[ShaderGraph][2021.2][Backport] Ensure blackboard ordering of subgraph properties on subgraph node

com.unity.shadergraph/CHANGELOG.md

@@ -134,6 +134,7 @@ and this project adheres to [Semantic Versioning](http://semver.org/spec/v2.0.0.
 - Fixed a serialization bug wrt PVT property flags when using subgraphs. This fixes SRP batcher compatibility.
 - Fixed an incorrect direction transform from view to world space [1365186]
 - Fixed the appearance (wrong text color, and not wrapped) of a warning in Node Settings [1365780]
+- Fixed the ordering of inputs on a SubGraph node to match the properties on the blackboard of the subgraph itself [1366052]
 
 ## [11.0.0] - 2020-10-21
 

com.unity.shadergraph/Editor/Importers/ShaderSubGraphImporter.cs

@@ -19,7 +19,7 @@
 namespace UnityEditor.ShaderGraph
 {
     [ExcludeFromPreset]
-    [ScriptedImporter(28, Extension, -905)]
+    [ScriptedImporter(29, Extension, -905)]
     class ShaderSubGraphImporter : ScriptedImporter
     {
         public const string Extension = "shadersubgraph";
@@ -281,6 +281,24 @@ static void ProcessSubGraph(SubGraphAsset asset, GraphData graph, ShaderGraphImp
                 }
             }
 
+            // Need to order the properties so that they are in the same order on a subgraph node in a shadergraph
+            // as they are in the blackboard for the subgraph itself.  The (blackboard) categories keep that ordering,
+            // so traverse those and add those items to the ordered properties list.  Needs to be used to set up the
+            // function _and_ to write out the final asset data so that the function call parameter order matches as well.
+            var orderedProperties = new List<AbstractShaderProperty>();
+            var propertiesList = graph.properties.ToList();
+            foreach (var category in graph.categories)
+            {
+                foreach (var child in category.Children)
+                {
+                    var prop = propertiesList.Find(p => p.guid == child.guid);
+                    orderedProperties.Add(prop);
+                }
+            }
+
+            // If we are importing an older file that has not had categories generated for it yet, include those now.
+            orderedProperties.AddRange(graph.properties.Except(orderedProperties));
+
             // provide top level subgraph function
             // NOTE: actual concrete precision here shouldn't matter, it's irrelevant when building the subgraph asset
             registry.ProvideFunction(asset.functionName, asset.subGraphGraphPrecision, ConcretePrecision.Single, sb =>
@@ -290,7 +308,7 @@ static void ProcessSubGraph(SubGraphAsset asset, GraphData graph, ShaderGraphImp
 
                 // Generate the arguments... first INPUTS
                 var arguments = new List<string>();
-                foreach (var prop in graph.properties)
+                foreach (var prop in orderedProperties)
                 {
                     // apply fallback to the graph default precision (but don't convert to concrete)
                     // this means "graph switchable" properties will use the precision token
@@ -388,7 +406,8 @@ static void ProcessSubGraph(SubGraphAsset asset, GraphData graph, ShaderGraphImp
                     prop.OverrideGuid(namespaceId, nameId + "_Guid_" + i);
                 }
             }
-            asset.WriteData(graph.properties, graph.keywords, graph.dropdowns, collector.properties, outputSlots, graph.unsupportedTargets);
+
+            asset.WriteData(orderedProperties, graph.keywords, graph.dropdowns, collector.properties, outputSlots, graph.unsupportedTargets);
             outputSlots.Dispose();
         }