Fix up setting preview properties to be pull based instead of push based (needs close review)

UnityProject/Assets/UnityShaderEditor/Editor/Source/Editors/BaseMaterialNodeEditor.cs

                 slot.title = EditorGUILayout.TextField("Title", slot.title);
 
             var def = node.GetSlotDefaultValue(slot.name);
-            if (def != null)
+            if (def != null && def.OnGUI())
-                if (def.OnGUI())
-                {
-                    node.UpdatePreviewProperties();
-                }
+                node.UpdatePreviewProperties();
+                node.ForwardPreviewMaterialPropertyUpdate();
             }
         }
 

UnityProject/Assets/UnityShaderEditor/Editor/Source/Nodes/BaseMaterialNode.cs

         private const int kPreviewWidth = 64;
         private const int kPreviewHeight = 64;
 
+        [NonSerialized]
         private UnityEngine.Material m_Material;
 
         [SerializeField]
                 {
                     m_Material = new UnityEngine.Material(defaultPreviewShader) {hideFlags = HideFlags.DontSave};
                     UpdatePreviewMaterial();
+                    UpdatePreviewProperties();
                 }
 
                 return m_Material;
             }
         }
 
-        protected void SetDependentPreviewMaterialProperty(PreviewProperty previewProperty)
+        public void ForwardPreviewMaterialPropertyUpdate()
         {
             var dependentNodes = CollectDependentNodes();
 
-                    node.SetPreviewMaterialProperty(previewProperty);
+                    node.UpdatePreviewProperties();
-        public virtual void UpdatePreviewProperties()
+        protected virtual void CollectPreviewMaterialProperties (List<PreviewProperty> properties)
         {
             foreach (var s in inputSlots)
             {
                     m_PropType = PropertyType.Vector4,
                     m_Vector4 = defaultInput.defaultValue
                 };
-                SetDependentPreviewMaterialProperty(pp);
+                properties.Add (pp);
+        }
+
+        public void UpdatePreviewProperties()
+        {
+            var childrenNodes = CollectChildNodesByExecutionOrder();
+            var pList = new List<PreviewProperty>();
+            foreach (var node in childrenNodes)
+                node.CollectPreviewMaterialProperties(pList);
+
+            foreach (var prop in pList)
+                SetPreviewMaterialProperty (prop);
         }
 
         #endregion

UnityProject/Assets/UnityShaderEditor/Editor/Source/Nodes/ColorNode.cs

                     boundProp.defaultColor = m_Color;
                 }
                 UpdatePreviewProperties();
+                ForwardPreviewMaterialPropertyUpdate();
             }
         }
 
             if (rebuildShaders)
                 RegeneratePreviewShaders();
             else
+            {
+                ForwardPreviewMaterialPropertyUpdate();
+            }
         }
 
         public override PreviewProperty GetPreviewProperty()

UnityProject/Assets/UnityShaderEditor/Editor/Source/Nodes/PropertyNode.cs

 
         public abstract PreviewProperty GetPreviewProperty();
 
-        public override void UpdatePreviewProperties()
+        protected override void CollectPreviewMaterialProperties (List<PreviewProperty> properties)
-            base.UpdatePreviewProperties();
-            MaterialWindow.DebugMaterialGraph("In Property Node: " + this);
-            SetDependentPreviewMaterialProperty(GetPreviewProperty());
+            base.CollectPreviewMaterialProperties(properties);
+            properties.Add(GetPreviewProperty());
         }
 
         public void UnbindProperty(ShaderProperty prop)

UnityProject/Assets/UnityShaderEditor/Editor/Source/Nodes/SubGraphInputsNode.cs

 using UnityEngine;
+using System.Collections.Generic;
 
 namespace UnityEditor.Graphs.Material
 {
             }
         }
 
-        public override void UpdatePreviewProperties()
+        protected override void CollectPreviewMaterialProperties (List<PreviewProperty> properties)
-            base.UpdatePreviewProperties();
+            base.CollectPreviewMaterialProperties(properties);
             foreach (var slot in outputSlots)
             {
                 if (slot.edges.Count == 0)
                     m_PropType = PropertyType.Vector4,
                     m_Vector4 = defaultOutput.defaultValue
                 };
-                SetDependentPreviewMaterialProperty(pp);
+                properties.Add (pp);
             }
         }
     }

UnityProject/Assets/UnityShaderEditor/Editor/Source/Nodes/SubGraphNode.cs

             m_SubGraphAsset.GeneratePropertyUsages(visitor, GenerationMode.SurfaceShader);
         }
 
-        public override void UpdatePreviewProperties()
+        protected override void CollectPreviewMaterialProperties (List<PreviewProperty> properties)
-            base.UpdatePreviewProperties();
-
-            var previewProperties = m_SubGraphAsset.GetPreviewProperties();
-
-            foreach (var prop in previewProperties)
-                SetDependentPreviewMaterialProperty(prop);
+            base.CollectPreviewMaterialProperties(properties);
+            properties.AddRange(m_SubGraphAsset.GetPreviewProperties());
         }
     }
 }

UnityProject/Assets/UnityShaderEditor/Editor/Source/Nodes/TextureNode.cs

                     boundProp.defaultTextureType = m_TextureType;
                 }
                 UpdatePreviewProperties();
+                ForwardPreviewMaterialPropertyUpdate();
             }
         }
 
             if (rebuildShaders)
                 RegeneratePreviewShaders();
             else
+            {
+                ForwardPreviewMaterialPropertyUpdate();
+            }
         }
 
         public override PreviewProperty GetPreviewProperty()

UnityProject/Assets/UnityShaderEditor/Editor/Source/Nodes/Vector4Node.cs

                     boundProp.defaultVector = m_Value;
                 }
                 UpdatePreviewProperties();
+                ForwardPreviewMaterialPropertyUpdate();
             }
         }
 
             if (rebuildShaders)
                 RegeneratePreviewShaders();
             else
+            {
+                ForwardPreviewMaterialPropertyUpdate();
+            }
         }
 
         public override PreviewProperty GetPreviewProperty()

UnityProject/Assets/UnityShaderEditor/Graphs/GlowMud.ShaderGraph

     m_ToSlotName: Input0
     color: {r: 1, g: 1, b: 1, a: 1}
   - m_FromNode: {fileID: 11468266}
-    m_ToNode: {fileID: 11445316}
-    m_FromSlotName: Output
-    m_ToSlotName: UV
-    color: {r: 1, g: 1, b: 1, a: 1}
-  - m_FromNode: {fileID: 11468266}
     m_ToNode: {fileID: 11472310}
     m_FromSlotName: Output
     m_ToSlotName: UV
     m_FromSlotName: Output
     m_ToSlotName: Input1
     color: {r: 1, g: 1, b: 1, a: 1}
+  - m_FromNode: {fileID: 11468266}
+    m_ToNode: {fileID: 11445316}
+    m_FromSlotName: Output
+    m_ToSlotName: UV
+    color: {r: 1, g: 1, b: 1, a: 1}
   m_InvalidEdges: []
 --- !u!114 &11445316
 MonoBehaviour:
   position:
     serializedVersion: 2
     x: 240
-    y: -300
+    y: -312
     width: 213
     height: 139
   showEmptySlots: 1
     m_Node: {fileID: 11445316}
   m_PrecisionNames:
   - half
-  m_BoundProperty: {fileID: 0}
-  m_DefaultTexture: {fileID: 2800000, guid: 330f42016073a97418a4aae5517e32c8, type: 3}
+  m_BoundProperty: {fileID: 11475776}
+  m_DefaultTexture: {fileID: 2800000, guid: 28bdf1ba8c076ef4e910b59cc1baf342, type: 3}
   m_TextureType: 0
 --- !u!114 &11445996
 MonoBehaviour:
   m_BoundProperty: {fileID: 0}
   m_DefaultTexture: {fileID: 2800000, guid: d5649239aacf54d4e8d6f656d15d30b0, type: 3}
   m_TextureType: 3
+--- !u!114 &11475776
+MonoBehaviour:
+  m_ObjectHideFlags: 1
+  m_PrefabParentObject: {fileID: 0}
+  m_PrefabInternal: {fileID: 0}
+  m_GameObject: {fileID: 0}
+  m_Enabled: 1
+  m_EditorHideFlags: 0
+  m_Script: {fileID: 11500000, guid: b793ff9211c8787428ec61378a5b39ac, type: 3}
+  m_Name: TextureProperty
+  m_EditorClassIdentifier: 
+  m_PropertyDescription: 
+  m_DefaultTexture: {fileID: 2800000, guid: 28bdf1ba8c076ef4e910b59cc1baf342, type: 3}
+  m_DefaultTextureType: 0
 --- !u!114 &11477068
 MonoBehaviour:
   m_ObjectHideFlags: 1
   m_Script: {fileID: 11500000, guid: cab057dbd683f5244aed9bd721e1973e, type: 3}
   m_Name: 
   m_EditorClassIdentifier: 
-  m_ShaderProperties: []
+  m_ShaderProperties:
+  - {fileID: 11475776}
   previewState: 0
 --- !u!114 &11480530
 MonoBehaviour: