Merge branch 'shader_pipeline_irrlichtbaw' of https://github.com/Devsh-Graphics-Programming/Nabla into master

Author: Przemog1

examples_tests/42.FragmentShaderPathTracer/common.glsl

@@ -203,7 +203,7 @@ BSDFNode bsdfs[BSDF_COUNT] = {
     {{uvec4(floatBitsToUint(vec3(1.02,1.02,1.3)),CONDUCTOR_OP),floatBitsToUint(vec4(1.0,1.0,2.0,0.0))}},
     {{uvec4(floatBitsToUint(vec3(1.02,1.3,1.02)),CONDUCTOR_OP),floatBitsToUint(vec4(1.0,2.0,1.0,0.0))}},
     {{uvec4(floatBitsToUint(vec3(1.02,1.3,1.02)),CONDUCTOR_OP),floatBitsToUint(vec4(1.0,2.0,1.0,0.15))}},
-    {{uvec4(floatBitsToUint(vec3(1.4,1.45,1.5)),DIELECTRIC_OP),floatBitsToUint(vec4(0.0,0.0,0.0,0.125))}}
+    {{uvec4(floatBitsToUint(vec3(1.4,1.45,1.5)),DIELECTRIC_OP),floatBitsToUint(vec4(0.0,0.0,0.0,0.0625))}}
 };
 
 
@@ -281,7 +281,7 @@ bool anyHitProgram(in ImmutableRay_t _immutable)
 }
 
 
-#define INTERSECTION_ERROR_BOUND_LOG2 (-9.0)
+#define INTERSECTION_ERROR_BOUND_LOG2 (-8.0)
 float getTolerance_common(in int depth)
 {
     float depthRcp = 1.0/float(depth);
@@ -333,6 +333,7 @@ void missProgram()
 #include <irr/builtin/glsl/bxdf/bsdf/diffuse/lambert.glsl>
 #include <irr/builtin/glsl/bxdf/bsdf/specular/dielectric.glsl>
 #include <irr/builtin/glsl/bxdf/bsdf/specular/beckmann.glsl>
+#include <irr/builtin/glsl/bxdf/bsdf/specular/ggx.glsl>
 irr_glsl_LightSample irr_glsl_bsdf_cos_generate(in irr_glsl_AnisotropicViewSurfaceInteraction interaction, in vec3 u, in BSDFNode bsdf, in float monochromeEta, out irr_glsl_AnisotropicMicrofacetCache _cache)
 {
     const float a = BSDFNode_getRoughness(bsdf);
@@ -353,7 +354,7 @@ irr_glsl_LightSample irr_glsl_bsdf_cos_generate(in irr_glsl_AnisotropicViewSurfa
             smpl = irr_glsl_ggx_cos_generate(interaction,u.xy,a,a,_cache);
             break;
         default:
-            smpl = irr_glsl_beckmann_dielectric_cos_generate(interaction,u,a,a,monochromeEta,_cache);
+            smpl = irr_glsl_ggx_dielectric_cos_generate(interaction,u,a,a,monochromeEta,_cache);
             break;
     }
     return smpl;
@@ -398,7 +399,7 @@ vec3 irr_glsl_bsdf_cos_remainder_and_pdf(out float pdf, in irr_glsl_LightSample
                 remainder = irr_glsl_ggx_cos_remainder_and_pdf_wo_clamps(pdf,irr_glsl_ggx_trowbridge_reitz(a2,_cache.isotropic.NdotH2),clampedNdotL,_sample.NdotL2,clampedNdotV,interaction.isotropic.NdotV_squared,reflectance,a2);
                 break;
             default:
-                remainder = vec3(irr_glsl_beckmann_dielectric_cos_remainder_and_pdf(pdf, _sample, interaction.isotropic, _cache.isotropic, monochromeEta, a2));
+                remainder = vec3(irr_glsl_ggx_dielectric_cos_remainder_and_pdf(pdf, _sample, interaction.isotropic, _cache.isotropic, monochromeEta, a*a));
                 break;
         }
     }

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

@@ -59,6 +59,7 @@ vec3 irr_glsl_beckmann_cos_generate_wo_clamps(in vec3 localV, in vec2 u, in floa
 
             b -= value/derivative;
         }
+        // TODO: investigate if we can replace these two erf^-1 calls with a box muller transform
         slope.x = irr_glsl_erfInv(b);
         slope.y = irr_glsl_erfInv(2.0 * max(u.y,1.0e-6) - 1.0);
     }
@@ -77,6 +78,7 @@ vec3 irr_glsl_beckmann_cos_generate_wo_clamps(in vec3 localV, in vec2 u, in floa
     return normalize(vec3(-slope, 1.0));
 }
 
+// TODO: unifty the two following functions into `irr_glsl_microfacet_BRDF_cos_generate_wo_clamps(vec3 H,...)` and `irr_glsl_microfacet_BRDF_cos_generate` or at least a auto declaration macro in lieu of a template
 irr_glsl_LightSample irr_glsl_beckmann_cos_generate_wo_clamps(in vec3 localV, in mat3 m, in vec2 u, in float ax, in float ay, out irr_glsl_AnisotropicMicrofacetCache _cache)
 {
     const vec3 H = irr_glsl_beckmann_cos_generate_wo_clamps(localV,u,ax,ay);
@@ -192,25 +194,21 @@ vec3 irr_glsl_beckmann_aniso_cos_remainder_and_pdf(out float pdf, in irr_glsl_Li
 }
 
 
-
-float irr_glsl_beckmann_height_correlated_cos_eval_DG_wo_clamps(in float NdotH2, in float NdotL2, in float maxNdotV, in float NdotV2, in float a2)
+float irr_glsl_beckmann_height_correlated_cos_eval_DG_wo_clamps(in float NdotH2, in float NdotL2, in float NdotV2, in float a2)
 {
-    float ndf = irr_glsl_beckmann(a2, NdotH2);
-    float scalar_part = ndf / (4.0 * maxNdotV);
+    float NG = irr_glsl_beckmann(a2, NdotH2);
     if  (a2>FLT_MIN)
-    {
-        float g = irr_glsl_beckmann_smith_correlated(NdotV2, NdotL2, a2);
-        scalar_part *= g;
-    }
+        NG *= irr_glsl_beckmann_smith_correlated(NdotV2, NdotL2, a2);
 
-    return scalar_part;
+    return NG;
 }
 vec3 irr_glsl_beckmann_height_correlated_cos_eval_wo_clamps(in float NdotH2, in float NdotL2, in float maxNdotV, in float NdotV2, in float VdotH, in mat2x3 ior, in float a2)
 {
-    float scalar_part = irr_glsl_beckmann_height_correlated_cos_eval_DG_wo_clamps(NdotH2, NdotL2, maxNdotV, NdotV2, a2);
-    vec3 fr = irr_glsl_fresnel_conductor(ior[0], ior[1], VdotH);
-    
-    return scalar_part*fr;
+    const float NG = irr_glsl_beckmann_height_correlated_cos_eval_DG_wo_clamps(NdotH2, NdotL2, NdotV2, a2);
+
+    const vec3 fr = irr_glsl_fresnel_conductor(ior[0], ior[1], VdotH);
+
+    return fr*irr_glsl_microfacet_to_light_measure_transform(NG,maxNdotV);
 }
 vec3 irr_glsl_beckmann_height_correlated_cos_eval(in irr_glsl_LightSample _sample, in irr_glsl_IsotropicViewSurfaceInteraction interaction, in irr_glsl_IsotropicMicrofacetCache _cache, in mat2x3 ior, in float a2)
 {
@@ -220,24 +218,21 @@ vec3 irr_glsl_beckmann_height_correlated_cos_eval(in irr_glsl_LightSample _sampl
         return vec3(0.0);
 }
 
-float irr_glsl_beckmann_aniso_height_correlated_cos_eval_DG_wo_clamps(in float NdotH2, in float TdotH2, in float BdotH2, in float NdotL2, in float TdotL2, in float BdotL2, in float maxNdotV, in float NdotV2, in float TdotV2, in float BdotV2, in float ax, in float ax2, in float ay, in float ay2)
+float irr_glsl_beckmann_aniso_height_correlated_cos_eval_DG_wo_clamps(in float NdotH2, in float TdotH2, in float BdotH2, in float NdotL2, in float TdotL2, in float BdotL2, in float NdotV2, in float TdotV2, in float BdotV2, in float ax, in float ax2, in float ay, in float ay2)
 {
-    float ndf = irr_glsl_beckmann(ax, ay, ax2, ay2, TdotH2, BdotH2, NdotH2);
-    float scalar_part = ndf / (4.0 * maxNdotV);
+    float NG = irr_glsl_beckmann(ax, ay, ax2, ay2, TdotH2, BdotH2, NdotH2);
     if (ax>FLT_MIN || ay>FLT_MIN)
-    {
-        float g = irr_glsl_beckmann_smith_correlated(TdotV2, BdotV2, NdotV2, TdotL2, BdotL2, NdotL2, ax2, ay2);
-        scalar_part *= g;
-    }
+        NG *= irr_glsl_beckmann_smith_correlated(TdotV2, BdotV2, NdotV2, TdotL2, BdotL2, NdotL2, ax2, ay2);
 
-    return scalar_part;
+    return NG;
 }
 vec3 irr_glsl_beckmann_aniso_height_correlated_cos_eval_wo_clamps(in float NdotH2, in float TdotH2, in float BdotH2, in float NdotL2, in float TdotL2, in float BdotL2, in float maxNdotV, in float NdotV2, in float TdotV2, in float BdotV2, in float VdotH, in mat2x3 ior, in float ax, in float ax2, in float ay, in float ay2)
 {
-    float scalar_part = irr_glsl_beckmann_aniso_height_correlated_cos_eval_DG_wo_clamps(NdotH2,TdotH2,BdotH2, NdotL2,TdotL2,BdotL2, maxNdotV,NdotV2,TdotV2,BdotV2, ax, ax2, ay, ay2);
-    vec3 fr = irr_glsl_fresnel_conductor(ior[0], ior[1], VdotH);
+    const float NG = irr_glsl_beckmann_aniso_height_correlated_cos_eval_DG_wo_clamps(NdotH2,TdotH2,BdotH2, NdotL2,TdotL2,BdotL2, NdotV2,TdotV2,BdotV2, ax, ax2, ay, ay2);
+
+    const vec3 fr = irr_glsl_fresnel_conductor(ior[0], ior[1], VdotH);
 
-    return scalar_part*fr;
+    return fr*irr_glsl_microfacet_to_light_measure_transform(NG,maxNdotV);
 }
 vec3 irr_glsl_beckmann_aniso_height_correlated_cos_eval(in irr_glsl_LightSample _sample, in irr_glsl_AnisotropicViewSurfaceInteraction interaction, in irr_glsl_AnisotropicMicrofacetCache _cache, in mat2x3 ior, in float ax, in float ay)
 {    

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

@@ -60,27 +60,23 @@ vec3 irr_glsl_blinn_phong_conductor_cos_remainder_and_pdf(out float pdf, in irr_
 }
 */
 
-float irr_glsl_blinn_phong_cos_eval_DG_wo_clamps(in float NdotH, in float maxNdotV, in float NdotV_squared, in float NdotL2, in float n, in float a2)
+float irr_glsl_blinn_phong_cos_eval_DG_wo_clamps(in float NdotH, in float NdotV_squared, in float NdotL2, in float n, in float a2)
 {
-    float d = irr_glsl_blinn_phong(NdotH, n);
-    float scalar_part = d/(4.0*maxNdotV);
+    float NG = irr_glsl_blinn_phong(NdotH, n);
     if (a2>FLT_MIN)
-    {
-        float g = irr_glsl_beckmann_smith_correlated(NdotV_squared, NdotL2, a2);
-        scalar_part *= g;
-    }
+        NG *= irr_glsl_beckmann_smith_correlated(NdotV_squared, NdotL2, a2);
     return scalar_part;
 }
-float irr_glsl_blinn_phong_cos_eval_DG_wo_clamps(in float NdotH, in float maxNdotV, in float NdotV_squared, in float NdotL2, in float n)
+float irr_glsl_blinn_phong_cos_eval_DG_wo_clamps(in float NdotH, in float NdotV_squared, in float NdotL2, in float n)
 {
     float a2 = irr_glsl_phong_exp_to_alpha2(n);
-    return irr_glsl_blinn_phong_cos_eval_DG_wo_clamps(NdotH, maxNdotV, NdotV_squared, NdotL2, n, a2);
+    return irr_glsl_blinn_phong_cos_eval_DG_wo_clamps(NdotH, NdotV_squared, NdotL2, n, a2);
 }
 
 vec3 irr_glsl_blinn_phong_cos_eval_wo_clamps(in float NdotH, in float maxNdotV, in float NdotV_squared, in float NdotL2, in float VdotH, in float n, in mat2x3 ior, in float a2)
 {
-    float scalar_part = irr_glsl_blinn_phong_cos_eval_DG_wo_clamps(NdotH, maxNdotV, NdotV_squared, NdotL2, n, a2);
-    return scalar_part*irr_glsl_fresnel_conductor(ior[0], ior[1], VdotH);
+    float scalar_part = irr_glsl_blinn_phong_cos_eval_DG_wo_clamps(NdotH, NdotV_squared, NdotL2, n, a2);
+    return irr_glsl_fresnel_conductor(ior[0], ior[1], VdotH)*irr_glsl_microfacet_to_light_measure_transform(scalar_part,maxNdotV);
 }
 vec3 irr_glsl_blinn_phong_cos_eval_wo_clamps(in float NdotH, in float maxNdotV, in float NdotV_squared, in float NdotL2, in float VdotH, in float n, in mat2x3 ior)
 {
@@ -96,31 +92,26 @@ vec3 irr_glsl_blinn_phong_cos_eval(in irr_glsl_LightSample _sample, in irr_glsl_
 }
 
 
-float irr_glsl_blinn_phong_cos_eval_DG_wo_clamps(in float NdotH, in float NdotH2, in float TdotH2, in float BdotH2, float TdotL2, float BdotL2, in float maxNdotV, in float TdotV2, in float BdotV2, in float NdotV_squared, in float NdotL2, in float nx, in float ny, in float ax2, in float ay2)
+float irr_glsl_blinn_phong_cos_eval_DG_wo_clamps(in float NdotH, in float NdotH2, in float TdotH2, in float BdotH2, float TdotL2, float BdotL2, in float TdotV2, in float BdotV2, in float NdotV_squared, in float NdotL2, in float nx, in float ny, in float ax2, in float ay2)
 {
     float d = irr_glsl_blinn_phong(NdotH, 1.0/(1.0-NdotH2), TdotH2, BdotH2, nx, ny);
-    float scalar_part = d/(4.0*maxNdotV);
     if (ax2>FLT_MIN || ay2>FLT_MIN)
-    {
-        float g = irr_glsl_beckmann_smith_correlated(TdotV2, BdotV2, NdotV_squared, TdotL2, BdotL2, NdotL2, ax2, ay2);
-        scalar_part *= g;
-    }
-
+        NG *= irr_glsl_beckmann_smith_correlated(TdotV2, BdotV2, NdotV_squared, TdotL2, BdotL2, NdotL2, ax2, ay2);
     return scalar_part;
 }
-float irr_glsl_blinn_phong_cos_eval_DG_wo_clamps(in float NdotH, in float NdotH2, in float TdotH2, in float BdotH2, in float TdotL2, in float BdotL2, in float maxNdotV, in float TdotV2, in float BdotV2, in float NdotV_squared, in float NdotL2, in float nx, in float ny)
+float irr_glsl_blinn_phong_cos_eval_DG_wo_clamps(in float NdotH, in float NdotH2, in float TdotH2, in float BdotH2, in float TdotL2, in float BdotL2, in float TdotV2, in float BdotV2, in float NdotV_squared, in float NdotL2, in float nx, in float ny)
 {
     float ax2 = irr_glsl_phong_exp_to_alpha2(nx);
     float ay2 = irr_glsl_phong_exp_to_alpha2(ny);
 
-    return irr_glsl_blinn_phong_cos_eval_DG_wo_clamps(NdotH, NdotH2, TdotH2, BdotH2, TdotL2, BdotL2, maxNdotV, TdotV2, BdotV2, NdotV_squared, NdotL2, nx, ny, ax2, ay2);
+    return irr_glsl_blinn_phong_cos_eval_DG_wo_clamps(NdotH, NdotH2, TdotH2, BdotH2, TdotL2, BdotL2, TdotV2, BdotV2, NdotV_squared, NdotL2, nx, ny, ax2, ay2);
 }
 
 vec3 irr_glsl_blinn_phong_cos_eval_wo_clamps(in float NdotH, in float NdotH2, in float TdotH2, in float BdotH2, in float TdotL2, in float BdotL2, in float maxNdotV, in float TdotV2, in float BdotV2, in float NdotV_squared, in float NdotL2, in float VdotH, in float nx, in float ny, in mat2x3 ior, in float ax2, in float ay2)
 {
     float scalar_part = irr_glsl_blinn_phong_cos_eval_DG_wo_clamps(NdotH, NdotH2, TdotH2, BdotH2, TdotL2, BdotL2, maxNdotV, TdotV2, BdotV2, NdotV_squared, NdotL2, nx, ny, ax2, ay2);
 
-    return scalar_part*irr_glsl_fresnel_conductor(ior[0], ior[1], VdotH);
+    return irr_glsl_fresnel_conductor(ior[0], ior[1], VdotH)*irr_glsl_microfacet_to_light_measure_transform(scalar_part,maxNdotV);
 }
 vec3 irr_glsl_blinn_phong_cos_eval_wo_clamps(in float NdotH, in float NdotH2, in float TdotH2, in float BdotH2, in float TdotL2, in float BdotL2, in float maxNdotV, in float TdotV2, in float BdotV2, in float NdotV_squared, in float NdotL2, in float VdotH, in float nx, in float ny, in mat2x3 ior)
 {

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

@@ -20,27 +20,25 @@ vec3 irr_glsl_ggx_height_correlated_aniso_cos_eval(in irr_glsl_BSDFAnisotropicPa
 //defined using NDF function with better API (compared to burley used above) and new impl of correlated smith
 float irr_glsl_ggx_height_correlated_aniso_cos_eval_DG_wo_clamps(in float NdotH2, in float TdotH2, in float BdotH2, in float maxNdotL, in float NdotL2, in float TdotL2, in float BdotL2, in float maxNdotV, in float NdotV2, in float TdotV2, in float BdotV2, in float ax, in float ax2, in float ay, in float ay2)
 {
-    float ndf = irr_glsl_ggx_aniso(TdotH2,BdotH2,NdotH2, ax, ay, ax2, ay2);
-    float scalar_part = ndf*maxNdotL;
+    float NG = irr_glsl_ggx_aniso(TdotH2,BdotH2,NdotH2, ax, ay, ax2, ay2);
     if (ax>FLT_MIN || ay>FLT_MIN)
     {
-        float g = irr_glsl_ggx_smith_correlated_wo_numerator(
+        NG *= irr_glsl_ggx_smith_correlated_wo_numerator(
             maxNdotV, TdotV2, BdotV2, NdotV2,
             maxNdotL, TdotL2, BdotL2, NdotL2,
             ax2, ay2
         );
-        scalar_part *= g;
     }
 
-    return scalar_part;
+    return NG;
 }
 
 vec3 irr_glsl_ggx_height_correlated_aniso_cos_eval_wo_clamps(in float NdotH2, in float TdotH2, in float BdotH2, in float maxNdotL, in float NdotL2, in float TdotL2, in float BdotL2, in float maxNdotV, in float NdotV2, in float TdotV2, in float BdotV2, in float VdotH, in mat2x3 ior, in float ax, in float ax2, in float ay, in float ay2)
 {
-    float scalar_part = irr_glsl_ggx_height_correlated_aniso_cos_eval_DG_wo_clamps(NdotH2,TdotH2,BdotH2,maxNdotL,NdotL2,TdotL2,BdotL2,maxNdotV,NdotV2,TdotV2,BdotV2,ax,ax2,ay,ay2);
+    float NG_already_in_reflective_dL_measure = irr_glsl_ggx_height_correlated_aniso_cos_eval_DG_wo_clamps(NdotH2,TdotH2,BdotH2,maxNdotL,NdotL2,TdotL2,BdotL2,maxNdotV,NdotV2,TdotV2,BdotV2,ax,ax2,ay,ay2);
 
     vec3 fr = irr_glsl_fresnel_conductor(ior[0], ior[1], VdotH);
-    return fr*scalar_part;
+    return fr*irr_glsl_ggx_microfacet_to_light_measure_transform(NG_already_in_reflective_dL_measure,maxNdotL);
 }
 
 vec3 irr_glsl_ggx_height_correlated_aniso_cos_eval(in irr_glsl_LightSample _sample, in irr_glsl_AnisotropicViewSurfaceInteraction interaction, in irr_glsl_AnisotropicMicrofacetCache _cache, in mat2x3 ior, in float ax, in float ay)
@@ -64,23 +62,20 @@ vec3 irr_glsl_ggx_height_correlated_aniso_cos_eval(in irr_glsl_LightSample _samp
 
 float irr_glsl_ggx_height_correlated_cos_eval_DG_wo_clamps(in float NdotH2, in float maxNdotL, in float NdotL2, in float maxNdotV, in float NdotV2, in float a2)
 {
-    float ndf = irr_glsl_ggx_trowbridge_reitz(a2, NdotH2);
-    float scalar_part = ndf*maxNdotL;
+    float NG = irr_glsl_ggx_trowbridge_reitz(a2, NdotH2);
     if (a2>FLT_MIN)
-    {
-        float g = irr_glsl_ggx_smith_correlated_wo_numerator(maxNdotV, NdotV2, maxNdotL, NdotL2, a2);
-        scalar_part *= g;
-    }
+        NG *= irr_glsl_ggx_smith_correlated_wo_numerator(maxNdotV, NdotV2, maxNdotL, NdotL2, a2);
 
-    return scalar_part;
+    return NG;
 }
 
 vec3 irr_glsl_ggx_height_correlated_cos_eval_wo_clamps(in float NdotH2, in float maxNdotL, in float NdotL2, in float maxNdotV, in float NdotV2, in float VdotH, in mat2x3 ior, in float a2)
 {
-    float scalar_part = irr_glsl_ggx_height_correlated_cos_eval_DG_wo_clamps(NdotH2, maxNdotL, NdotL2, maxNdotV, NdotV2, a2);
+    float NG_already_in_reflective_dL_measure = irr_glsl_ggx_height_correlated_cos_eval_DG_wo_clamps(NdotH2, maxNdotL, NdotL2, maxNdotV, NdotV2, a2);
 
     vec3 fr = irr_glsl_fresnel_conductor(ior[0], ior[1], VdotH);
-    return fr*scalar_part;
+
+    return fr*irr_glsl_ggx_microfacet_to_light_measure_transform(NG_already_in_reflective_dL_measure,maxNdotL);
 }
 
 vec3 irr_glsl_ggx_height_correlated_cos_eval(in irr_glsl_LightSample _sample, in irr_glsl_IsotropicViewSurfaceInteraction interaction, in irr_glsl_IsotropicMicrofacetCache _cache, in mat2x3 ior, in float a2)
@@ -116,6 +111,7 @@ vec3 irr_glsl_ggx_cos_generate(in vec3 localV, in vec2 u, in float _ax, in float
     return normalize(vec3(_ax*H.x, _ay*H.y, H.z));
 }
 
+// TODO: unifty the two following functions into `irr_glsl_microfacet_BRDF_cos_generate_wo_clamps(vec3 H,...)` and `irr_glsl_microfacet_BRDF_cos_generate` or at least a auto declaration macro in lieu of a template
 irr_glsl_LightSample irr_glsl_ggx_cos_generate_wo_clamps(in vec3 localV, in mat3 m, in vec2 u, in float _ax, in float _ay, out irr_glsl_AnisotropicMicrofacetCache _cache)
 {
     const vec3 H = irr_glsl_ggx_cos_generate(localV,u,_ax,_ay);
@@ -137,7 +133,7 @@ irr_glsl_LightSample irr_glsl_ggx_cos_generate(in irr_glsl_AnisotropicViewSurfac
 
 float irr_glsl_ggx_pdf_wo_clamps(in float ndf, in float devsh_v, in float maxNdotV)
 {
-    return ndf * irr_glsl_GGXSmith_G1_wo_numerator(maxNdotV, devsh_v) * 0.5;
+    return irr_glsl_smith_VNDF_pdf_wo_clamps(ndf,irr_glsl_GGXSmith_G1_wo_numerator(maxNdotV,devsh_v));
 }
 float irr_glsl_ggx_pdf_wo_clamps(in float NdotH2, in float maxNdotV, in float NdotV2, in float a2)
 {
@@ -159,11 +155,11 @@ float irr_glsl_ggx_pdf_wo_clamps(in float NdotH2, in float TdotH2, in float Bdot
 
 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)
 {
-    float one_minus_a2 = 1.0 - a2;
-    float devsh_v = irr_glsl_smith_ggx_devsh_part(NdotV2, a2, one_minus_a2);
+    const float one_minus_a2 = 1.0 - a2;
+    const float devsh_v = irr_glsl_smith_ggx_devsh_part(NdotV2, a2, one_minus_a2);
     pdf = irr_glsl_ggx_pdf_wo_clamps(ndf, devsh_v, maxNdotV);
 
-    float G2_over_G1 = irr_glsl_ggx_smith_G2_over_G1_devsh(maxNdotL, NdotL2, maxNdotV, devsh_v, a2, one_minus_a2);
+    const float G2_over_G1 = irr_glsl_ggx_smith_G2_over_G1_devsh(maxNdotL, NdotL2, maxNdotV, devsh_v, a2, one_minus_a2);
 
     return reflectance * G2_over_G1;
 }
@@ -175,7 +171,7 @@ vec3 irr_glsl_ggx_cos_remainder_and_pdf(out float pdf, in irr_glsl_LightSample _
         const float ndf = irr_glsl_ggx_trowbridge_reitz(a2, _cache.NdotH2);
         const vec3 reflectance = irr_glsl_fresnel_conductor(ior[0], ior[1], _cache.VdotH);
 
-        return irr_glsl_ggx_cos_remainder_and_pdf_wo_clamps(pdf, ndf, max(_sample.NdotL,0.0), _sample.NdotL2, max(interaction.NdotV,0.0), interaction.NdotV_squared, reflectance, 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
     {
@@ -215,9 +211,9 @@ vec3 irr_glsl_ggx_aniso_cos_remainder_and_pdf(out float pdf, in irr_glsl_LightSa
         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);
-	    return irr_glsl_ggx_aniso_cos_remainder_and_pdf_wo_clamps(pdf, ndf, max(_sample.NdotL, 0.0), _sample.NdotL2, TdotL2, BdotL2, max(interaction.isotropic.NdotV, 0.0), TdotV2, BdotV2, interaction.isotropic.NdotV_squared, reflectance, 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
     {