Add everything to vertex input struct as default

MaterialGraphProject/Assets/SRP/ScriptableRenderPipeline/LightweightPipeline/Shaders/MetallicTest.ShaderGraph.meta

 fileFormatVersion: 2
 guid: 02a3ca69ec995e94aa47105621a17e4c
-timeCreated: 1505499381
+timeCreated: 1505501440
 licenseType: Pro
 ShaderImporter:
   externalObjects: {}

MaterialGraphProject/Assets/UnityShaderEditor/Runtime/LightweightPipeline/AbstractLightweightPBRMasterNode.cs

                 node.GeneratePropertyUsages(propertyUsages, mode);
             }
 
-            int vertInputIndex = 1;
-            // Need these for lighting
+            // always add everything because why not. 
-            shaderInputVisitor.AddShaderChunk("float4 normal : NORMAL;", true);
-            shaderInputVisitor.AddShaderChunk("float2 lightmapUV : TEXCOORD0;", true);
-            // always add color because why not. 
-            shaderInputVisitor.AddShaderChunk("float4 color : COLOR;", true);
+            shaderInputVisitor.AddShaderChunk("half3 normal : NORMAL;", true);
+            shaderInputVisitor.AddShaderChunk("half4 texcoord0 : TEXCOORD0;", true);
+            shaderInputVisitor.AddShaderChunk("float2 lightmapUV : TEXCOORD1;", true);
+            shaderInputVisitor.AddShaderChunk("half4 tangent : TEXCOORD2;", true);
+            shaderInputVisitor.AddShaderChunk("half4 color : COLOR;", true);
 
             // Need these for lighting
             shaderOutputVisitor.AddShaderChunk("float4 posWS : TEXCOORD0;", true);
                 var channel = (UVChannel)uvIndex;
                 if (activeNodeList.OfType<IMayRequireMeshUV>().Any(x => x.RequiresMeshUV(channel)))
                 {
-                    shaderInputVisitor.AddShaderChunk(string.Format("half4 texcoord{0} : TEXCOORD{1};", uvIndex, vertInputIndex), true);
+                    if(uvIndex != 0)
+                    {
+                        shaderInputVisitor.AddShaderChunk(string.Format("half4 texcoord{0} : TEXCOORD{1};", uvIndex, vertInputIndex), true);
+                        vertInputIndex++;
+                    }
-                    vertInputIndex++;
                     vertOutputIndex++;
                 }
             }
 
             if (requiresScreenPosition)
             {
-                shaderInputVisitor.AddShaderChunk(string.Format("half4 screenPos : TEXCOORD{0};", vertInputIndex), true);
-                vertexShaderBlock.AddShaderChunk("o.screenPos = v.screenPos;", true);
+                vertexShaderBlock.AddShaderChunk("o.screenPos = ComputeScreenPos(v.vertex);", true);
-                vertInputIndex++;
-                shaderInputVisitor.AddShaderChunk(string.Format("half4 tangent : TEXCOORD{0};", vertInputIndex), true);
-                vertInputIndex++;
                 vertOutputIndex++;
             }