Work in progress

libraries/pbrlib/genglsl/lib/mx_closure_type.glsl

@@ -7,11 +7,19 @@
 #define CLOSURE_TYPE_INDIRECT 3
 #define CLOSURE_TYPE_EMISSION 4
 
-struct ClosureData {
+struct ClosureData
+{
     int closureType;
     vec3 L;
     vec3 V;
     vec3 N;
     vec3 P;
     float occlusion;
 };
+
+// Enforce that the given normal is forward-facing in the context
+// of the specified closure.
+vec3 mx_forward_facing_normal(vec3 N, ClosureData closureData)
+{
+    return dot(closureData.N, closureData.V) < 0.0 ? -N : N;
+}

libraries/pbrlib/genglsl/lib/mx_environment_prefilter.glsl

@@ -9,7 +9,6 @@ float mx_latlong_alpha_to_lod(float alpha)
 
 vec3 mx_environment_radiance(vec3 N, vec3 V, vec3 X, vec2 alpha, int distribution, FresnelData fd)
 {
-    N = mx_forward_facing_normal(N, V);
     vec3 L = fd.refraction ? mx_refraction_solid_sphere(-V, N, fd.ior.x) : -reflect(V, N);
 
     float NdotV = clamp(dot(N, V), M_FLOAT_EPS, 1.0);

libraries/pbrlib/genglsl/lib/mx_microfacet.glsl

@@ -52,12 +52,6 @@ vec3 mx_fresnel_schlick(float cosTheta, vec3 F0, vec3 F90, float exponent)
     return mix(F0, F90, pow(x, exponent));
 }
 
-// Enforce that the given normal is forward-facing from the specified view direction.
-vec3 mx_forward_facing_normal(vec3 N, vec3 V)
-{
-    return (dot(N, V) < 0.0) ? -N : N;
-}
-
 // https://www.graphics.rwth-aachen.de/publication/2/jgt.pdf
 float mx_golden_ratio_sequence(int i)
 {

libraries/pbrlib/genglsl/mx_burley_diffuse_bsdf.glsl

@@ -13,7 +13,7 @@ void mx_burley_diffuse_bsdf(ClosureData closureData, float weight, vec3 color, f
     vec3 V = closureData.V;
     vec3 L = closureData.L;
 
-    N = mx_forward_facing_normal(N, V);
+    N = mx_forward_facing_normal(N, closureData);
     float NdotV = clamp(dot(N, V), M_FLOAT_EPS, 1.0);
 
     if (closureData.closureType == CLOSURE_TYPE_REFLECTION)

libraries/pbrlib/genglsl/mx_chiang_hair_bsdf.glsl

@@ -193,7 +193,7 @@ void mx_chiang_hair_bsdf(ClosureData closureData, vec3 tint_R, vec3 tint_TT, vec
     vec3 V = closureData.V;
     vec3 L = closureData.L;
 
-    N = mx_forward_facing_normal(N, V);
+    N = mx_forward_facing_normal(N, closureData);
 
     bsdf.throughput = vec3(0.0);
 

libraries/pbrlib/genglsl/mx_conductor_bsdf.glsl

@@ -13,7 +13,7 @@ void mx_conductor_bsdf(ClosureData closureData, float weight, vec3 ior_n, vec3 i
     vec3 V = closureData.V;
     vec3 L = closureData.L;
 
-    N = mx_forward_facing_normal(N, V);
+    N = mx_forward_facing_normal(N, closureData);
     float NdotV = clamp(dot(N, V), M_FLOAT_EPS, 1.0);
 
     FresnelData fd = mx_init_fresnel_conductor(ior_n, ior_k, thinfilm_thickness, thinfilm_ior);

libraries/pbrlib/genglsl/mx_dielectric_bsdf.glsl

@@ -15,7 +15,7 @@ void mx_dielectric_bsdf(ClosureData closureData, float weight, vec3 tint, float
     vec3 V = closureData.V;
     vec3 L = closureData.L;
 
-    N = mx_forward_facing_normal(N, V);
+    N = mx_forward_facing_normal(N, closureData);
     float NdotV = clamp(dot(N, V), M_FLOAT_EPS, 1.0);
 
     FresnelData fd = mx_init_fresnel_dielectric(ior, thinfilm_thickness, thinfilm_ior);

libraries/pbrlib/genglsl/mx_generalized_schlick_bsdf.glsl

@@ -15,7 +15,7 @@ void mx_generalized_schlick_bsdf(ClosureData closureData, float weight, vec3 col
     vec3 V = closureData.V;
     vec3 L = closureData.L;
 
-    N = mx_forward_facing_normal(N, V);
+    N = mx_forward_facing_normal(N, closureData);
     float NdotV = clamp(dot(N, V), M_FLOAT_EPS, 1.0);
 
     vec3 safeColor0 = max(color0, 0.0);

libraries/pbrlib/genglsl/mx_generalized_schlick_edf.glsl

@@ -5,7 +5,7 @@ void mx_generalized_schlick_edf(ClosureData closureData, vec3 color0, vec3 color
 {
     if (closureData.closureType == CLOSURE_TYPE_EMISSION)
     {
-        vec3 N = mx_forward_facing_normal(closureData.N, closureData.V);
+        vec3 N = mx_forward_facing_normal(closureData.N, closureData);
         float NdotV = clamp(dot(N, closureData.V), M_FLOAT_EPS, 1.0);
         vec3 f = mx_fresnel_schlick(NdotV, color0, color90, exponent);
         result = base * f;

libraries/pbrlib/genglsl/mx_oren_nayar_diffuse_bsdf.glsl

@@ -13,7 +13,7 @@ void mx_oren_nayar_diffuse_bsdf(ClosureData closureData, float weight, vec3 colo
     vec3 V = closureData.V;
     vec3 L = closureData.L;
 
-    N = mx_forward_facing_normal(N, V);
+    N = mx_forward_facing_normal(N, closureData);
     float NdotV = clamp(dot(N, V), M_FLOAT_EPS, 1.0);
 
     if (closureData.closureType == CLOSURE_TYPE_REFLECTION)

libraries/pbrlib/genglsl/mx_sheen_bsdf.glsl

@@ -11,7 +11,7 @@ void mx_sheen_bsdf(ClosureData closureData, float weight, vec3 color, float roug
     vec3 V = closureData.V;
     vec3 L = closureData.L;
 
-    N = mx_forward_facing_normal(N, V);
+    N = mx_forward_facing_normal(N, closureData);
     float NdotV = clamp(dot(N, V), M_FLOAT_EPS, 1.0);
 
     float dirAlbedo;

libraries/pbrlib/genglsl/mx_subsurface_bsdf.glsl

@@ -15,7 +15,7 @@ void mx_subsurface_bsdf(ClosureData closureData, float weight, vec3 color, vec3
     vec3 P = closureData.P;
     float occlusion = closureData.occlusion;
 
-    N = mx_forward_facing_normal(N, V);
+    N = mx_forward_facing_normal(N, closureData);
 
     if (closureData.closureType == CLOSURE_TYPE_REFLECTION)
     {