Update specular occlusion; always runs now

1 files changed, 12 insertions, 20 deletions

diff --git a/lighting.cginc b/lighting.cginc
index 9ea2052..2e3a79b 100755
--- a/lighting.cginc
+++ b/lighting.cginc
@@ -34,9 +34,10 @@ float4 getDirectLightColorIntensity() {
 	return float4(_LightColor0.xyz, _LightColor0.w);
 }
 
-float3 getIndirectSpecular(v2f i, float perceptual_roughness, float3 view_dir, float3 reflect_dir) {
+float3 getIndirectSpecular(v2f i, float perceptual_roughness, float3 view_dir, float3 reflect_dir, float3 indirect_diffuse) {
   UnityGIInput data = InitialiseUnityGIInput(i.worldPos, view_dir);
   float3 env_refl = UnityGI_prefilteredRadiance(data, perceptual_roughness, reflect_dir);
+
   return env_refl;
 }
 
@@ -173,35 +174,26 @@ float getAO(v2f i) {
 }
 
 float getSpecularAO(v2f i, Pbr pbr, LightData data, float3 reflect_dir) {
-  float spec_ao = 1;
-#if defined(_AMBIENT_OCCLUSION) || defined(_BENT_NORMALS)
   float ao_vis = 1.0;
 #if defined(_AMBIENT_OCCLUSION)
   ao_vis = data.common.ao;
 #endif
+
+  // Exposure occlusion: derive specular AO from diffuse irradiance magnitude.
+  // When IBL diffuse goes dark, attenuate specular to avoid implausible
+  // reflections. Based on filamented's IrradianceToExposureOcclusion.
+  float exposure_ao = saturate(length(data.indirect.diffuse) / _Exposure_Occlusion);
+  ao_vis *= exposure_ao;
+
 #if defined(_BENT_NORMALS)
   float3 spec_ao_normal = pbr.bent_normal;
 #else
   float3 spec_ao_normal = pbr.normal;
 #endif
-  spec_ao = computeSpecularAO(data.common.NoV, ao_vis, pbr.roughness, spec_ao_normal, -data.indirect.dir);
+  float spec_ao = computeSpecularAO(data.common.NoV, ao_vis, pbr.roughness, spec_ao_normal, -data.indirect.dir);
 #if defined(_BENT_NORMALS)
   spec_ao = saturate(lerp(1.0, spec_ao, _Bent_Normals_Strength));
 #endif
-#endif
-
-  // Didn't see a big difference in testbed, so commented out.
-  // Bent normals get us most of what we want.
-#if 0
-  // Horizon fading
-  // https://marmosetco.tumblr.com/post/81245981087
-  // The goal is to attenuate anything which points into the mesh.
-  // TODO expose fade strength as a parameter.
-  float horizon_fade_str = 1.3;
-  float horizon_fade = saturate(1.0f + horizon_fade_str * dot(pbr.normal, -reflect_dir));
-  horizon_fade *= horizon_fade;
-  spec_ao *= horizon_fade;
-#endif
 
   return spec_ao;
 }
@@ -259,13 +251,13 @@ void GetLighting(v2f i, Pbr pbr, out LightData data) {
   data.indirect.double_LoV = saturate(2.0f * indirect_LoV * indirect_LoV - 1.0f);
 
 	data.indirect.diffuse = getIndirectDiffuse(i, pbr, data);
-	data.indirect.specular = getIndirectSpecular(i, pbr.roughness_perceptual, view_dir, data.indirect.dir);
+	data.indirect.specular = getIndirectSpecular(i, pbr.roughness_perceptual, view_dir, data.indirect.dir, data.indirect.diffuse);
 
   data.common.ao = getAO(i);
   data.common.spec_ao = getSpecularAO(i, pbr, data, reflect_dir);
 
 #if defined(_CLEARCOAT)
-  data.indirect.specular_cc = getIndirectSpecular(i, pbr.cc_roughness_perceptual, view_dir, dir_cc);
+  data.indirect.specular_cc = getIndirectSpecular(i, pbr.cc_roughness_perceptual, view_dir, dir_cc, data.indirect.diffuse);
 #if defined(_CLEARCOAT_MASK)
   float cc_mask = _Clearcoat_Mask.Sample(bilinear_clamp_s, i.uv01.xy).r;
   data.indirect.specular_cc *= cc_mask;