Added checkbox for enabling Tile Debug Visualization

Assets/ScriptableRenderLoop/fptl/FptlLighting.cs

         // clustered light list specific buffers and data begin
         public bool enableClustered = false;
         public bool enableDrawLightBoundsDebug = false;
+        public bool enableDrawTileDebug = false;
         const bool k_UseDepthBuffer = true;//      // only has an impact when EnableClustered is true (requires a depth-prepass)
         const bool disableFptlWhenClustered = false;    // still useful on opaques
         const int k_Log2NumClusters = 6;     // accepted range is from 0 to 6. NumClusters is 1<<g_iLog2NumClusters
 
             m_DeferredMaterial.EnableKeyword(bUseClusteredForDeferred ? "USE_CLUSTERED_LIGHTLIST" : "USE_FPTL_LIGHTLIST");
             m_DeferredReflectionMaterial.EnableKeyword(bUseClusteredForDeferred ? "USE_CLUSTERED_LIGHTLIST" : "USE_FPTL_LIGHTLIST");
+            if (enableDrawTileDebug)
+                m_DeferredMaterial.EnableKeyword("ENABLE_DEBUG");
+            else
+                m_DeferredMaterial.DisableKeyword("ENABLE_DEBUG");
 
             cmd.SetGlobalBuffer("g_vLightListGlobal", bUseClusteredForDeferred ? s_PerVoxelLightLists : s_LightList);       // opaques list (unless MSAA possibly)
 

Assets/ScriptableRenderLoop/fptl/Internal-DeferredShading.shader

 #pragma fragment frag
 
 #pragma multi_compile USE_FPTL_LIGHTLIST    USE_CLUSTERED_LIGHTLIST
+#pragma multi_compile __ ENABLE_DEBUG
 
 #include "UnityLightingCommon.cginc"
 
     uint numLightsProcessed = 0;
     float3 c = data.emission + ExecuteLightList(numLightsProcessed, pixCoord, vP, vPw, Vworld);
 
-    //c = OverlayHeatMap(pixCoord & 15, numLightsProcessed, c);
+#if ENABLE_DEBUG
+    c = OverlayHeatMap(pixCoord & 15, numLightsProcessed, c);
+#endif
     return float4(c,1.0);
 }