Cycles: Refactor microfacet BSDFs to remove separate anisotropy code

Since the sampling and evaluation functions handle both cases anyways,
there's not really a point for keeping the distinction in the kernel,
so we might as well cut down the number of CLOSURE_BSDF_MICROFACETs a bit.

Differential Revision: https://developer.blender.org/D7736

4 files changed, 20 insertions, 92 deletions

diff --git a/intern/cycles/kernel/closure/bsdf.h b/intern/cycles/kernel/closure/bsdf.h
index 0a9631ad931..dc80e67a891 100644
--- a/intern/cycles/kernel/closure/bsdf.h
+++ b/intern/cycles/kernel/closure/bsdf.h
@@ -229,8 +229,6 @@ ccl_device_inline int bsdf_sample(KernelGlobals *kg,
     case CLOSURE_BSDF_MICROFACET_GGX_ID:
     case CLOSURE_BSDF_MICROFACET_GGX_FRESNEL_ID:
     case CLOSURE_BSDF_MICROFACET_GGX_CLEARCOAT_ID:
-    case CLOSURE_BSDF_MICROFACET_GGX_ANISO_ID:
-    case CLOSURE_BSDF_MICROFACET_GGX_ANISO_FRESNEL_ID:
     case CLOSURE_BSDF_MICROFACET_GGX_REFRACTION_ID:
       label = bsdf_microfacet_ggx_sample(kg,
                                          sc,
@@ -281,7 +279,6 @@ ccl_device_inline int bsdf_sample(KernelGlobals *kg,
                                                      &sd->lcg_state);
       break;
     case CLOSURE_BSDF_MICROFACET_BECKMANN_ID:
-    case CLOSURE_BSDF_MICROFACET_BECKMANN_ANISO_ID:
     case CLOSURE_BSDF_MICROFACET_BECKMANN_REFRACTION_ID:
       label = bsdf_microfacet_beckmann_sample(kg,
                                               sc,
@@ -298,7 +295,6 @@ ccl_device_inline int bsdf_sample(KernelGlobals *kg,
                                               pdf);
       break;
     case CLOSURE_BSDF_ASHIKHMIN_SHIRLEY_ID:
-    case CLOSURE_BSDF_ASHIKHMIN_SHIRLEY_ANISO_ID:
       label = bsdf_ashikhmin_shirley_sample(sc,
                                             sd->Ng,
                                             sd->I,
@@ -504,8 +500,6 @@ ccl_device_inline
       case CLOSURE_BSDF_MICROFACET_GGX_ID:
       case CLOSURE_BSDF_MICROFACET_GGX_FRESNEL_ID:
       case CLOSURE_BSDF_MICROFACET_GGX_CLEARCOAT_ID:
-      case CLOSURE_BSDF_MICROFACET_GGX_ANISO_ID:
-      case CLOSURE_BSDF_MICROFACET_GGX_ANISO_FRESNEL_ID:
       case CLOSURE_BSDF_MICROFACET_GGX_REFRACTION_ID:
         eval = bsdf_microfacet_ggx_eval_reflect(sc, sd->I, omega_in, pdf);
         break;
@@ -519,12 +513,10 @@ ccl_device_inline
             sc, sd->I, omega_in, pdf, &sd->lcg_state);
         break;
       case CLOSURE_BSDF_MICROFACET_BECKMANN_ID:
-      case CLOSURE_BSDF_MICROFACET_BECKMANN_ANISO_ID:
       case CLOSURE_BSDF_MICROFACET_BECKMANN_REFRACTION_ID:
         eval = bsdf_microfacet_beckmann_eval_reflect(sc, sd->I, omega_in, pdf);
         break;
       case CLOSURE_BSDF_ASHIKHMIN_SHIRLEY_ID:
-      case CLOSURE_BSDF_ASHIKHMIN_SHIRLEY_ANISO_ID:
         eval = bsdf_ashikhmin_shirley_eval_reflect(sc, sd->I, omega_in, pdf);
         break;
       case CLOSURE_BSDF_ASHIKHMIN_VELVET_ID:
@@ -595,8 +587,6 @@ ccl_device_inline
       case CLOSURE_BSDF_MICROFACET_GGX_ID:
       case CLOSURE_BSDF_MICROFACET_GGX_FRESNEL_ID:
       case CLOSURE_BSDF_MICROFACET_GGX_CLEARCOAT_ID:
-      case CLOSURE_BSDF_MICROFACET_GGX_ANISO_ID:
-      case CLOSURE_BSDF_MICROFACET_GGX_ANISO_FRESNEL_ID:
       case CLOSURE_BSDF_MICROFACET_GGX_REFRACTION_ID:
         eval = bsdf_microfacet_ggx_eval_transmit(sc, sd->I, omega_in, pdf);
         break;
@@ -610,12 +600,10 @@ ccl_device_inline
             sc, sd->I, omega_in, pdf, &sd->lcg_state);
         break;
       case CLOSURE_BSDF_MICROFACET_BECKMANN_ID:
-      case CLOSURE_BSDF_MICROFACET_BECKMANN_ANISO_ID:
       case CLOSURE_BSDF_MICROFACET_BECKMANN_REFRACTION_ID:
         eval = bsdf_microfacet_beckmann_eval_transmit(sc, sd->I, omega_in, pdf);
         break;
       case CLOSURE_BSDF_ASHIKHMIN_SHIRLEY_ID:
-      case CLOSURE_BSDF_ASHIKHMIN_SHIRLEY_ANISO_ID:
         eval = bsdf_ashikhmin_shirley_eval_transmit(sc, sd->I, omega_in, pdf);
         break;
       case CLOSURE_BSDF_ASHIKHMIN_VELVET_ID:
@@ -679,18 +667,14 @@ ccl_device void bsdf_blur(KernelGlobals *kg, ShaderClosure *sc, float roughness)
     case CLOSURE_BSDF_MICROFACET_GGX_ID:
     case CLOSURE_BSDF_MICROFACET_GGX_FRESNEL_ID:
     case CLOSURE_BSDF_MICROFACET_GGX_CLEARCOAT_ID:
-    case CLOSURE_BSDF_MICROFACET_GGX_ANISO_ID:
-    case CLOSURE_BSDF_MICROFACET_GGX_ANISO_FRESNEL_ID:
     case CLOSURE_BSDF_MICROFACET_GGX_REFRACTION_ID:
       bsdf_microfacet_ggx_blur(sc, roughness);
       break;
     case CLOSURE_BSDF_MICROFACET_BECKMANN_ID:
-    case CLOSURE_BSDF_MICROFACET_BECKMANN_ANISO_ID:
     case CLOSURE_BSDF_MICROFACET_BECKMANN_REFRACTION_ID:
       bsdf_microfacet_beckmann_blur(sc, roughness);
       break;
     case CLOSURE_BSDF_ASHIKHMIN_SHIRLEY_ID:
-    case CLOSURE_BSDF_ASHIKHMIN_SHIRLEY_ANISO_ID:
       bsdf_ashikhmin_shirley_blur(sc, roughness);
       break;
     case CLOSURE_BSDF_HAIR_PRINCIPLED_ID:
@@ -719,18 +703,14 @@ ccl_device bool bsdf_merge(ShaderClosure *a, ShaderClosure *b)
     case CLOSURE_BSDF_MICROFACET_GGX_ID:
     case CLOSURE_BSDF_MICROFACET_GGX_FRESNEL_ID:
     case CLOSURE_BSDF_MICROFACET_GGX_CLEARCOAT_ID:
-    case CLOSURE_BSDF_MICROFACET_GGX_ANISO_ID:
-    case CLOSURE_BSDF_MICROFACET_GGX_ANISO_FRESNEL_ID:
     case CLOSURE_BSDF_MICROFACET_GGX_REFRACTION_ID:
     case CLOSURE_BSDF_MICROFACET_MULTI_GGX_ID:
     case CLOSURE_BSDF_MICROFACET_MULTI_GGX_FRESNEL_ID:
     case CLOSURE_BSDF_MICROFACET_MULTI_GGX_GLASS_ID:
     case CLOSURE_BSDF_MICROFACET_MULTI_GGX_GLASS_FRESNEL_ID:
     case CLOSURE_BSDF_MICROFACET_BECKMANN_ID:
-    case CLOSURE_BSDF_MICROFACET_BECKMANN_ANISO_ID:
     case CLOSURE_BSDF_MICROFACET_BECKMANN_REFRACTION_ID:
     case CLOSURE_BSDF_ASHIKHMIN_SHIRLEY_ID:
-    case CLOSURE_BSDF_ASHIKHMIN_SHIRLEY_ANISO_ID:
       return bsdf_microfacet_merge(a, b);
     case CLOSURE_BSDF_ASHIKHMIN_VELVET_ID:
       return bsdf_ashikhmin_velvet_merge(a, b);
diff --git a/intern/cycles/kernel/closure/bsdf_ashikhmin_shirley.h b/intern/cycles/kernel/closure/bsdf_ashikhmin_shirley.h
index 6495ae743ab..0d50172a907 100644
--- a/intern/cycles/kernel/closure/bsdf_ashikhmin_shirley.h
+++ b/intern/cycles/kernel/closure/bsdf_ashikhmin_shirley.h
@@ -34,18 +34,9 @@ CCL_NAMESPACE_BEGIN
 ccl_device int bsdf_ashikhmin_shirley_setup(MicrofacetBsdf *bsdf)
 {
   bsdf->alpha_x = clamp(bsdf->alpha_x, 1e-4f, 1.0f);
-  bsdf->alpha_y = bsdf->alpha_x;
-
-  bsdf->type = CLOSURE_BSDF_ASHIKHMIN_SHIRLEY_ID;
-  return SD_BSDF | SD_BSDF_HAS_EVAL;
-}
-
-ccl_device int bsdf_ashikhmin_shirley_aniso_setup(MicrofacetBsdf *bsdf)
-{
-  bsdf->alpha_x = clamp(bsdf->alpha_x, 1e-4f, 1.0f);
   bsdf->alpha_y = clamp(bsdf->alpha_y, 1e-4f, 1.0f);
 
-  bsdf->type = CLOSURE_BSDF_ASHIKHMIN_SHIRLEY_ANISO_ID;
+  bsdf->type = CLOSURE_BSDF_ASHIKHMIN_SHIRLEY_ID;
   return SD_BSDF | SD_BSDF_HAS_EVAL;
 }
 
diff --git a/intern/cycles/kernel/closure/bsdf_microfacet.h b/intern/cycles/kernel/closure/bsdf_microfacet.h
index 2884ea62a18..d9e81535b62 100644
--- a/intern/cycles/kernel/closure/bsdf_microfacet.h
+++ b/intern/cycles/kernel/closure/bsdf_microfacet.h
@@ -256,9 +256,7 @@ ccl_device_forceinline float3 reflection_color(const MicrofacetBsdf *bsdf, float
 {
   float3 F = make_float3(1.0f, 1.0f, 1.0f);
   bool use_fresnel = (bsdf->type == CLOSURE_BSDF_MICROFACET_GGX_FRESNEL_ID ||
-                      bsdf->type == CLOSURE_BSDF_MICROFACET_GGX_CLEARCOAT_ID ||
-                      bsdf->type == CLOSURE_BSDF_MICROFACET_GGX_ANISO_FRESNEL_ID);
-
+                      bsdf->type == CLOSURE_BSDF_MICROFACET_GGX_CLEARCOAT_ID);
   if (use_fresnel) {
     float F0 = fresnel_dielectric_cos(1.0f, bsdf->ior);
 
@@ -311,19 +309,27 @@ ccl_device int bsdf_microfacet_ggx_setup(MicrofacetBsdf *bsdf)
   bsdf->extra = NULL;
 
   bsdf->alpha_x = saturate(bsdf->alpha_x);
-  bsdf->alpha_y = bsdf->alpha_x;
+  bsdf->alpha_y = saturate(bsdf->alpha_y);
 
   bsdf->type = CLOSURE_BSDF_MICROFACET_GGX_ID;
 
   return SD_BSDF | SD_BSDF_HAS_EVAL;
 }
 
+/* Required to maintain OSL interface. */
+ccl_device int bsdf_microfacet_ggx_isotropic_setup(MicrofacetBsdf *bsdf)
+{
+  bsdf->alpha_y = bsdf->alpha_x;
+
+  return bsdf_microfacet_ggx_setup(bsdf);
+}
+
 ccl_device int bsdf_microfacet_ggx_fresnel_setup(MicrofacetBsdf *bsdf, const ShaderData *sd)
 {
   bsdf->extra->cspec0 = saturate3(bsdf->extra->cspec0);
 
   bsdf->alpha_x = saturate(bsdf->alpha_x);
-  bsdf->alpha_y = bsdf->alpha_x;
+  bsdf->alpha_y = saturate(bsdf->alpha_y);
 
   bsdf->type = CLOSURE_BSDF_MICROFACET_GGX_FRESNEL_ID;
 
@@ -361,32 +367,6 @@ ccl_device bool bsdf_microfacet_merge(const ShaderClosure *a, const ShaderClosur
            (bsdf_a->extra->clearcoat == bsdf_b->extra->clearcoat)));
 }
 
-ccl_device int bsdf_microfacet_ggx_aniso_setup(MicrofacetBsdf *bsdf)
-{
-  bsdf->extra = NULL;
-
-  bsdf->alpha_x = saturate(bsdf->alpha_x);
-  bsdf->alpha_y = saturate(bsdf->alpha_y);
-
-  bsdf->type = CLOSURE_BSDF_MICROFACET_GGX_ANISO_ID;
-
-  return SD_BSDF | SD_BSDF_HAS_EVAL;
-}
-
-ccl_device int bsdf_microfacet_ggx_aniso_fresnel_setup(MicrofacetBsdf *bsdf, const ShaderData *sd)
-{
-  bsdf->extra->cspec0 = saturate3(bsdf->extra->cspec0);
-
-  bsdf->alpha_x = saturate(bsdf->alpha_x);
-  bsdf->alpha_y = saturate(bsdf->alpha_y);
-
-  bsdf->type = CLOSURE_BSDF_MICROFACET_GGX_ANISO_FRESNEL_ID;
-
-  bsdf_microfacet_fresnel_color(sd, bsdf);
-
-  return SD_BSDF | SD_BSDF_HAS_EVAL;
-}
-
 ccl_device int bsdf_microfacet_ggx_refraction_setup(MicrofacetBsdf *bsdf)
 {
   bsdf->extra = NULL;
@@ -636,8 +616,7 @@ ccl_device int bsdf_microfacet_ggx_sample(KernelGlobals *kg,
             *eval = make_float3(1e6f, 1e6f, 1e6f);
 
             bool use_fresnel = (bsdf->type == CLOSURE_BSDF_MICROFACET_GGX_FRESNEL_ID ||
-                                bsdf->type == CLOSURE_BSDF_MICROFACET_GGX_CLEARCOAT_ID ||
-                                bsdf->type == CLOSURE_BSDF_MICROFACET_GGX_ANISO_FRESNEL_ID);
+                                bsdf->type == CLOSURE_BSDF_MICROFACET_GGX_CLEARCOAT_ID);
 
             /* if fresnel is used, calculate the color with reflection_color(...) */
             if (use_fresnel) {
@@ -811,19 +790,18 @@ ccl_device int bsdf_microfacet_ggx_sample(KernelGlobals *kg,
 ccl_device int bsdf_microfacet_beckmann_setup(MicrofacetBsdf *bsdf)
 {
   bsdf->alpha_x = saturate(bsdf->alpha_x);
-  bsdf->alpha_y = bsdf->alpha_x;
+  bsdf->alpha_y = saturate(bsdf->alpha_y);
 
   bsdf->type = CLOSURE_BSDF_MICROFACET_BECKMANN_ID;
   return SD_BSDF | SD_BSDF_HAS_EVAL;
 }
 
-ccl_device int bsdf_microfacet_beckmann_aniso_setup(MicrofacetBsdf *bsdf)
+/* Required to maintain OSL interface. */
+ccl_device int bsdf_microfacet_beckmann_isotropic_setup(MicrofacetBsdf *bsdf)
 {
-  bsdf->alpha_x = saturate(bsdf->alpha_x);
-  bsdf->alpha_y = saturate(bsdf->alpha_y);
+  bsdf->alpha_y = bsdf->alpha_x;
 
-  bsdf->type = CLOSURE_BSDF_MICROFACET_BECKMANN_ANISO_ID;
-  return SD_BSDF | SD_BSDF_HAS_EVAL;
+  return bsdf_microfacet_beckmann_setup(bsdf);
 }
 
 ccl_device int bsdf_microfacet_beckmann_refraction_setup(MicrofacetBsdf *bsdf)
diff --git a/intern/cycles/kernel/closure/bsdf_microfacet_multi.h b/intern/cycles/kernel/closure/bsdf_microfacet_multi.h
index a5fe989bcd1..9795c8da065 100644
--- a/intern/cycles/kernel/closure/bsdf_microfacet_multi.h
+++ b/intern/cycles/kernel/closure/bsdf_microfacet_multi.h
@@ -384,7 +384,7 @@ ccl_device int bsdf_microfacet_multi_ggx_common_setup(MicrofacetBsdf *bsdf)
   return SD_BSDF | SD_BSDF_HAS_EVAL | SD_BSDF_NEEDS_LCG;
 }
 
-ccl_device int bsdf_microfacet_multi_ggx_aniso_setup(MicrofacetBsdf *bsdf)
+ccl_device int bsdf_microfacet_multi_ggx_setup(MicrofacetBsdf *bsdf)
 {
   if (is_zero(bsdf->T))
     bsdf->T = make_float3(1.0f, 0.0f, 0.0f);
@@ -394,8 +394,7 @@ ccl_device int bsdf_microfacet_multi_ggx_aniso_setup(MicrofacetBsdf *bsdf)
   return bsdf_microfacet_multi_ggx_common_setup(bsdf);
 }
 
-ccl_device int bsdf_microfacet_multi_ggx_aniso_fresnel_setup(MicrofacetBsdf *bsdf,
-                                                             const ShaderData *sd)
+ccl_device int bsdf_microfacet_multi_ggx_fresnel_setup(MicrofacetBsdf *bsdf, const ShaderData *sd)
 {
   if (is_zero(bsdf->T))
     bsdf->T = make_float3(1.0f, 0.0f, 0.0f);
@@ -407,26 +406,6 @@ ccl_device int bsdf_microfacet_multi_ggx_aniso_fresnel_setup(MicrofacetBsdf *bsd
   return bsdf_microfacet_multi_ggx_common_setup(bsdf);
 }
 
-ccl_device int bsdf_microfacet_multi_ggx_setup(MicrofacetBsdf *bsdf)
-{
-  bsdf->alpha_y = bsdf->alpha_x;
-
-  bsdf->type = CLOSURE_BSDF_MICROFACET_MULTI_GGX_ID;
-
-  return bsdf_microfacet_multi_ggx_common_setup(bsdf);
-}
-
-ccl_device int bsdf_microfacet_multi_ggx_fresnel_setup(MicrofacetBsdf *bsdf, const ShaderData *sd)
-{
-  bsdf->alpha_y = bsdf->alpha_x;
-
-  bsdf->type = CLOSURE_BSDF_MICROFACET_MULTI_GGX_FRESNEL_ID;
-
-  bsdf_microfacet_fresnel_color(sd, bsdf);
-
-  return bsdf_microfacet_multi_ggx_common_setup(bsdf);
-}
-
 ccl_device int bsdf_microfacet_multi_ggx_refraction_setup(MicrofacetBsdf *bsdf)
 {
   bsdf->alpha_y = bsdf->alpha_x;