Added LightweightKeywords and ShaderPreprocessor. Stripping Meta pass from build.

ScriptableRenderPipeline/LightweightPipeline/LWRP/Editor/ShaderPreprocessor.cs

+using System.Collections.Generic;
+using UnityEditor.Build;
+using UnityEditor.Rendering;
+using UnityEngine;
+using UnityEngine.Experimental.Rendering.LightweightPipeline;
+using UnityEngine.Rendering;
+
+namespace UnityEditor.Experimental.Rendering.LightweightPipeline
+{
+    class ShaderPreprocessor : IPreprocessShaders
+    {
+        int totalVariantsInputCount = 0;
+        int totalVariantsOutputCount = 0;
+
+        // Multiple callback may be implemented.
+        // The first one executed is the one where callbackOrder is returning the smallest number.
+        public int callbackOrder { get { return 0; } }
+
+        private bool StripUnusedVariant(ShaderSnippetData snippetData, ShaderCompilerData compilerData)
+        {
+            if (snippetData.passName == "Meta")
+                return true;
+
+            return false;
+        }
+
+        public void OnProcessShader(Shader shader, ShaderSnippetData snippet, IList<ShaderCompilerData> data)
+        {
+           int initDataCount = data.Count;
+
+            for (int i = 0; i < data.Count; ++i)
+            {
+                if (StripUnusedVariant(snippet, data[i]))
+                {
+                    data.RemoveAt(i);
+                    --i;
+                }
+            }
+
+            totalVariantsInputCount += initDataCount;
+            totalVariantsOutputCount += data.Count;
+
+            if (shader.name.Contains("LightweightPipeline/Standard (Physically Based)") || shader.name.Contains("LightweightPipeline/Standard (Simple Lighting)"))
+            {
+                float percentageCurrent = (float) data.Count / (float) initDataCount * 100f;
+                float percentageTotal = (float) totalVariantsOutputCount / (float) totalVariantsInputCount * 100f;
+                string result = "STRIPPING: " + shader.name + "(" + snippet.passName + " pass)" + "(" + snippet.shaderType.ToString() +
+                                ") - Remaining shader variants = " + data.Count + " / " + initDataCount + " = " +
+                                percentageCurrent + "% - Total = " + totalVariantsOutputCount + " / " +
+                                totalVariantsInputCount + " = " + percentageTotal + "%";
+                Debug.Log(result);
+            }
+        }
+    }
+}
+

ScriptableRenderPipeline/LightweightPipeline/LWRP/Editor/ShaderPreprocessor.cs.meta

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ScriptableRenderPipeline/LightweightPipeline/LWRP/LightweightKeywords.cs

+using UnityEngine.Rendering;
+
+namespace UnityEngine.Experimental.Rendering.LightweightPipeline
+{
+    public class LightweightKeywords : MonoBehaviour
+    {
+        // Pipeline specific keywords
+        public static readonly ShaderKeyword AdditionalLights = new ShaderKeyword("_ADDITIONAL_LIGHTS");
+        public static readonly ShaderKeyword VertexLights = new ShaderKeyword("_VERTEX_LIGHTS");
+        public static readonly ShaderKeyword SubtractiveLight = new ShaderKeyword("_MIXED_LIGHTING_SUBTRACTIVE");
+        public static readonly ShaderKeyword DirectionalShadows = new ShaderKeyword("_SHADOWS_ENABLED");
+        public static readonly ShaderKeyword LocalShadows = new ShaderKeyword("_LOCAL_SHADOWS_ENABLED");
+
+        public static readonly ShaderKeyword Lightmap = new ShaderKeyword("DIRLIGHTMAP_COMBINED");
+        public static readonly ShaderKeyword DirectionalLightmap = new ShaderKeyword("LIGHTMAP_ON");
+    }
+}
+

ScriptableRenderPipeline/LightweightPipeline/LWRP/LightweightKeywords.cs.meta

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