Implement Emmanuel's energy compensation method

ScriptableRenderPipeline/HDRenderPipeline/Material/Lit/Lit.hlsl

     }
     specularLighting += F * DV;
 
-#define MS_GGX 1
+#define MS_GGX            1
+#define MS_GGX_IMAGEWORKS 0
+#if MS_GGX_IMAGEWORKS
-#endif
+#else
+    float ecV = SAMPLE_TEXTURE2D_LOD(_GgxEnergyCompensationFactors, s_linear_clamp_sampler, float2(NdotV, bsdfData.perceptualRoughness), 0).r;
+    specularLighting += F * DV * ecV;
+#endif // MS_GGX_IMAGEWORKS
+#endif // MS_GGX
 
 #ifdef LIT_DIFFUSE_LAMBERT_BRDF
     float  diffuseTerm = Lambert();

ScriptableRenderPipeline/HDRenderPipeline/Material/Lit/Resources/ComputeGgxEnergyCompensationFactors.shader

                 float3 V         = float3(sqrt(1 - NdotV * NdotV), 0, NdotV);
 
                 float fDir = ComputeGgxEnergyCompensationFactor(V, N, roughness);
+
+            #define MS_GGX_IMAGEWORKS 0
+
+            #if MS_GGX_IMAGEWORKS
                 float fAvg = 0;
 
                 const uint numSamples = 128;
                     fAvg += ComputeGgxEnergyCompensationFactor(V, N, roughness) * NdotV * (2 * rcp(numSamples));
                 }
 
+                // f_ms = f[NdotV, perceptualRoughness] * f[NdotL, perceptualRoughness].
+            #else
+                // f_ms = f[NdotV, perceptualRoughness] * f_ss.
+                float f = 1 / fDir - 1;
+            #endif
-                // f_ms = f[NdotV, perceptualRoughness] * f[NdotL, perceptualRoughness].
                 return f.xxxx;
             }