Add world tangent node (with IRequireTangent behavior)

MaterialGraphProject/Assets/UnityShaderEditor/Runtime/Nodes/AbstractSurfaceMasterNode.cs

                 shaderBody.AddShaderChunk("float4 " + ShaderGeneratorNames.ScreenPosition + " = IN.screenPos;", true);
             }
 
+            if (activeNodeList.OfType<IMayRequireTangent>().Any(x => x.RequiresTangent()))
+            {
+                shaderInputVisitor.AddShaderChunk("float3 worldTangent;", true);
+                vertexShaderBlock.AddShaderChunk("o.worldTangent = UnityObjectToWorldDir(v.tangent.xyz);", true);
+                shaderBody.AddShaderChunk("float3 " + ShaderGeneratorNames.WorldSpaceTangent + " = normalize(IN.worldTangent);", true);
+            }
+
             if (activeNodeList.OfType<IMayRequireNormal>().Any(x => x.RequiresNormal()))
             {
                 // is the normal connected?

MaterialGraphProject/Assets/UnityShaderEditor/Runtime/SubGraph/SubGraphNode.cs

         , IGeneratesFunction
         , IOnAssetEnabled
         , IMayRequireNormal
+        , IMayRequireTangent
         , IMayRequireMeshUV
         , IMayRequireScreenPosition
         , IMayRequireViewDirection
                 return false;
 
             return subGraph.activeNodes.OfType<IMayRequireWorldPosition>().Any(x => x.RequiresWorldPosition());
+        }
+
+        public bool RequiresTangent()
+        {
+            if (subGraph == null)
+                return false;
+
+            return subGraph.activeNodes.OfType<IMayRequireTangent>().Any(x => x.RequiresTangent());
         }
     }
 }

MaterialGraphProject/Assets/UnityShaderEditor/Runtime/Util/ShaderGenerator.cs

     public static class ShaderGeneratorNames
     {
         public const string WorldSpaceNormal = "worldSpaceNormal";
+        public const string WorldSpaceTangent = "worldSpaceTangent";
         public const string WorldSpacePosition = "worldPosition";
         public const string WorldSpaceViewDirection = "worldSpaceViewDirection";
         public const string ScreenPosition = "screenPosition";
                 shaderInputVisitor.AddShaderChunk("float4 screenPos : TEXCOORD3;", true);
                 vertexShaderBlock.AddShaderChunk("o.screenPos = screenPos;", true);
                 shaderBodyVisitor.AddShaderChunk("half4 " + ShaderGeneratorNames.ScreenPosition + " = IN.screenPos;", true);
+            }
+
+            if (activeNodeList.OfType<IMayRequireTangent>().Any(x => x.RequiresTangent()))
+            {
+                shaderInputVisitor.AddShaderChunk("float3 worldTangent : TEXCOORD4;", true);
+                vertexShaderBlock.AddShaderChunk("o.worldTangent = UnityObjectToWorldDir(v.tangent.xyz);", true);
+                shaderBodyVisitor.AddShaderChunk("float3 " + ShaderGeneratorNames.WorldSpaceTangent + " = normalize(IN.worldTangent);", true);
             }
 
             var generationMode = GenerationMode.Preview;

MaterialGraphProject/Assets/UnityShaderEditor/Runtime/Nodes/WorldSpaceTangentNode.cs

+using UnityEngine.Graphing;
+
+namespace UnityEngine.MaterialGraph
+{
+    public interface IMayRequireTangent
+    {
+        bool RequiresTangent();
+    }
+
+    [Title("Input/World Tangent Node")]
+    public class WorldSpaceTangentNode : AbstractMaterialNode, IMayRequireTangent
+    {
+        public const int kOutputSlotId = 0;
+        public const string kOutputSlotName = "Tangent";
+
+        public WorldSpaceTangentNode()
+        {
+            name = "World Tangent";
+            UpdateNodeAfterDeserialization();
+        }
+
+        public sealed override void UpdateNodeAfterDeserialization()
+        {
+            AddSlot(new MaterialSlot(kOutputSlotId, kOutputSlotName, kOutputSlotName, SlotType.Output, SlotValueType.Vector3, new Vector4(0, 0, 1, 1)));
+            RemoveSlotsNameNotMatching(new[] { kOutputSlotId });
+        }
+
+        public override bool hasPreview
+        {
+            get { return true; }
+        }
+
+        public override PreviewMode previewMode
+        {
+            get { return PreviewMode.Preview3D; }
+        }
+
+        public override string GetVariableNameForSlot(int slotId)
+        {
+            return ShaderGeneratorNames.WorldSpaceTangent;
+        }
+
+        public bool RequiresTangent()
+        {
+            return true;
+        }
+    }
+}

MaterialGraphProject/Assets/UnityShaderEditor/Runtime/Nodes/WorldSpaceTangentNode.cs.meta

+fileFormatVersion: 2
+guid: 9e8bd6ff1eba8ea4589ec534a00f4767
+timeCreated: 1480080968
+licenseType: Pro
+MonoImporter:
+  serializedVersion: 2
+  defaultReferences: []
+  executionOrder: 0
+  icon: {instanceID: 0}
+  userData: 
+  assetBundleName: 
+  assetBundleVariant: