index))
+                    return true;
+            }
+
+            return false;
+        }
+
+        public bool Overlaps(IndexSet other)
+        {
+            for (var i = 0; i < Math.Min(m_Masks.Count, other.m_Masks.Count); i++)
+            {
+                if ((m_Masks[i] & other.m_Masks[i]) > 0)
+                    return true;
+            }
+            return false;
+        }
+
+        public bool SetEquals(IEnumerable<int> other)
+        {
+            var otherSet = other as IndexSet;
+            if (otherSet != null)
+                return SetEquals(otherSet);
+
+            foreach (var index in other)
+            {
+                if (!Contains(index))
+                    return false;
+            }
+            return true;
+        }
+
+        public bool SetEquals(IndexSet other)
+        {
+            for (var i = 0; i < Math.Min(m_Masks.Count, other.m_Masks.Count); i++)
+            {
+                if (m_Masks[i] != other.m_Masks[i])
+                    return false;
+            }
+
+            for (var i = other.m_Masks.Count; i < m_Masks.Count; i++)
+            {
+                if (m_Masks[i] > 0)
+                    return false;
+            }
+
+            for (var i = m_Masks.Count; i < other.m_Masks.Count; i++)
+            {
+                if (other.m_Masks[i] > 0)
+                    return false;
+            }
+            return true;
+        }
+
+        public bool Add(int index)
+        {
+            var maskIndex = index >> 5;
+            var bitIndex = index & 31;
+
+            for (var i = m_Masks.Count; i <= maskIndex; i++)
+                m_Masks.Add(0);
+
+            var mask = (uint)1 << bitIndex;
+            var isNew = (m_Masks[maskIndex] & mask) == 0;
+            m_Masks[maskIndex] |= mask;
+            return isNew;
+        }
+
+        void ICollection<int>.Add(int index)
+        {
+            Add(index);
+        }
+
+        public void Clear()
+        {
+            for (var i = 0; i < m_Masks.Count; i++)
+                m_Masks[i] = 0;
+        }
+
+        public bool Contains(int index)
+        {
+            var maskIndex = index >> 5;
+            var bitIndex = index & 31;
+            return (m_Masks[maskIndex] & ((uint)1 << bitIndex)) > 0;
+        }
+
+        public void CopyTo(int[] array, int arrayIndex)
+        {
+            throw new NotImplementedException();
+        }
+
+        public bool Remove(int index)
+        {
+            var maskIndex = index >> 5;
+            var bitIndex = index & 31;
+            if (maskIndex >= m_Masks.Count)
+                return false;
+            var mask = (uint)1 << bitIndex;
+            var exists = (m_Masks[maskIndex] & mask) > 0;
+            m_Masks[maskIndex] &= ~mask;
+            return exists;
+        }
+
+        public int Count
+        {
+            get
+            {
+                var count = 0;
+                foreach (var mask in m_Masks)
+                {
+                    for (var j = 0; j < 32; j++)
+                    {
+                        if ((mask & (1 << j)) > 0)
+                            count++;
+                    }
+                }
+                return count;
+            }
+        }
+
+        public bool IsReadOnly
+        {
+            get { return false; }
+        }
+    }
+}

MaterialGraphProject/Assets/UnityShaderEditor/Editor/Util/IndexSet.cs.meta

+fileFormatVersion: 2
+guid: 41c67c52dd54464fa78d8ab286eb501b
+timeCreated: 1514376310

MaterialGraphProject/Assets/UnityShaderEditor/Editor/Drawing/Inspector/AbstractNodeEditorView.cs.meta

-fileFormatVersion: 2
-guid: fbedfe40df1243cabce79ccfd4906096
-timeCreated: 1504778276

MaterialGraphProject/Assets/UnityShaderEditor/Editor/Drawing/Inspector/NodeEditorHeaderView.cs.meta

-fileFormatVersion: 2
-guid: 157f3e805d124f169cf20967d94036b3
-timeCreated: 1504857315

MaterialGraphProject/Assets/UnityShaderEditor/Editor/Drawing/Inspector/StandardNodeEditorView.cs.meta

-fileFormatVersion: 2
-guid: 61b4edcdcc1949a29fa0b42e25241429
-timeCreated: 1503661486

MaterialGraphProject/Assets/UnityShaderEditor/Editor/Drawing/Inspector/SurfaceMasterNodeEditorView.cs.meta

-fileFormatVersion: 2
-guid: 6f830a3e1e834df09773f7ccaaac94d3
-timeCreated: 1504787084

MaterialGraphProject/Assets/UnityShaderEditor/Editor/Drawing/Inspector/AbstractNodeEditorView.cs

-using System;
-using UnityEngine;
-using UnityEngine.Experimental.UIElements;
-using UnityEditor.Graphing;
-
-namespace UnityEditor.ShaderGraph.Drawing.Inspector
-{
-    public abstract class AbstractNodeEditorView : VisualElement, IDisposable
-    {
-        public abstract INode node { get; set; }
-
-        public abstract void Dispose();
-    }
-}

MaterialGraphProject/Assets/UnityShaderEditor/Editor/Drawing/Inspector/NodeEditorHeaderView.cs

-using UnityEngine.Experimental.UIElements;
-
-namespace UnityEditor.ShaderGraph.Drawing.Inspector
-{
-    public class NodeEditorHeaderView : VisualElement
-    {
-        Label m_Title;
-        Label m_Type;
-
-        public NodeEditorHeaderView()
-        {
-            m_Title = new Label("") { name = "title" };
-            Add(m_Title);
-            Add(new Label("(") { name = "preType" });
-            m_Type = new Label("") { name = "type" };
-            Add(m_Type);
-            Add(new Label(")") { name = "postType" });
-        }
-
-        public string title
-        {
-            get { return m_Title.text; }
-            set { m_Title.text = value; }
-        }
-
-        public string type
-        {
-            get { return m_Type.text; }
-            set { m_Type.text = value; }
-        }
-    }
-}

MaterialGraphProject/Assets/UnityShaderEditor/Editor/Drawing/Inspector/StandardNodeEditorView.cs

-using UnityEditor.Graphing;
-
-namespace UnityEditor.ShaderGraph.Drawing.Inspector
-{
-    public class StandardNodeEditorView : AbstractNodeEditorView
-    {
-        NodeEditorHeaderView m_HeaderView;
-        AbstractMaterialNode m_Node;
-
-        public override INode node
-        {
-            get { return m_Node; }
-            set
-            {
-                if (value == m_Node)
-                    return;
-                if (m_Node != null)
-                    m_Node.onModified -= OnModified;
-                m_Node = value as AbstractMaterialNode;
-                OnModified(m_Node, ModificationScope.Node);
-                if (m_Node != null)
-                    m_Node.onModified += OnModified;
-            }
-        }
-
-        public override void Dispose()
-        {
-            if (m_Node != null)
-                m_Node.onModified -= OnModified;
-        }
-
-        public StandardNodeEditorView()
-        {
-            AddToClassList("nodeEditor");
-
-            m_HeaderView = new NodeEditorHeaderView() { type = "node" };
-            Add(m_HeaderView);
-        }
-
-        void OnModified(INode changedNode, ModificationScope scope)
-        {
-            if (node == null)
-                return;
-
-            m_HeaderView.title = node.name;
-        }
-    }
-}

MaterialGraphProject/Assets/UnityShaderEditor/Editor/Drawing/Inspector/SurfaceMasterNodeEditorView.cs

-using System;
-using UnityEngine.Experimental.UIElements;
-using UnityEditor.Graphing;
-using UnityEditor.ShaderGraph;
-
-namespace UnityEditor.ShaderGraph.Drawing.Inspector
-{
-    /* public class SurfaceMasterNodeEditorView : AbstractNodeEditorView
-     {
-         NodeEditorHeaderView m_HeaderView;
-         AbstractSurfaceMasterNode m_Node;
-
-         public override INode node
-         {
-             get { return m_Node; }
-             set
-             {
-                 if (value == m_Node)
-                     return;
-                 if (m_Node != null)
-                     m_Node.onModified -= OnModified;
-                 m_Node = value as AbstractSurfaceMasterNode;
-                 OnModified(m_Node, ModificationScope.Node);
-                 if (m_Node != null)
-                     m_Node.onModified += OnModified;
-             }
-         }
-
-         public override void Dispose()
-         {
-             if (m_Node != null)
-                 m_Node.onModified -= OnModified;
-         }
-
-         public SurfaceMasterNodeEditorView()
-         {
-             AddToClassList("nodeEditor");
-
-             m_HeaderView = new NodeEditorHeaderView { type = "node" };
-             Add(m_HeaderView);
-
-             var optionsSection = new VisualElement() { name = "surfaceOptions" };
-             optionsSection.AddToClassList("section");
-             {
-                 optionsSection.Add(new IMGUIContainer(OnGUIHandler));
-             }
-             Add(optionsSection);
-         }
-
-         void OnGUIHandler()
-         {
-             if (m_Node == null)
-                 return;
-
-             var options = m_Node.options;
-
-             EditorGUI.BeginChangeCheck();
-             options.srcBlend = (SurfaceMaterialOptions.BlendMode)EditorGUILayout.EnumPopup("Src Blend", options.srcBlend);
-             options.dstBlend = (SurfaceMaterialOptions.BlendMode)EditorGUILayout.EnumPopup("Dst Blend", options.dstBlend);
-             options.cullMode = (SurfaceMaterialOptions.CullMode)EditorGUILayout.EnumPopup("Cull Mode", options.cullMode);
-             options.zTest = (SurfaceMaterialOptions.ZTest)EditorGUILayout.EnumPopup("Z Test", options.zTest);
-             options.zWrite = (SurfaceMaterialOptions.ZWrite)EditorGUILayout.EnumPopup("Z Write", options.zWrite);
-             options.renderQueue = (SurfaceMaterialOptions.RenderQueue)EditorGUILayout.EnumPopup("Render Queue", options.renderQueue);
-             options.renderType = (SurfaceMaterialOptions.RenderType)EditorGUILayout.EnumPopup("Render Type", options.renderType);
-             if (EditorGUI.EndChangeCheck())
-                 m_Node.onModified(m_Node, ModificationScope.Graph);
-         }
-
-         void OnModified(INode changedNode, ModificationScope scope)
-         {
-             if (m_Node == null)
-                 return;
-
-             m_HeaderView.title = m_Node.name;
-             Dirty(ChangeType.Repaint);
-         }
-     }*/
-}