Massively decreased amount of allocations in preview rendering (~440 kB -> ~23 kB per frame)

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

 
         public bool RequiresMeshUV(UVChannel channel)
         {
-            foreach (var slot in GetInputSlots<MaterialSlot>().OfType<IMayRequireMeshUV>())
+            foreach (var slot in this.GetInputSlots<MaterialSlot>().OfType<IMayRequireMeshUV>())
             {
                 if (slot.RequiresMeshUV(channel))
                     return true;

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

                 m_RemovedProperties.Add(guid);
         }
 
+        static List<IEdge> s_TempEdges = new List<IEdge>();
+
         public void ReplacePropertyNodeWithConcreteNode(PropertyNode propertyNode)
         {
             var property = properties.FirstOrDefault(x => x.guid == propertyNode.propertyGuid);
                 node.drawState = propertyNode.drawState;
                 AddNodeNoValidate(node);
 
-                foreach (var edge in GetEdges(slot.slotReference).ToArray())
+                s_TempEdges.Clear();
+                GetEdges(slot.slotReference, s_TempEdges);
+                foreach (var edge in s_TempEdges)
                     ConnectNoValidate(node.GetSlotReference(slotId), edge.inputSlot);
 
                 RemoveNodeNoValidate(propertyNode);

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

             set { m_Name = value; }
         }
 
+        string m_DefaultReferenceName;
+
-                return string.IsNullOrEmpty(overrideReferenceName)
-                    ? string.Format("{0}_{1}", propertyType, GuidEncoder.Encode(guid))
-                    : overrideReferenceName;
+                if (string.IsNullOrEmpty(overrideReferenceName))
+                {
+                    if (string.IsNullOrEmpty(m_DefaultReferenceName))
+                        m_DefaultReferenceName = string.Format("{0}_{1}", propertyType, GuidEncoder.Encode(guid));
+                    return m_DefaultReferenceName;
+                }
+                return overrideReferenceName;
             }
         }
 

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

         {
             return new PreviewProperty
             {
-                m_Name = referenceName,
-                m_PropType = PropertyType.Color,
-                m_Color = value
+                name = referenceName,
+                propType = PropertyType.Color,
+                colorValue = value
             };
         }
     }

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

         {
             var pp = new PreviewProperty
             {
-                m_Name = name,
-                m_PropType = PropertyType.Cubemap,
-                m_Cubemap = cubemap
+                name = name,
+                propType = PropertyType.Cubemap,
+                cubemapValue = cubemap
             };
             return pp;
         }

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

         {
             return new PreviewProperty()
             {
-                m_Name = referenceName,
-                m_PropType = PropertyType.Cubemap,
-                m_Cubemap = value.cubemap
+                name = referenceName,
+                propType = PropertyType.Cubemap,
+                cubemapValue = value.cubemap
             };
         }
     }

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

         {
             var pp = new PreviewProperty
             {
-                m_Name = name,
-                m_PropType = ConvertConcreteSlotValueTypeToPropertyType(concreteValueType),
-                m_Vector4 = new Vector4(value.x, value.y, value.z, value.w),
-                m_Float = value.x,
-                m_Color = new Vector4(value.x, value.x, value.z, value.w),
+                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),
             };
             return pp;
         }

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

         {
             return new PreviewProperty()
             {
-                m_Name = referenceName,
-                m_PropType = PropertyType.Float,
-                m_Float = value
+                name = referenceName,
+                propType = PropertyType.Float,
+                floatValue = value
             };
         }
     }

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

 
         public virtual PreviewProperty GetPreviewProperty(string name)
         {
-            return null;
+            return default(PreviewProperty);
         }
 
         public abstract void CopyValuesFrom(MaterialSlot foundSlot);

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

 
 namespace UnityEditor.ShaderGraph
 {
-    public class PreviewProperty
+    public struct PreviewProperty
-        public string m_Name;
-        public PropertyType m_PropType;
+        public string name;
+        public PropertyType propType;
-        public Color m_Color;
-        public Texture m_Texture;
-        public Cubemap m_Cubemap;
-        public Vector4 m_Vector4;
-        public float m_Float;
+        public Color colorValue;
+        public Texture textureValue;
+        public Cubemap cubemapValue;
+        public Vector4 vector4Value;
+        public float floatValue;
     }
 }

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

-using System;
+using System;
 using UnityEngine;
 
 namespace UnityEditor.ShaderGraph
 
         public override PreviewProperty GetPreviewMaterialProperty()
         {
-            return null;
+            return default(PreviewProperty);
         }
     }
 }

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

 namespace UnityEditor.ShaderGraph
 {
     [Serializable]
-    public class SerializableTexture
+    public class SerializableTexture : ISerializationCallbackReceiver
     {
         [SerializeField]
         private string m_SerializedTexture;
             public Texture texture;
         }
 
+        Texture m_Texture;
+
-                if (string.IsNullOrEmpty(m_SerializedTexture))
-                    return null;
-
-                var tex = new TextureHelper();
-                EditorJsonUtility.FromJsonOverwrite(m_SerializedTexture, tex);
-                return tex.texture;
+                if (m_Texture == null && !string.IsNullOrEmpty(m_SerializedTexture))
+                {
+                    var tex = new TextureHelper();
+                    EditorJsonUtility.FromJsonOverwrite(m_SerializedTexture, tex);
+                    m_Texture = tex.texture;
+                    m_SerializedTexture = null;
+                }
+                return m_Texture;
-            set
-            {
-                if (texture == value)
-                    return;
+            set { m_Texture = value; }
+        }
-                var tex = new TextureHelper();
-                tex.texture = value;
-                m_SerializedTexture = EditorJsonUtility.ToJson(tex, true);
-            }
+        public void OnBeforeSerialize()
+        {
+            var tex = new TextureHelper { texture = texture };
+            m_SerializedTexture = EditorJsonUtility.ToJson(tex, true);
+        }
+
+        public void OnAfterDeserialize()
+        {
         }
     }
 }

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

         {
             var pp = new PreviewProperty
             {
-                m_Name = name,
-                m_PropType = PropertyType.Texture,
-                m_Texture = texture
+                name = name,
+                propType = PropertyType.Texture,
+                textureValue = texture
             };
             return pp;
         }

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

-using System;
+using System;
 using System.Text;
 using UnityEngine;
 
         {
             return new PreviewProperty()
             {
-                m_Name = referenceName,
-                m_PropType = PropertyType.Texture,
-                m_Texture = value.texture
+                name = referenceName,
+                propType = PropertyType.Texture,
+                textureValue = value.texture
             };
         }
     }

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

         {
             var pp = new PreviewProperty
             {
-                m_Name = name,
-                m_PropType = ConvertConcreteSlotValueTypeToPropertyType(concreteValueType),
-                m_Vector4 = new Vector4(value, value, value, value),
-                m_Float = value,
-                m_Color = new Vector4(value, value, value, value),
+                name = name,
+                propType = ConvertConcreteSlotValueTypeToPropertyType(concreteValueType),
+                vector4Value = new Vector4(value, value, value, value),
+                floatValue = value,
+                colorValue = new Vector4(value, value, value, value),
             };
             return pp;
         }

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

         {
             var pp = new PreviewProperty
             {
-                m_Name = name,
-                m_PropType = ConvertConcreteSlotValueTypeToPropertyType(concreteValueType),
-                m_Vector4 = new Vector4(value.x, value.y, 0, 0),
-                m_Float = value.x,
-                m_Color = new Vector4(value.x, value.x, 0, 0),
+                name = name,
+                propType = ConvertConcreteSlotValueTypeToPropertyType(concreteValueType),
+                vector4Value = new Vector4(value.x, value.y, 0, 0),
+                floatValue = value.x,
+                colorValue = new Vector4(value.x, value.x, 0, 0),
             };
             return pp;
         }

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

         {
             return new PreviewProperty()
             {
-                m_Name = referenceName,
-                m_PropType = PropertyType.Vector2,
-                m_Vector4 = value
+                name = referenceName,
+                propType = PropertyType.Vector2,
+                vector4Value = value
             };
         }
     }

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

         {
             var pp = new PreviewProperty
             {
-                m_Name = name,
-                m_PropType = ConvertConcreteSlotValueTypeToPropertyType(concreteValueType),
-                m_Vector4 = new Vector4(value.x, value.y, value.z, 0),
-                m_Float = value.x,
-                m_Color = new Vector4(value.x, value.x, value.z, 0),
+                name = name,
+                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),
             };
             return pp;
         }

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

         {
             return new PreviewProperty()
             {
-                m_Name = referenceName,
-                m_PropType = PropertyType.Vector3,
-                m_Vector4 = value
+                name = referenceName,
+                propType = PropertyType.Vector3,
+                vector4Value = value
             };
         }
     }

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

         {
             var pp = new PreviewProperty
             {
-                m_Name = name,
-                m_PropType = ConvertConcreteSlotValueTypeToPropertyType(concreteValueType),
-                m_Vector4 = new Vector4(value.x, value.y, value.z, value.w),
-                m_Float = value.x,
-                m_Color = new Vector4(value.x, value.x, value.z, value.w),
+                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),
             };
             return pp;
         }

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

         {
             return new PreviewProperty()
             {
-                m_Name = referenceName,
-                m_PropType = PropertyType.Vector4,
-                m_Vector4 = value
+                name = referenceName,
+                propType = PropertyType.Vector4,
+                vector4Value = value
             };
         }
     }

MaterialGraphProject/Assets/UnityShaderEditor/Editor/Data/Interfaces/IMayRequireBitangent.cs

+using UnityEditor.Graphing;
+
+    }
+
+    public static class MayRequireBitangentExtensions
+    {
+        public static NeededCoordinateSpace RequiresBitangent(this ISlot slot)
+        {
+            var mayRequireBitangent = slot as IMayRequireBitangent;
+            return mayRequireBitangent != null ? mayRequireBitangent.RequiresBitangent() : NeededCoordinateSpace.None;
+        }
     }
 }

MaterialGraphProject/Assets/UnityShaderEditor/Editor/Data/Interfaces/IMayRequireNormal.cs

+using UnityEditor.Graphing;
+
+    }
+
+    public static class MayRequireNormalExtensions
+    {
+        public static NeededCoordinateSpace RequiresNormal(this ISlot slot)
+        {
+            var mayRequireNormal = slot as IMayRequireNormal;
+            return mayRequireNormal != null ? mayRequireNormal.RequiresNormal() : NeededCoordinateSpace.None;
+        }
     }
 }

MaterialGraphProject/Assets/UnityShaderEditor/Editor/Data/Interfaces/IMayRequirePosition.cs

+using UnityEditor.Graphing;
+
+    }
+
+    public static class MayRequirePositionExtensions
+    {
+        public static NeededCoordinateSpace RequiresPosition(this ISlot slot)
+        {
+            var mayRequirePosition = slot as IMayRequirePosition;
+            return mayRequirePosition != null ? mayRequirePosition.RequiresPosition() : NeededCoordinateSpace.None;
+        }
     }
 }

MaterialGraphProject/Assets/UnityShaderEditor/Editor/Data/Interfaces/IMayRequireTangent.cs

+using UnityEditor.Graphing;
+
+    }
+
+    public static class MayRequireTangentExtensions
+    {
+        public static NeededCoordinateSpace RequiresTangent(this ISlot slot)
+        {
+            var mayRequireTangent = slot as IMayRequireTangent;
+            return mayRequireTangent != null ? mayRequireTangent.RequiresTangent() : NeededCoordinateSpace.None;
+        }
     }
 }

MaterialGraphProject/Assets/UnityShaderEditor/Editor/Data/Interfaces/IMayRequireTime.cs

+using UnityEditor.Graphing;
+
+    }
+
+
+    public static class MayRequireTimeExtensions
+    {
+        public static bool RequiresTime(this INode node)
+        {
+            var mayRequireTime = node as IMayRequireTime;
+            return mayRequireTime != null && mayRequireTime.RequiresTime();
+        }
     }
 }

MaterialGraphProject/Assets/UnityShaderEditor/Editor/Data/Interfaces/IMayRequireViewDirection.cs

+using UnityEditor.Graphing;
+
+    }
+
+    public static class MayRequireViewDirectionExtensions
+    {
+        public static NeededCoordinateSpace RequiresViewDirection(this ISlot slot)
+        {
+            var mayRequireViewDirection = slot as IMayRequireViewDirection;
+            return mayRequireViewDirection != null ? mayRequireViewDirection.RequiresViewDirection() : NeededCoordinateSpace.None;
+        }
     }
 }

MaterialGraphProject/Assets/UnityShaderEditor/Editor/Data/Interfaces/NeededCoordinateSpace.cs

-using System;
+using System;
+using System.Linq;
 
 namespace UnityEditor.ShaderGraph
 {
 
     public static class CoordinateSpaceNameExtensions
     {
+        static int s_SpaceCount = Enum.GetValues(typeof(CoordinateSpace)).Length;
+        static int s_InterpolatorCount = Enum.GetValues(typeof(InterpolatorType)).Length;
+        static string[] s_VariableNames = new string[s_SpaceCount * s_InterpolatorCount];
+
-            return string.Format("{0}Space{1}", space, type);
+            var index = (int)space * s_SpaceCount + (int)type;
+            if (string.IsNullOrEmpty(s_VariableNames[index]))
+                s_VariableNames[index] = string.Format("{0}Space{1}", space, type);
+            return s_VariableNames[index];
         }
 
         public static NeededCoordinateSpace ToNeededCoordinateSpace(this CoordinateSpace space)

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

     [Serializable]
     public abstract class AbstractMaterialNode : SerializableNode, IGenerateProperties
     {
+        protected static List<MaterialSlot> s_TempSlots = new List<MaterialSlot>();
+        protected static List<IEdge> s_TempEdges = new List<IEdge>();
+
         public enum OutputPrecision
         {
             @fixed,
             protected set { m_HasError = value; }
         }
 
+        string m_DefaultVariableName;
+        string m_NameForDefaultVariableName;
+        Guid m_GuidForDefaultVariableName;
+
+        string defaultVariableName
+        {
+            get
+            {
+                if (m_NameForDefaultVariableName != name || m_GuidForDefaultVariableName != guid)
+                {
+                    m_DefaultVariableName = string.Format("{0}_{1}", GetHLSLSafeName(name), GuidEncoder.Encode(guid));
+                    m_NameForDefaultVariableName = name;
+                    m_GuidForDefaultVariableName = guid;
+                }
+                return m_DefaultVariableName;
+            }
+        }
+
         protected AbstractMaterialNode()
         {
             version = 0;
         {
-            foreach (var inputSlot in GetInputSlots<MaterialSlot>())
+            foreach (var inputSlot in this.GetInputSlots<MaterialSlot>())
             {
                 var edges = owner.GetEdges(inputSlot.slotReference);
                 if (edges.Any())
 
             // all children nodes needs to be updated first
             // so do that here
-            foreach (var inputSlot in GetInputSlots<MaterialSlot>())
+            var slots = ListPool<MaterialSlot>.Get();
+            GetInputSlots(slots);
+            foreach (var inputSlot in slots)
             {
                 inputSlot.hasError = false;
 
                         isInError = true;
                 }
             }
+            ListPool<MaterialSlot>.Release(slots);
-            foreach (var inputSlot in GetInputSlots<MaterialSlot>())
+            s_TempSlots.Clear();
+            GetInputSlots(s_TempSlots);
+            foreach (var inputSlot in s_TempSlots)
             {
                 // if there is a connection
                 var edges = owner.GetEdges(inputSlot.slotReference).ToList();
             foreach (var skippedSlot in skippedDynamicSlots)
                 skippedSlot.SetConcreteType(dynamicType);
 
-            var inputError = GetInputSlots<MaterialSlot>().Any(x => x.hasError);
+            s_TempSlots.Clear();
+            GetInputSlots(s_TempSlots);
+            var inputError = s_TempSlots.Any(x => x.hasError);
-            foreach (var outputSlot in GetOutputSlots<MaterialSlot>())
+            s_TempSlots.Clear();
+            GetOutputSlots(s_TempSlots);
+            foreach (var outputSlot in s_TempSlots)
             {
                 outputSlot.hasError = false;
 
             }
 
             isInError |= inputError;
-            isInError |= GetOutputSlots<MaterialSlot>().Any(x => x.hasError);
+            s_TempSlots.Clear();
+            GetOutputSlots(s_TempSlots);
+            isInError |= s_TempSlots.Any(x => x.hasError);
             isInError |= CalculateNodeHasError();
             hasError = isInError;
 
 
         public virtual void CollectPreviewMaterialProperties(List<PreviewProperty> properties)
         {
-            var validSlots = GetInputSlots<MaterialSlot>().ToArray();
-
-            for (var index = 0; index < validSlots.Length; index++)
+            s_TempSlots.Clear();
+            GetInputSlots(s_TempSlots);
+            foreach (var s in s_TempSlots)
-                var s = validSlots[index];
-                var edges = owner.GetEdges(s.slotReference);
-                if (edges.Any())
+                s_TempEdges.Clear();
+                owner.GetEdges(s.slotReference, s_TempEdges);
+                if (s_TempEdges.Any())
-                if (item == null)
+                if (item.name == null)
                     continue;
 
                 properties.Add(item);
             var slot = FindSlot<MaterialSlot>(slotId);
             if (slot == null)
                 throw new ArgumentException(string.Format("Attempting to use MaterialSlot({0}) on node of type {1} where this slot can not be found", slotId, this), "slotId");
-            return "_" + GetVariableNameForNode() + "_" + GetHLSLSafeName(slot.shaderOutputName);
+            return string.Format("_{0}_{1}", GetVariableNameForNode(), GetHLSLSafeName(slot.shaderOutputName));
-            return GetHLSLSafeName(name) + "_" + GuidEncoder.Encode(guid);
+            return defaultVariableName;
         }
 
         public static string GetHLSLSafeName(string input)

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

 
             properties.Add(new PreviewProperty()
             {
-                m_Name = string.Format("_{0}_Red", GetVariableNameForNode()),
-                m_PropType = PropertyType.Vector3,
-                m_Vector4 = channelMixer.outRed
+                name = string.Format("_{0}_Red", GetVariableNameForNode()),
+                propType = PropertyType.Vector3,
+                vector4Value = channelMixer.outRed
-                m_Name = string.Format("_{0}_Green", GetVariableNameForNode()),
-                m_PropType = PropertyType.Vector3,
-                m_Vector4 = channelMixer.outGreen
+                name = string.Format("_{0}_Green", GetVariableNameForNode()),
+                propType = PropertyType.Vector3,
+                vector4Value = channelMixer.outGreen
-                m_Name = string.Format("_{0}_Blue", GetVariableNameForNode()),
-                m_PropType = PropertyType.Vector3,
-                m_Vector4 = channelMixer.outBlue
+                name = string.Format("_{0}_Blue", GetVariableNameForNode()),
+                propType = PropertyType.Vector3,
+                vector4Value = channelMixer.outBlue
             });
         }
 

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

 
             properties.Add(new PreviewProperty()
             {
-                m_Name = string.Format("_{0}_Flip", GetVariableNameForNode()),
-                m_PropType = PropertyType.Vector4,
-                m_Vector4 = new Vector4(Convert.ToInt32(m_RedChannel), Convert.ToInt32(m_GreenChannel), Convert.ToInt32(m_BlueChannel), Convert.ToInt32(m_AlphaChannel)),
+                name = string.Format("_{0}_Flip", GetVariableNameForNode()),
+                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/CodeFunctionNode.cs

 
         public void GenerateNodeCode(ShaderGenerator visitor, GenerationMode generationMode)
         {
-            foreach (var outSlot in GetOutputSlots<MaterialSlot>())
+            s_TempSlots.Clear();
+            GetOutputSlots(s_TempSlots);
+            foreach (var outSlot in s_TempSlots)
             {
                 visitor.AddShaderChunk(GetParamTypeName(outSlot) + " " + GetVariableNameForSlot(outSlot.id) + ";", true);
             }
-            foreach (var slot in GetSlots<MaterialSlot>().OrderBy(x => x.id))
+            s_TempSlots.Clear();
+            GetSlots(s_TempSlots);
+            s_TempSlots.Sort((slot1, slot2) => slot1.id.CompareTo(slot2.id));
+            foreach (var slot in s_TempSlots)
             {
                 if (!first)
                 {
         {
             string header = "void " + GetFunctionName() + "(";
 
+            s_TempSlots.Clear();
+            GetSlots(s_TempSlots);
+            s_TempSlots.Sort((slot1, slot2) => slot1.id.CompareTo(slot2.id));
-            foreach (var slot in GetSlots<MaterialSlot>().OrderBy(x => x.id))
+            foreach (var slot in s_TempSlots)
             {
                 if (!first)
                     header += ", ";
                 return string.Empty;
 
             result = result.Replace("{precision}", precision.ToString());
-            foreach (var slot in GetSlots<MaterialSlot>())
+            s_TempSlots.Clear();
+            GetSlots(s_TempSlots);
+            foreach (var slot in s_TempSlots)
             {
                 var toReplace = string.Format("{{slot{0}dimension}}", slot.id);
                 var replacement = GetSlotDimension(slot.concreteValueType);
         public NeededCoordinateSpace RequiresNormal()
         {
             var binding = NeededCoordinateSpace.None;
-            foreach (var slot in GetInputSlots<MaterialSlot>().OfType<IMayRequireNormal>())
+            s_TempSlots.Clear();
+            GetInputSlots(s_TempSlots);
+            foreach (var slot in s_TempSlots)
                 binding |= slot.RequiresNormal();
             return binding;
         }
             var binding = NeededCoordinateSpace.None;
-            foreach (var slot in GetInputSlots<MaterialSlot>().OfType<IMayRequireViewDirection>())
+            s_TempSlots.Clear();
+            GetInputSlots(s_TempSlots);
+            foreach (var slot in s_TempSlots)
                 binding |= slot.RequiresViewDirection();
             return binding;
         }
+            s_TempSlots.Clear();
+            GetInputSlots(s_TempSlots);
-            foreach (var slot in GetInputSlots<MaterialSlot>().OfType<IMayRequirePosition>())
+            foreach (var slot in s_TempSlots)
                 binding |= slot.RequiresPosition();
             return binding;
         }
+            s_TempSlots.Clear();
+            GetInputSlots(s_TempSlots);
-            foreach (var slot in GetInputSlots<MaterialSlot>().OfType<IMayRequireTangent>())
+            foreach (var slot in s_TempSlots)
                 binding |= slot.RequiresTangent();
             return binding;
         }
+            s_TempSlots.Clear();
+            GetInputSlots(s_TempSlots);
-            foreach (var slot in GetInputSlots<MaterialSlot>().OfType<IMayRequireBitangent>())
+            foreach (var slot in s_TempSlots)
                 binding |= slot.RequiresBitangent();
             return binding;
         }
-            foreach (var slot in GetInputSlots<MaterialSlot>().OfType<IMayRequireMeshUV>())
+            s_TempSlots.Clear();
+            GetInputSlots(s_TempSlots);
+            foreach (var slot in s_TempSlots)
             {
                 if (slot.RequiresMeshUV(channel))
                     return true;
 
         public bool RequiresScreenPosition()
         {
-            foreach (var slot in GetInputSlots<MaterialSlot>().OfType<IMayRequireScreenPosition>())
+            s_TempSlots.Clear();
+            GetInputSlots(s_TempSlots);
+            foreach (var slot in s_TempSlots)
             {
                 if (slot.RequiresScreenPosition())
                     return true;
 
         public bool RequiresVertexColor()
         {
-            foreach (var slot in GetInputSlots<MaterialSlot>().OfType<IMayRequireVertexColor>())
+            s_TempSlots.Clear();
+            GetInputSlots(s_TempSlots);
+            foreach (var slot in s_TempSlots)
             {
                 if (slot.RequiresVertexColor())
                     return true;

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

         {
             properties.Add(new PreviewProperty
             {
-                m_Name = GetVariableNameForNode(),
-                m_PropType = PropertyType.Color,
-                m_Color = color
+                name = GetVariableNameForNode(),
+                propType = PropertyType.Color,
+                colorValue = color
             });
         }
 

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

         {
             properties.Add(new PreviewProperty()
             {
-                m_Name = GetVariableNameForNode(),
-                m_PropType = PropertyType.Float,
-                m_Float = m_Value
+                name = GetVariableNameForNode(),
+                propType = PropertyType.Float,
+                floatValue = m_Value
             });
         }
 

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

         {
             properties.Add(new PreviewProperty()
             {
-                m_Name = GetVariableNameForNode(),
-                m_PropType = PropertyType.Vector2,
-                m_Vector4 = m_Value
+                name = GetVariableNameForNode(),
+                propType = PropertyType.Vector2,
+                vector4Value = m_Value
             });
         }
 

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

         {
             properties.Add(new PreviewProperty()
             {
-                m_Name = GetVariableNameForNode(),
-                m_PropType = PropertyType.Vector3,
-                m_Vector4 = m_Value
+                name = GetVariableNameForNode(),
+                propType = PropertyType.Vector3,
+                vector4Value = m_Value
             });
         }
 

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

         {
             properties.Add(new PreviewProperty()
             {
-                m_Name = GetVariableNameForNode(),
-                m_PropType = PropertyType.Vector4,
-                m_Vector4 = m_Value
+                name = GetVariableNameForNode(),
+                propType = PropertyType.Vector4,
+                vector4Value = m_Value
             });
         }
 

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

 
 namespace UnityEditor.ShaderGraph
 {
-    public interface IMayRequireScreenPosition
-    {
-        bool RequiresScreenPosition();
-    }
-
     public enum ScreenSpaceType
     {
         Default,

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

 
 namespace UnityEditor.ShaderGraph
 {
-    interface IMayRequireMeshUV
-    {
-        bool RequiresMeshUV(UVChannel channel);
-    }
-
     [Title("Input", "Geometry", "UV")]
     public class UVNode : AbstractMaterialNode, IGeneratesBodyCode, IMayRequireMeshUV
     {

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

 
 namespace UnityEditor.ShaderGraph
 {
-    interface IMayRequireVertexColor
-    {
-        bool RequiresVertexColor();
-    }
-
     [Title("Input", "Geometry", "Vertex Color")]
     public class VertexColorNode : AbstractMaterialNode, IMayRequireVertexColor
     {

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

         {
             properties.Add(new PreviewProperty
             {
-                m_Name = GetVariableNameForSlot(OutputSlotId),
-                m_PropType = PropertyType.Cubemap,
-                m_Cubemap = cubemap
+                name = GetVariableNameForSlot(OutputSlotId),
+                propType = PropertyType.Cubemap,
+                cubemapValue = cubemap
             });
         }
 

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

         {
             properties.Add(new PreviewProperty
             {
-                m_Name = GetVariableNameForSlot(OutputSlotId),
-                m_PropType = PropertyType.Texture,
-                m_Texture = texture
+                name = GetVariableNameForSlot(OutputSlotId),
+                propType = PropertyType.Texture,
+                textureValue = texture
             });
         }
 

MaterialGraphProject/Assets/UnityShaderEditor/Editor/Data/Nodes/Input/Texture/Texture2DNode.cs

 
         public bool RequiresMeshUV(UVChannel channel)
         {
-            foreach (var slot in GetInputSlots<MaterialSlot>().OfType<IMayRequireMeshUV>())
+            s_TempSlots.Clear();
+            GetInputSlots(s_TempSlots);
+            foreach (var slot in s_TempSlots)
             {
                 if (slot.RequiresMeshUV(channel))
                     return true;

MaterialGraphProject/Assets/UnityShaderEditor/Editor/Data/SubGraph/SubGraphNode.cs

             // Step 1...
             // find out which output slots are actually used
             //var validOutputSlots = NodeUtils.GetSlotsThatOutputToNodeRecurse(this, (graph as BaseMaterialGraph).masterNode);
-            foreach (var slot in GetOutputSlots<MaterialSlot>())
+            s_TempSlots.Clear();
+            GetOutputSlots(s_TempSlots);
+            foreach (var slot in s_TempSlots)
             {
                 var outDimension = ConvertConcreteSlotValueTypeToString(precision, slot.concreteValueType);
                 outputString.AddShaderChunk(string.Format("{0} {1} = 0;", outDimension, GetVariableNameForSlot(slot.id)), false);
 
             // Step 5...
             // Copy the outputs to the parent context name);
-            foreach (var slot in GetOutputSlots<MaterialSlot>())
+            s_TempSlots.Clear();
+            GetOutputSlots(s_TempSlots);
+            foreach (var slot in s_TempSlots)
             {
                 var inputValue = subGraphOutputNode.GetSlotValue(slot.id, GenerationMode.ForReals);
 

MaterialGraphProject/Assets/UnityShaderEditor/Editor/Data/SubGraph/SubGraphOutputNode.cs

 
         public virtual int AddSlot()
         {
-            var index = GetInputSlots<ISlot>().Count() + 1;
+            var index = this.GetInputSlots<ISlot>().Count() + 1;
             AddSlot(new Vector4MaterialSlot(index, "Output " + index, "Output" + index, SlotType.Input, Vector4.zero));
             return index;
         }
-            var index = GetInputSlots<ISlot>().Count();
+            var index = this.GetInputSlots<ISlot>().Count();
             if (index == 0)
                 return;
 

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

         }
 
         Stack<Guid> m_Wavefront = new Stack<Guid>();
+        List<IEdge> m_Edges = new List<IEdge>();
+        List<MaterialSlot> m_Slots = new List<MaterialSlot>();
 
         void PropagateNodeSet(HashSet<Guid> nodeGuidSet, bool forward = true, IEnumerable<Guid> initialWavefront = null)
         {
                     continue;
 
                 // Loop through all nodes that the node feeds into.
-                foreach (var slot in forward ? node.GetOutputSlots<ISlot>() : node.GetInputSlots<ISlot>())
+                m_Slots.Clear();
+                if (forward)
+                    node.GetOutputSlots(m_Slots);
+                else
+                    node.GetInputSlots(m_Slots);
+                foreach (var slot in m_Slots)
-                    foreach (var edge in m_Graph.GetEdges(slot.slotReference))
+                    m_Edges.Clear();
+                    m_Graph.GetEdges(slot.slotReference, m_Edges);
+                    foreach (var edge in m_Edges)
                     {
                         // We look at each node we feed into.
                         var connectedSlot = forward ? edge.inputSlot : edge.outputSlot;
                         ShaderUtil.UpdateShaderAsset(m_UberShader, m_UberShaderString);
                         File.WriteAllText(Application.dataPath + "/../UberShader.shader", (m_UberShaderString ?? "null").Replace("UnityEngine.MaterialGraph", "Generated"));
                         var message = "RecreateUberShader: " + Environment.NewLine + m_UberShaderString;
+                        bool uberShaderHasError = false;
+                            uberShaderHasError = true;
                         }
 
                         foreach (var node in uberNodes)
                                 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);
 
                 foreach (var previewProperty in m_PreviewProperties)
                 {
-                    if (previewProperty.m_PropType == PropertyType.Texture && previewProperty.m_Texture != null)
-                        m_PreviewPropertyBlock.SetTexture(previewProperty.m_Name, previewProperty.m_Texture);
-                    else if (previewProperty.m_PropType == PropertyType.Cubemap && previewProperty.m_Cubemap != null)
-                        m_PreviewPropertyBlock.SetTexture(previewProperty.m_Name, previewProperty.m_Cubemap);
-                    else if (previewProperty.m_PropType == PropertyType.Color)
-                        m_PreviewPropertyBlock.SetColor(previewProperty.m_Name, previewProperty.m_Color);
-                    else if (previewProperty.m_PropType == PropertyType.Vector2)
-                        m_PreviewPropertyBlock.SetVector(previewProperty.m_Name, previewProperty.m_Vector4);
-                    else if (previewProperty.m_PropType == PropertyType.Vector3)
-                        m_PreviewPropertyBlock.SetVector(previewProperty.m_Name, previewProperty.m_Vector4);
-                    else if (previewProperty.m_PropType == PropertyType.Vector4)
-                        m_PreviewPropertyBlock.SetVector(previewProperty.m_Name, previewProperty.m_Vector4);
-                    else if (previewProperty.m_PropType == PropertyType.Float)
-                        m_PreviewPropertyBlock.SetFloat(previewProperty.m_Name, previewProperty.m_Float);
+                    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_PreviewProperties.Clear();
             }
                     renderData.texture = null;
                     continue;
                 }
-                if (MaterialGraphAsset.ShaderHasError(renderData.shaderData.shader))
+                if (renderData.shaderData.hasError)
                 {
                     renderData.texture = m_ErrorTexture;
                     continue;
             m_SceneResources.camera.transform.rotation = Quaternion.identity;
             m_SceneResources.camera.orthographicSize = 1;
             m_SceneResources.camera.orthographic = true;
+            m_RenderList2D.Sort((data1, data2) => data1.shaderData.shader.GetInstanceID().CompareTo(data2.shaderData.shader.GetInstanceID()));
-                m_PreviewMaterial.shader = renderData.shaderData.shader;
+                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;
             m_SceneResources.camera.transform.position = -Vector3.forward * 5;
             m_SceneResources.camera.transform.rotation = Quaternion.identity;
             m_SceneResources.camera.orthographic = false;
-            foreach (var previewData in m_RenderList3D)
+            m_RenderList3D.Sort((data1, data2) => data1.shaderData.shader.GetInstanceID().CompareTo(data2.shaderData.shader.GetInstanceID()));
+            foreach (var renderData in m_RenderList3D)
-                if (m_UberShaderIds.TryGetValue(previewData.shaderData.node.guid, out outputId))
+                if (m_UberShaderIds.TryGetValue(renderData.shaderData.node.guid, out outputId))
-                m_PreviewMaterial.shader = previewData.shaderData.shader;
-                m_SceneResources.camera.targetTexture = previewData.renderTexture;
+                if (m_PreviewMaterial.shader != renderData.shaderData.shader)
+                    m_PreviewMaterial.shader = renderData.shaderData.shader;
+                m_SceneResources.camera.targetTexture = renderData.renderTexture;
-                RenderTexture.active = previewData.renderTexture;
+                RenderTexture.active = renderData.renderTexture;
-                Graphics.Blit(Texture2D.whiteTexture, previewData.renderTexture, m_SceneResources.checkerboardMaterial);
-                var mesh = previewData.mesh ?? m_SceneResources.sphere;
+                Graphics.Blit(Texture2D.whiteTexture, renderData.renderTexture, m_SceneResources.checkerboardMaterial);
+                var mesh = renderData.mesh ?? m_SceneResources.sphere;
-                Unsupported.useScriptableRenderPipeline = previewData.shaderData.node is IMasterNode;
+                Unsupported.useScriptableRenderPipeline = renderData.shaderData.node is IMasterNode;
-                previewData.texture = previewData.renderTexture;
+                renderData.texture = renderData.renderTexture;
-            foreach (var previewRenderData in m_RenderList2D.Union(m_RenderList3D))
-            {
-                if (previewRenderData.onPreviewChanged != null)
-                    previewRenderData.onPreviewChanged();
-            }
+            foreach (var renderData in m_RenderList2D)
+                renderData.NotifyPreviewChanged();
+            foreach (var renderData in m_RenderList3D)
+                renderData.NotifyPreviewChanged();
 
             m_RenderList2D.Clear();
             m_RenderList3D.Clear();
             if (string.IsNullOrEmpty(shaderData.shaderString))
             {
                 if (shaderData.shader != null)
+                {
+                    ShaderUtil.ClearShaderErrors(shaderData.shader);
-                shaderData.shader = null;
+                    shaderData.shader = null;
+                }
-            }
-
-            if (shaderData.shader != null && MaterialGraphAsset.ShaderHasError(shaderData.shader))
-            {
-                ShaderUtil.ClearShaderErrors(shaderData.shader);
-                Object.DestroyImmediate(shaderData.shader, true);
-                shaderData.shader = null;
             }
 
             if (shaderData.shader == null)
             // Debug output
             var message = "RecreateShader: " + node.GetVariableNameForNode() + Environment.NewLine + shaderData.shaderString;
             if (MaterialGraphAsset.ShaderHasError(shaderData.shader))
+            {
+                shaderData.hasError = true;
+                ShaderUtil.ClearShaderErrors(shaderData.shader);
+                Object.DestroyImmediate(shaderData.shader, true);
+                shaderData.shader = null;
+            }
+            else
+            {
+                shaderData.hasError = false;
+            }
         }
 
         void DestroyPreview(Guid nodeGuid, PreviewRenderData previewRenderData)
         public Shader shader { get; set; }
         public string shaderString { get; set; }
         public PreviewMode previewMode { get; set; }
+        public bool hasError { get; set; }
     }
 
     public class PreviewRenderData
         public RenderTexture renderTexture { get; set; }
         public Texture texture { get; set; }
         public OnPreviewChanged onPreviewChanged;
+
+        public void NotifyPreviewChanged()
+        {
+            if (onPreviewChanged != null)
+                onPreviewChanged();
+        }
     }
 }

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

 using System.Reflection;
 using UnityEditor.Experimental.UIElements;
 using UnityEditor.Experimental.UIElements.GraphView;
+using UnityEditor.Graphing;
 using UnityEngine;
 using UnityEngine.Experimental.UIElements;
 using INode = UnityEditor.Graphing.INode;
             return true;
         }
 
+        static List<IEdge> s_TempEdges = new List<IEdge>();
+
         bool OnConvertToProperty()
         {
             if (m_GraphView == null)
                 var oldSlot = node.FindSlot<MaterialSlot>(converter.outputSlotId);
                 var newSlot = propNode.FindSlot<MaterialSlot>(PropertyNode.OutputSlotId);
 
-                var edges = m_Graph.GetEdges(oldSlot.slotReference).ToArray();
-                foreach (var edge in edges)
+                s_TempEdges.Clear();
+                m_Graph.GetEdges(oldSlot.slotReference, s_TempEdges);
+                foreach (var edge in s_TempEdges)
                     m_Graph.Connect(newSlot.slotReference, edge.inputSlot);
 
                 m_Graph.RemoveNode(node);

MaterialGraphProject/Assets/UnityShaderEditor/Editor/SerializableGraph/Implementation/Edge.cs

         {
             unchecked
             {
-                return ((m_OutputSlot != null ? m_OutputSlot.GetHashCode() : 0) * 397) ^ (m_InputSlot != null ? m_InputSlot.GetHashCode() : 0);
+                // Can't make fields readonly due to Unity serialization
+                return (m_OutputSlot.GetHashCode() * 397) ^ m_InputSlot.GetHashCode();
             }
         }
     }

MaterialGraphProject/Assets/UnityShaderEditor/Editor/SerializableGraph/Implementation/SerializableGraph.cs

             return new Dictionary<SerializationHelper.TypeSerializationInfo, SerializationHelper.TypeSerializationInfo>();
         }
 
+        static List<IEdge> s_TempEdges = new List<IEdge>();
+
-            if (fromSlotRef == null || toSlotRef == null)
-                return null;
-
             var fromNode = GetNodeFromGuid(fromSlotRef.nodeGuid);
             var toNode = GetNodeFromGuid(toSlotRef.nodeGuid);
 
             var fromSlot = fromNode.FindSlot<ISlot>(fromSlotRef.slotId);
             var toSlot = toNode.FindSlot<ISlot>(toSlotRef.slotId);
 
-            SlotReference outputSlot = null;
-            SlotReference inputSlot = null;
+            if (fromSlot.isOutputSlot == toSlot.isOutputSlot)
+                return null;
-            // output must connect to input
-            if (fromSlot.isOutputSlot)
-                outputSlot = fromSlotRef;
-            else if (fromSlot.isInputSlot)
-                inputSlot = fromSlotRef;
+            var outputSlot = fromSlot.isOutputSlot ? fromSlotRef : toSlotRef;
+            var inputSlot = fromSlot.isInputSlot ? fromSlotRef : toSlotRef;
-            if (toSlot.isOutputSlot)
-                outputSlot = toSlotRef;
-            else if (toSlot.isInputSlot)
-                inputSlot = toSlotRef;
-
-            if (inputSlot == null || outputSlot == null)
-                return null;
-
-            var slotEdges = GetEdges(inputSlot).ToList();
+            s_TempEdges.Clear();
+            GetEdges(inputSlot, s_TempEdges);
-            foreach (var edge in slotEdges)
+            foreach (var edge in s_TempEdges)
             {
                 RemoveEdgeNoValidate(edge);
             }
             return default(T);
         }
 
-        public IEnumerable<IEdge> GetEdges(SlotReference s)
+        public void GetEdges(SlotReference s, List<IEdge> foundEdges)
-            if (s == null)
-                return Enumerable.Empty<IEdge>();
-
-                return Enumerable.Empty<IEdge>();
+                return;
-                return Enumerable.Empty<IEdge>();
+                return;
-            return candidateEdges.Where(candidateEdge =>
-                {
-                    var cs = slot.isInputSlot ? candidateEdge.inputSlot : candidateEdge.outputSlot;
-                    return cs.nodeGuid == s.nodeGuid && cs.slotId == s.slotId;
-                });
+            foreach (var edge in candidateEdges)
+            {
+                var cs = slot.isInputSlot ? edge.inputSlot : edge.outputSlot;
+                if (cs.nodeGuid == s.nodeGuid && cs.slotId == s.slotId)
+                    foundEdges.Add(edge);
+            }
         }
 
         public virtual void OnBeforeSerialize()

MaterialGraphProject/Assets/UnityShaderEditor/Editor/SerializableGraph/Implementation/SerializableNode.cs

 
         public OnNodeModified onModified { get; set; }
 
-        public IEnumerable<T> GetInputSlots<T>() where T : ISlot
+        public void GetInputSlots<T>(List<T> foundSlots) where T : ISlot
-            return GetSlots<T>().Where(x => x.isInputSlot);
+            foreach (var slot in m_Slots)
+            {
+                if (slot.isInputSlot && slot is T)
+                    foundSlots.Add((T)slot);
+            }
-        public IEnumerable<T> GetOutputSlots<T>() where T : ISlot
+        public void GetOutputSlots<T>(List<T> foundSlots) where T : ISlot
-            return GetSlots<T>().Where(x => x.isOutputSlot);
+            foreach (var slot in m_Slots)
+            {
+                if (slot.isOutputSlot && slot is T)
+                    foundSlots.Add((T)slot);
+            }
-        public IEnumerable<T> GetSlots<T>() where T : ISlot
+        public void GetSlots<T>(List<T> foundSlots) where T : ISlot
-            return m_Slots.OfType<T>();
+            foreach (var slot in m_Slots)
+            {
+                if (slot is T)
+                    foundSlots.Add((T)slot);
+            }
         }
 
         public virtual void AddSlot(ISlot slot)
         {
             var slot = FindSlot<ISlot>(slotId);
             if (slot == null)
-                return null;
+                throw new ArgumentException("Slot could not be found", "slotId");
-            return GetSlots<T>().FirstOrDefault(x => x.id == slotId);
+            foreach (var slot in m_Slots)
+            {
+                if (slot.id == slotId && slot is T)
+                    return (T)slot;
+            }
+            return default(T);
-            return GetInputSlots<T>().FirstOrDefault(x => x.id == slotId);
+            foreach (var slot in m_Slots)
+            {
+                if (slot.isInputSlot && slot.id == slotId && slot is T)
+                    return (T)slot;
+            }
+            return default(T);
-            return GetOutputSlots<T>().FirstOrDefault(x => x.id == slotId);
+            foreach (var slot in m_Slots)
+            {
+                if (slot.isOutputSlot && slot.id == slotId && slot is T)
+                    return (T)slot;
+            }
+            return default(T);
-            return GetInputSlots<ISlot>().Where(x => !owner.GetEdges(GetSlotReference(x.id)).Any());
+            return this.GetInputSlots<ISlot>().Where(x => !owner.GetEdges(GetSlotReference(x.id)).Any());
         }
 
         public virtual void OnBeforeSerialize()

MaterialGraphProject/Assets/UnityShaderEditor/Editor/SerializableGraph/Interfaces/IGraph.cs

         INode GetNodeFromGuid(Guid guid);
         bool ContainsNodeGuid(Guid guid);
         T GetNodeFromGuid<T>(Guid guid) where T : INode;
-        IEnumerable<IEdge> GetEdges(SlotReference s);
+        void GetEdges(SlotReference s, List<IEdge> foundEdges);
         void ValidateGraph();
         void ReplaceWith(IGraph other);
         IGraphObject owner { get; set; }
         IEnumerable<IEdge> removedEdges { get; }
         void ClearChanges();
+    }
+
+    public static class GraphExtensions
+    {
+        public static IEnumerable<IEdge> GetEdges(this IGraph graph, SlotReference s)
+        {
+            var edges = new List<IEdge>();
+            graph.GetEdges(s, edges);
+            return edges;
+        }
     }
 }

MaterialGraphProject/Assets/UnityShaderEditor/Editor/SerializableGraph/Interfaces/INode.cs

         Guid RewriteGuid();
         string name { get; set; }
         bool canDeleteNode { get; }
-        IEnumerable<T> GetInputSlots<T>() where T : ISlot;
-        IEnumerable<T> GetOutputSlots<T>() where T : ISlot;
-        IEnumerable<T> GetSlots<T>() where T : ISlot;
+        void GetInputSlots<T>(List<T> foundSlots) where T : ISlot;
+        void GetOutputSlots<T>(List<T> foundSlots) where T : ISlot;
+        void GetSlots<T>(List<T> foundSlots) where T : ISlot;
         void AddSlot(ISlot slot);
         void RemoveSlot(int slotId);
         SlotReference GetSlotReference(int slotId);
         bool hasError { get; }
         void ValidateNode();
         void UpdateNodeAfterDeserialization();
+    }
+
+    public static class NodeExtensions
+    {
+        public static IEnumerable<T> GetSlots<T>(this INode node) where T : ISlot
+        {
+            var slots = new List<T>();
+            node.GetSlots(slots);
+            return slots;
+        }
+
+        public static IEnumerable<T> GetInputSlots<T>(this INode node) where T : ISlot
+        {
+            var slots = new List<T>();
+            node.GetInputSlots(slots);
+            return slots;
+        }
+
+        public static IEnumerable<T> GetOutputSlots<T>(this INode node) where T : ISlot
+        {
+            var slots = new List<T>();
+            node.GetOutputSlots(slots);
+            return slots;
+        }
     }
 }

MaterialGraphProject/Assets/UnityShaderEditor/Editor/SerializableGraph/Interfaces/SlotReference.cs

 namespace UnityEditor.Graphing
 {
     [Serializable]
-    public class SlotReference : ISerializationCallbackReceiver, IEquatable<SlotReference>
+    public struct SlotReference : ISerializationCallbackReceiver, IEquatable<SlotReference>
     {
         [SerializeField]
         private int m_SlotId;

MaterialGraphProject/Assets/UnityShaderEditor/Editor/SerializableGraph/Testing/UnitTests/SerializedGraphTests.cs

 
             Assert.AreEqual(2, graph.GetNodes<INode>().Count());
 
-            var createdEdge = graph.Connect(outputNode.GetSlotReference(TestableNode.Output0), null);
-            Assert.AreEqual(0, graph.edges.Count());
-            Assert.IsNull(createdEdge);
-
             var createdEdge2 = graph.Connect(outputNode.GetSlotReference(TestableNode.Output0), new SlotReference(Guid.NewGuid(), 666));
             Assert.AreEqual(0, graph.edges.Count());
             Assert.IsNull(createdEdge2);

MaterialGraphProject/Assets/UnityShaderEditor/Editor/Testing/UnitTests/MaterialNodeTests.cs

             Assert.AreEqual(1, properties.Count);
             var pp = properties.FirstOrDefault();
 
-            Assert.AreEqual(m_NodeA.GetVariableNameForSlot(slot.id), pp.m_Name);
-            Assert.AreEqual(PropertyType.Float, pp.m_PropType);
-            Assert.AreEqual(slot.value, pp.m_Vector4);
+            Assert.AreEqual(m_NodeA.GetVariableNameForSlot(slot.id), pp.name);
+            Assert.AreEqual(PropertyType.Float, pp.propType);
+            Assert.AreEqual(slot.value, pp.vector4Value);
         }
 
         [Test]

MaterialGraphProject/Assets/UnityShaderEditor/Editor/Data/Interfaces/IMayRequireMeshUV.cs

+using UnityEditor.Graphing;
+
+namespace UnityEditor.ShaderGraph
+{
+    public interface IMayRequireMeshUV
+    {
+        bool RequiresMeshUV(UVChannel channel);
+    }
+
+    public static class MayRequireMeshUVExtensions
+    {
+        public static bool RequiresMeshUV(this ISlot slot, UVChannel channel)
+        {
+            var mayRequireMeshUV = slot as IMayRequireMeshUV;
+            return mayRequireMeshUV != null && mayRequireMeshUV.RequiresMeshUV(channel);
+        }
+    }
+}

MaterialGraphProject/Assets/UnityShaderEditor/Editor/Data/Interfaces/IMayRequireMeshUV.cs.meta

+fileFormatVersion: 2
+guid: c23e123c3ff140c997d68b663b484f29
+timeCreated: 1512469718

MaterialGraphProject/Assets/UnityShaderEditor/Editor/Data/Interfaces/IMayRequireScreenPosition.cs

+using UnityEditor.Graphing;
+
+namespace UnityEditor.ShaderGraph
+{
+    public interface IMayRequireScreenPosition
+    {
+        bool RequiresScreenPosition();
+    }
+
+    public static class MayRequireScreenPositionExtensions
+    {
+        public static bool RequiresScreenPosition(this ISlot slot)
+        {
+            var mayRequireScreenPosition = slot as IMayRequireScreenPosition;
+            return mayRequireScreenPosition != null && mayRequireScreenPosition.RequiresScreenPosition();
+        }
+    }
+}

MaterialGraphProject/Assets/UnityShaderEditor/Editor/Data/Interfaces/IMayRequireScreenPosition.cs.meta

+fileFormatVersion: 2
+guid: f7223ad4b07146cc98966aad000f017d
+timeCreated: 1512469767

MaterialGraphProject/Assets/UnityShaderEditor/Editor/Data/Interfaces/IMayRequireVertexColor.cs

+using UnityEditor.Graphing;
+
+namespace UnityEditor.ShaderGraph
+{
+    interface IMayRequireVertexColor
+    {
+        bool RequiresVertexColor();
+    }
+
+    public static class MayRequireVertexColorExtensions
+    {
+        public static bool RequiresVertexColor(this ISlot slot)
+        {
+            var mayRequireVertexColor = slot as IMayRequireVertexColor;
+            return mayRequireVertexColor != null && mayRequireVertexColor.RequiresVertexColor();
+        }
+    }
+}

MaterialGraphProject/Assets/UnityShaderEditor/Editor/Data/Interfaces/IMayRequireVertexColor.cs.meta

+fileFormatVersion: 2
+guid: 04d654703054418c8db537b52ae070dc
+timeCreated: 1512469863

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

-fileFormatVersion: 2
-guid: 73ed72480b864b078821956f4f00da99
-timeCreated: 1503563173

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

-using UnityEditor.Graphing;
-
-namespace UnityEditor.ShaderGraph
-{
-    public static class MaterialNodeExtensions
-    {
-        public static bool RequiresTime(this INode node)
-        {
-            var timeNode = node as IMayRequireTime;
-            return timeNode != null && timeNode.RequiresTime();
-        }
-    }
-}