ggx and beckmann cos_remainder_and_pdf() changes

Author: Crisspl

include/irr/builtin/glsl/bxdf/brdf/specular/beckmann.glsl

@@ -112,10 +112,6 @@ float irr_glsl_beckmann_pdf_wo_clamps(in float NdotH2, in float maxNdotV, in flo
     float dummy;
     return irr_glsl_beckmann_pdf_wo_clamps(ndf, maxNdotV,NdotV2, a2, dummy);
 }
-float irr_glsl_beckmann_pdf(in irr_glsl_IsotropicViewSurfaceInteraction i, irr_glsl_IsotropicMicrofacetCache h, in float a2)
-{
-    return irr_glsl_beckmann_pdf_wo_clamps(h.NdotH2, max(i.NdotV, 0.0), i.NdotV_squared, a2);
-}
 
 // anisotropic PDF
 float irr_glsl_beckmann_pdf_wo_clamps(in float ndf, in float maxNdotV, in float TdotV2, in float BdotV2, in float NdotV2, in float ax2, in float ay2, out float onePlusLambda_V)
@@ -134,18 +130,6 @@ float irr_glsl_beckmann_pdf_wo_clamps(in float NdotH2, in float TdotH2, in float
     return irr_glsl_beckmann_pdf_wo_clamps(ndf, maxNdotV, TdotV2, BdotV2, NdotV2, ax2, ay2, dummy);
 }
 
-float irr_glsl_beckmann_pdf(in irr_glsl_AnisotropicViewSurfaceInteraction i, irr_glsl_AnisotropicMicrofacetCache h, in float ax, in float ax2, in float ay, in float ay2)
-{
-    float TdotH2 = h.TdotH * h.TdotH;
-    float BdotH2 = h.BdotH * h.BdotH;
-    float maxNdotV = max(0.0, i.isotropic.NdotV);
-    float NdotV2 = i.isotropic.NdotV_squared;
-    float TdotV2 = i.TdotV * i.TdotV;
-    float BdotV2 = i.BdotV * i.BdotV;
-    return irr_glsl_beckmann_pdf_wo_clamps(h.isotropic.NdotH2, TdotH2, BdotH2, maxNdotV, TdotV2, BdotV2, NdotV2, ax, ax2, ay, ay2);
-}
-
-
 vec3 irr_glsl_beckmann_cos_remainder_and_pdf_wo_clamps(out float pdf, in float ndf, in float NdotL2, in float maxNdotV, in float NdotV2, in vec3 reflectance, in float a2)
 {
     float onePlusLambda_V;
@@ -156,18 +140,19 @@ vec3 irr_glsl_beckmann_cos_remainder_and_pdf_wo_clamps(out float pdf, in float n
 }
 vec3 irr_glsl_beckmann_cos_remainder_and_pdf(out float pdf, in irr_glsl_LightSample _sample, in irr_glsl_IsotropicViewSurfaceInteraction interaction, in irr_glsl_IsotropicMicrofacetCache _cache, in mat2x3 ior, in float a2)
 {
+    const float ndf = irr_glsl_beckmann(a2, _cache.NdotH2);
+    float onePlusLambda_V;
+    pdf = irr_glsl_beckmann_pdf_wo_clamps(ndf, interaction.NdotV, interaction.NdotV_squared, a2, onePlusLambda_V);
+    vec3 rem = vec3(0.0);
     if (_sample.NdotL>FLT_MIN && interaction.NdotV>FLT_MIN)
     {
-        const float ndf = irr_glsl_beckmann(a2, _cache.NdotH2);
         const vec3 reflectance = irr_glsl_fresnel_conductor(ior[0], ior[1], _cache.VdotH);
 
-        return irr_glsl_beckmann_cos_remainder_and_pdf_wo_clamps(pdf, ndf, _sample.NdotL2, interaction.NdotV, interaction.NdotV_squared, reflectance, a2);
-    }
-    else
-    {
-        pdf = irr_glsl_beckmann_pdf(interaction, _cache, a2);
-        return vec3(0.0);
+        float G2_over_G1 = irr_glsl_beckmann_smith_G2_over_G1(onePlusLambda_V, _sample.NdotL2, a2);
+        rem = reflectance * G2_over_G1;
     }
+    
+    return rem;
 }
 
 
@@ -182,29 +167,31 @@ vec3 irr_glsl_beckmann_aniso_cos_remainder_and_pdf_wo_clamps(out float pdf, in f
 }
 vec3 irr_glsl_beckmann_aniso_cos_remainder_and_pdf(out float pdf, in irr_glsl_LightSample _sample, in irr_glsl_AnisotropicViewSurfaceInteraction interaction, in irr_glsl_AnisotropicMicrofacetCache _cache, in mat2x3 ior, in float ax, in float ay)
 {    
+    const float ax2 = ax * ax;
+    const float ay2 = ay * ay;
+
+    const float TdotH2 = _cache.TdotH * _cache.TdotH;
+    const float BdotH2 = _cache.BdotH * _cache.BdotH;
+    const float TdotV2 = interaction.TdotV * interaction.TdotV;
+    const float BdotV2 = interaction.BdotV * interaction.BdotV;
+
+    const float NdotV2 = interaction.isotropic.NdotV_squared;
+
+    const float ndf = irr_glsl_beckmann(ax, ay, ax2, ay2, TdotH2, BdotH2, _cache.isotropic.NdotH2);
+    float onePlusLambda_V;
+    pdf = irr_glsl_beckmann_pdf_wo_clamps(ndf, interaction.isotropic.NdotV, TdotV2, BdotV2, NdotV2, ax2, ay2, onePlusLambda_V);
+    vec3 rem = vec3(0.0);
     if (_sample.NdotL>FLT_MIN && interaction.isotropic.NdotV>FLT_MIN)
     {
-        const float TdotH2 = _cache.TdotH*_cache.TdotH;
-        const float BdotH2 = _cache.BdotH*_cache.BdotH;
-
         const float TdotL2 = _sample.TdotL*_sample.TdotL;
         const float BdotL2 = _sample.BdotL*_sample.BdotL;
 
-        const float TdotV2 = interaction.TdotV*interaction.TdotV;
-        const float BdotV2 = interaction.BdotV*interaction.BdotV;
-    
-        const float ax2 = ax*ax;
-        const float ay2 = ay*ay;
-        const float ndf = irr_glsl_beckmann(ax, ay, ax2, ay2, TdotH2, BdotH2, _cache.isotropic.NdotH2);
         const vec3 reflectance = irr_glsl_fresnel_conductor(ior[0], ior[1], _cache.isotropic.VdotH);
 
-	    return irr_glsl_beckmann_aniso_cos_remainder_and_pdf_wo_clamps(pdf, ndf, _sample.NdotL2,TdotL2,BdotL2, interaction.isotropic.NdotV,TdotV2,BdotV2, interaction.isotropic.NdotV_squared, reflectance, ax2, ay2);
-    }
-    else
-    {
-        pdf = irr_glsl_beckmann_pdf(interaction, _cache, ax, ax*ax, ay, ay*ay);
-        return vec3(0.0);
+	    rem = irr_glsl_beckmann_aniso_cos_remainder_and_pdf_wo_clamps(pdf, ndf, _sample.NdotL2, TdotL2, BdotL2, interaction.isotropic.NdotV, TdotV2, BdotV2, NdotV2, reflectance, ax2, ay2);
     }
+    
+    return rem;
 }
 
 

include/irr/builtin/glsl/bxdf/brdf/specular/ggx.glsl

@@ -142,10 +142,6 @@ float irr_glsl_ggx_pdf_wo_clamps(in float NdotH2, in float maxNdotV, in float Nd
 
     return irr_glsl_ggx_pdf_wo_clamps(ndf, devsh_v, maxNdotV);
 }
-float irr_glsl_ggx_pdf(in irr_glsl_IsotropicViewSurfaceInteraction i, irr_glsl_IsotropicMicrofacetCache h, in float a2)
-{
-    return irr_glsl_ggx_pdf_wo_clamps(h.NdotH2, max(i.NdotV, 0.0), i.NdotV_squared, a2);
-}
 
 float irr_glsl_ggx_pdf_wo_clamps(in float NdotH2, in float TdotH2, in float BdotH2, in float maxNdotV, in float NdotV2, in float TdotV2, in float BdotV2, in float ax, in float ay, in float ax2, in float ay2)
 {
@@ -154,16 +150,6 @@ float irr_glsl_ggx_pdf_wo_clamps(in float NdotH2, in float TdotH2, in float Bdot
 
     return irr_glsl_ggx_pdf_wo_clamps(ndf, devsh_v, maxNdotV);
 }
-float irr_glsl_ggx_pdf(in irr_glsl_AnisotropicViewSurfaceInteraction i, irr_glsl_AnisotropicMicrofacetCache h, in float ax, in float ay, in float ax2, in float ay2)
-{
-    float TdotH2 = h.TdotH*h.TdotH;
-    float BdotH2 = h.BdotH*h.BdotH;
-    float maxNdotV = max(0.0,i.isotropic.NdotV);
-    float NdotV2 = i.isotropic.NdotV_squared;
-    float TdotV2 = i.TdotV*i.TdotV;
-    float BdotV2 = i.BdotV*i.BdotV;
-    return irr_glsl_ggx_pdf_wo_clamps(h.isotropic.NdotH2, TdotH2, BdotH2, maxNdotV, NdotV2, TdotV2, BdotV2, ax, ay, ax2, ay2);
-}
 
 
 vec3 irr_glsl_ggx_cos_remainder_and_pdf_wo_clamps(out float pdf, in float ndf, in float maxNdotL, in float NdotL2, in float maxNdotV, in float NdotV2, in vec3 reflectance, in float a2)
@@ -179,18 +165,20 @@ vec3 irr_glsl_ggx_cos_remainder_and_pdf_wo_clamps(out float pdf, in float ndf, i
 
 vec3 irr_glsl_ggx_cos_remainder_and_pdf(out float pdf, in irr_glsl_LightSample _sample, in irr_glsl_IsotropicViewSurfaceInteraction interaction, in irr_glsl_IsotropicMicrofacetCache _cache, in mat2x3 ior, in float a2)
 {    
+    const float one_minus_a2 = 1.0 - a2;
+    const float ndf = irr_glsl_ggx_trowbridge_reitz(a2, _cache.NdotH2);
+    const float devsh_v = irr_glsl_smith_ggx_devsh_part(interaction.NdotV_squared, a2, one_minus_a2);
+    pdf = irr_glsl_ggx_pdf_wo_clamps(ndf, devsh_v, interaction.NdotV);
+    vec3 rem = vec3(0.0);
     if (_sample.NdotL>FLT_MIN && interaction.NdotV>FLT_MIN)
     {
-        const float ndf = irr_glsl_ggx_trowbridge_reitz(a2, _cache.NdotH2);
         const vec3 reflectance = irr_glsl_fresnel_conductor(ior[0], ior[1], _cache.VdotH);
+        const float G2_over_G1 = irr_glsl_ggx_smith_G2_over_G1_devsh(_sample.NdotL, _sample.NdotL2, interaction.NdotV, devsh_v, a2, one_minus_a2);
 
-        return irr_glsl_ggx_cos_remainder_and_pdf_wo_clamps(pdf, ndf, _sample.NdotL, _sample.NdotL2, interaction.NdotV, interaction.NdotV_squared, reflectance, a2);
-    }
-    else
-    {
-        pdf = irr_glsl_ggx_pdf(interaction,_cache,a2);
-        return vec3(0.0);
+        rem = reflectance * G2_over_G1;
     }
+
+    return rem;
 }
 
 
@@ -210,29 +198,36 @@ vec3 irr_glsl_ggx_aniso_cos_remainder_and_pdf_wo_clamps(out float pdf, in float
 
 vec3 irr_glsl_ggx_aniso_cos_remainder_and_pdf(out float pdf, in irr_glsl_LightSample _sample, in irr_glsl_AnisotropicViewSurfaceInteraction interaction, in irr_glsl_AnisotropicMicrofacetCache _cache, in mat2x3 ior, in float ax, in float ay)
 {
+    const float ax2 = ax * ax;
+    const float ay2 = ay * ay;
+
+    const float TdotV2 = interaction.TdotV * interaction.TdotV;
+    const float BdotV2 = interaction.BdotV * interaction.BdotV;
+    const float NdotV2 = interaction.isotropic.NdotV_squared;
+
+    const float TdotH2 = _cache.TdotH * _cache.TdotH;
+    const float BdotH2 = _cache.BdotH * _cache.BdotH;
+
+    const float devsh_v = irr_glsl_smith_ggx_devsh_part(TdotV2, BdotV2, NdotV2, ax2, ay2);
+    const float ndf = irr_glsl_ggx_aniso(TdotH2, BdotH2, _cache.isotropic.NdotH2, ax, ay, ax2, ay2);
+    pdf = irr_glsl_ggx_pdf_wo_clamps(ndf, devsh_v, interaction.isotropic.NdotV);
+    vec3 rem = vec3(0.0);
     if (_sample.NdotL>FLT_MIN && interaction.isotropic.NdotV>FLT_MIN)
     {
-        const float TdotH2 = _cache.TdotH*_cache.TdotH;
-        const float BdotH2 = _cache.BdotH*_cache.BdotH;
-
         const float TdotL2 = _sample.TdotL*_sample.TdotL;
         const float BdotL2 = _sample.BdotL*_sample.BdotL;
 
-        const float TdotV2 = interaction.TdotV*interaction.TdotV;
-        const float BdotV2 = interaction.BdotV*interaction.BdotV;
-
-        const float ax2 = ax*ax;
-        const float ay2 = ay*ay;
-        const float ndf = irr_glsl_ggx_aniso(TdotH2,BdotH2,_cache.isotropic.NdotH2, ax, ay, ax2, ay2);
         const vec3 reflectance = irr_glsl_fresnel_conductor(ior[0], ior[1], _cache.isotropic.VdotH);
+        const float G2_over_G1 = irr_glsl_ggx_smith_G2_over_G1_devsh(
+            _sample.NdotL, TdotL2, BdotL2, _sample.NdotL2,
+            interaction.isotropic.NdotV, devsh_v,
+            ax2, ay2
+        );
 
-	    return irr_glsl_ggx_aniso_cos_remainder_and_pdf_wo_clamps(pdf, ndf, _sample.NdotL, _sample.NdotL2, TdotL2, BdotL2, interaction.isotropic.NdotV, TdotV2, BdotV2, interaction.isotropic.NdotV_squared, reflectance, ax2, ay2);
-    }
-    else
-    {
-        pdf = irr_glsl_ggx_pdf(interaction, _cache, ax, ay, ax*ax, ay*ay);
-        return vec3(0.0);
+        rem = reflectance * G2_over_G1;
     }
+
+    return rem;
 }
 
 #endif

include/irr/builtin/glsl/sampling/cos_weighted.glsl

@@ -47,7 +47,7 @@ float irr_glsl_projected_sphere_remainder_and_pdf(out float pdf, in vec3 L)
 
 float irr_glsl_projected_sphere_pdf(in float L_z)
 {
-    return 0.5*L_z*irr_glsl_RECIPROCAL_PI;
+    return 0.5*irr_glsl_projected_hemisphere_pdf(L_z);
 }
 
 #endif