Add energy compensation term; rough metals look right under direct lighting now

1 files changed, 4 insertions, 6 deletions

diff --git a/brdf.cginc b/brdf.cginc
index d73bde8..ee1a219 100755
--- a/brdf.cginc
+++ b/brdf.cginc
@@ -93,6 +93,8 @@ float4 brdf(Pbr pbr, LightData data) {
   } else {
     dfg = float3(1, 1, 1);
   }
+  float3 f0_color = lerp(f0, pbr.albedo.xyz, pbr.metallic);
+  float3 energy_comp = 1.0f + f0_color * (1.0f / dfg.xxx - 1.0f);
 
 #if defined(_CLEARCOAT)
   const float cc_f0 = 0.04f;
@@ -105,14 +107,9 @@ float4 brdf(Pbr pbr, LightData data) {
     cc_dfg = float3(1, 1, 1);
   }
   float cc_Ess = max(cc_dfg.y, 1e-4f);
-  //float cc_energy_comp = 1.0f + cc_f0 * (rcp(cc_Ess) - 1.0f);
-  float cc_energy_comp = 1;
+  float cc_energy_comp = 1.0f + cc_f0 * (1.0f / cc_dfg.xxx - 1.0f);
 #endif
 
-  float3 f0_color = lerp(f0, pbr.albedo.xyz, pbr.metallic);
-  //float3 energy_comp = 1.0f + f0_color * (rcp(dfg.yyy) - 1.0f);
-  float3 energy_comp = 1.0f;
-
   // Direct
   {
     float3 remainder = 1.0f;
@@ -158,6 +155,7 @@ float4 brdf(Pbr pbr, LightData data) {
     float3 specular_dfg = dfg.xxx * f0_color + dfg.yyy;  // filament 5.3.4.6
     float3 indirect_specular = data.indirect.specular * specular_dfg;
 
+    indirect_specular *= energy_comp;
     specular += indirect_specular;
 
     float3 indirect_diffuse = pbr.albedo.xyz * data.indirect.diffuse * (1.0 - pbr.metallic);