intern/cycles/kernel/closure/bsdf_hair_microfacet.h

@@ -15,15 +15,11 @@
 
 CCL_NAMESPACE_BEGIN
 
-typedef struct MicrofacetHairExtra {
-  /* TODO: is this necessary? */
+typedef struct MicrofacetHairLobeFactor {
   float R;
   float TT;
   float TRT;
-
-  /* Geometry data. */
-  float4 geom;
-} MicrofacetHairExtra;
+} MicrofacetHairLobeFactor;
 
 typedef struct MicrofacetHairBSDF {
   SHADER_CLOSURE_BASE;
@@ -43,14 +39,17 @@ typedef struct MicrofacetHairBSDF {
   /* The ratio of the minor axis to the major axis. */
   float aspect_ratio;
 
-  /* Extra closure. */
-  ccl_private MicrofacetHairExtra *extra;
+  /* Azimuthal offset. */
+  float h;
+
+  /* Extra closure for optional modulation factors. */
+  ccl_private MicrofacetHairLobeFactor *factor;
 } MicrofacetHairBSDF;
 
 static_assert(sizeof(ShaderClosure) >= sizeof(MicrofacetHairBSDF),
               "MicrofacetHairBSDF is too large!");
-static_assert(sizeof(ShaderClosure) >= sizeof(MicrofacetHairExtra),
-              "MicrofacetHairExtra is too large!");
+static_assert(sizeof(ShaderClosure) >= sizeof(MicrofacetHairLobeFactor),
+              "MicrofacetHairLobeFactor is too large!");
 
 #ifdef __HAIR__
 /* Set up the hair closure. */
@@ -69,32 +68,27 @@ ccl_device int bsdf_microfacet_hair_setup(ccl_private ShaderData *sd,
 
   /* h -1..0..1 means the rays goes from grazing the hair, to hitting it at the center, to grazing
    * the other edge. This is the cosine of the angle between sd->N and X. */
-  const float h = (sd->type & PRIMITIVE_CURVE_RIBBON) ? -sd->v : -dot(X, sd->N);
+  bsdf->h = (sd->type & PRIMITIVE_CURVE_RIBBON) ? -sd->v : -dot(X, sd->N);
 
-  kernel_assert(fabsf(h) < 1.0f + 1e-4f);
-  kernel_assert(isfinite_safe(X));
-  kernel_assert(isfinite_safe(h));
+  kernel_assert(fabsf(bsdf->h) < 1.0f + 1e-4f);
+  kernel_assert(isfinite_safe(bsdf->h));
 
   if (bsdf->aspect_ratio != 1.0f && !(sd->type & PRIMITIVE_TRIANGLE)) {
     if (bsdf->aspect_ratio > 1.0f) {
       bsdf->aspect_ratio = 1.0f / bsdf->aspect_ratio;
 
       /* Switch major and minor axis. */
-      const float3 minor_axis = safe_normalize(cross(
-          sd->dPdu, make_float3(bsdf->extra->geom.x, bsdf->extra->geom.y, bsdf->extra->geom.z)));
-      const float3 major_axis = safe_normalize(cross(minor_axis, sd->dPdu));
-
-      bsdf->extra->geom = make_float4(major_axis.x, major_axis.y, major_axis.z, h);
-    }
-    else {
-      bsdf->extra->geom.w = h;
+      const float3 minor_axis = safe_normalize(cross(sd->dPdu, bsdf->N));
+      bsdf->N = safe_normalize(cross(minor_axis, sd->dPdu));
     }
   }
   else {
     /* Align local frame with the ray direction so that `phi_i == 0`. */
-    bsdf->extra->geom = make_float4(X.x, X.y, X.z, h);
+    bsdf->N = X;
   }
 
+  kernel_assert(!is_zero(bsdf->N) && isfinite_safe(bsdf->N));
+
   return SD_BSDF | SD_BSDF_HAS_EVAL | SD_BSDF_NEEDS_LCG | SD_BSDF_HAS_TRANSMISSION;
 }
 
@@ -310,7 +304,7 @@ ccl_device float3 bsdf_microfacet_hair_eval_r(ccl_private const ShaderClosure *s
   const float roughness2 = sqr(roughness);
   const float eta = bsdf->eta;
 
-  if (bsdf->extra->R <= 0.0f) {
+  if (bsdf->factor->R <= 0.0f) {
     return zero_float3();
   }
 
@@ -389,7 +383,7 @@ ccl_device float3 bsdf_microfacet_hair_eval_r(ccl_private const ShaderClosure *s
 
   const float F = fresnel_dielectric_cos(dot(wi, wh), eta);
 
-  return make_float3(bsdf->extra->R * 0.125f * F * integral / projected_radius(e2, sinf(phi_i)));
+  return make_float3(bsdf->factor->R * 0.125f * F * integral / projected_radius(e2, sinf(phi_i)));
 }
 
 template<MicrofacetType m_type>
@@ -405,7 +399,7 @@ ccl_device float3 bsdf_microfacet_hair_eval_tt_trt(KernelGlobals kg,
   const float roughness2 = sqr(roughness);
   const float eta = bsdf->eta;
 
-  if (bsdf->extra->TT <= 0.0f && bsdf->extra->TRT <= 0.0f) {
+  if (bsdf->factor->TT <= 0.0f && bsdf->factor->TRT <= 0.0f) {
     return zero_float3();
   }
 
@@ -487,7 +481,7 @@ ccl_device float3 bsdf_microfacet_hair_eval_tt_trt(KernelGlobals kg,
                                 -len(to_point(gamma_mi, b) - to_point(gamma_mt + M_PI_F, b))));
 
     /* TT */
-    if (bsdf->extra->TT > 0.0f) {
+    if (bsdf->factor->TT > 0.0f) {
       if (dot(wo, wt) >= inv_eta - 1e-5f) { /* Total internal reflection otherwise. */
         float3 wh2 = -wt + inv_eta * wo;
         const float rcp_norm_wh2 = 1.0f / len(wh2);
@@ -507,14 +501,14 @@ ccl_device float3 bsdf_microfacet_hair_eval_tt_trt(KernelGlobals kg,
                                 cos_hi2 * cos_ho2 * sqr(rcp_norm_wh2);
 
           if (isfinite_safe(result)) {
-            S_tt += bsdf->extra->TT * result * arc_length(e2, gamma_mt);
+            S_tt += bsdf->factor->TT * result * arc_length(e2, gamma_mt);
           }
         }
       }
     }
 
     /* TRT */
-    if (bsdf->extra->TRT > 0.0f) {
+    if (bsdf->factor->TRT > 0.0f) {
       /* Sample wh2. */
       const float2 sample2 = make_float2(lcg_step_float(&rng_quadrature),
                                          lcg_step_float(&rng_quadrature));
@@ -570,7 +564,7 @@ ccl_device float3 bsdf_microfacet_hair_eval_tt_trt(KernelGlobals kg,
                             sqr(rcp_norm_wh3);
 
       if (isfinite_safe(result)) {
-        S_trt += bsdf->extra->TRT * result * arc_length(e2, gamma_mtr);
+        S_trt += bsdf->factor->TRT * result * arc_length(e2, gamma_mtr);
       }
     }
   }
@@ -595,7 +589,7 @@ ccl_device int bsdf_microfacet_hair_sample(const KernelGlobals kg,
   *eta = bsdf->eta;
   const float inv_eta = 1.0f / *eta;
 
-  if (bsdf->extra->R <= 0.0f && bsdf->extra->TT <= 0.0f && bsdf->extra->TRT <= 0.0f) {
+  if (bsdf->factor->R <= 0.0f && bsdf->factor->TT <= 0.0f && bsdf->factor->TRT <= 0.0f) {
     /* Early out for inactive lobe. */
     *pdf = 0.0f;
     return LABEL_NONE;
@@ -605,7 +599,7 @@ ccl_device int bsdf_microfacet_hair_sample(const KernelGlobals kg,
    * . X major axis.
    * . Y along the fiber tangent.
    * . Z minor axis. */
-  const float3 X = float4_to_float3(bsdf->extra->geom);
+  const float3 X = bsdf->N;
   const float3 Z = safe_normalize(cross(X, sd->dPdu));
   const float3 Y = safe_normalize(cross(Z, X));
 
@@ -624,7 +618,7 @@ ccl_device int bsdf_microfacet_hair_sample(const KernelGlobals kg,
   const float d_i = projected_radius(e2, sin_phi_i);
 
   /* Treat as transparent material if intersection lies outside of the projected radius. */
-  if (fabsf(bsdf->extra->geom.w) > d_i) {
+  if (fabsf(bsdf->h) > d_i) {
     *wo = -sd->wi;
     *pdf = 1;
     *eval = one_spectrum();
@@ -675,7 +669,7 @@ ccl_device int bsdf_microfacet_hair_sample(const KernelGlobals kg,
 
   float cos_theta_t1;
   const float R1 = fresnel(dot(wi, wh1), *eta, &cos_theta_t1);
-  const float3 R = make_float3(bsdf->extra->R * R1);
+  const float3 R = make_float3(bsdf->factor->R * R1);
 
   /* Sample TT lobe. */
   const float3 wt = -refract_angle(wi, wh1, cos_theta_t1, inv_eta);
@@ -710,7 +704,7 @@ ccl_device int bsdf_microfacet_hair_sample(const KernelGlobals kg,
     wtt = -refract_angle(-wt, wh2, cos_theta_t2, *eta);
 
     if (dot(wmt, -wtt) > 0.0f && cos_theta_t2 != 0.0f) {
-      TT = bsdf->extra->TT * T1 * A_t * T2;
+      TT = bsdf->factor->TT * T1 * A_t * T2;
     }
 
     /* Sample TRT lobe. */
@@ -735,7 +729,7 @@ ccl_device int bsdf_microfacet_hair_sample(const KernelGlobals kg,
                                    2.0f * cos(phi_tr - gamma_mt) :
                                    -len(to_point(gamma_mt, b) - to_point(gamma_mtr, b))));
 
-      TRT = bsdf->extra->TRT * T1 * R2 * T3 * A_t * A_tr;
+      TRT = bsdf->factor->TRT * T1 * R2 * T3 * A_t * A_tr;
     }
   }
 
@@ -815,7 +809,7 @@ ccl_device Spectrum bsdf_microfacet_hair_eval(KernelGlobals kg,
    * . X major axis.
    * . Y along the fiber tangent.
    * . Z minor axis. */
-  const float3 X = float4_to_float3(bsdf->extra->geom);
+  const float3 X = bsdf->N;
   const float3 Z = safe_normalize(cross(X, sd->dPdu));
   const float3 Y = safe_normalize(cross(Z, X));
 
@@ -825,7 +819,7 @@ ccl_device Spectrum bsdf_microfacet_hair_eval(KernelGlobals kg,
 
   /* Treat as transparent material if intersection lies outside of the projected radius. */
   const float e2 = 1.0f - sqr(bsdf->aspect_ratio);
-  if (fabsf(bsdf->extra->geom.w) > projected_radius(e2, sin_phi(local_I))) {
+  if (fabsf(bsdf->h) > projected_radius(e2, sin_phi(local_I))) {
     *pdf = 0.0f;
     return zero_spectrum();
   }

intern/cycles/kernel/osl/closures_setup.h

@@ -1300,13 +1300,13 @@ ccl_device void osl_closure_microfacet_hair_setup(KernelGlobals kg,
     return;
   }
 
-  ccl_private MicrofacetHairExtra *extra = (ccl_private MicrofacetHairExtra *)closure_alloc_extra(
-      sd, sizeof(MicrofacetHairExtra));
-  if (!extra) {
+  ccl_private MicrofacetHairLobeFactor *factor = (ccl_private MicrofacetHairLobeFactor *)
+      closure_alloc_extra(sd, sizeof(MicrofacetHairLobeFactor));
+  if (!factor) {
     return;
   }
 
-  bsdf->N = ensure_valid_specular_reflection(sd->Ng, sd->wi, closure->N);
+  bsdf->N = closure->N;
   bsdf->sigma = closure->sigma;
   bsdf->roughness = closure->roughness;
   bsdf->tilt = closure->tilt;
@@ -1314,12 +1314,10 @@ ccl_device void osl_closure_microfacet_hair_setup(KernelGlobals kg,
   bsdf->distribution_type = closure->distribution_type;
   bsdf->aspect_ratio = closure->aspect_ratio;
 
-  bsdf->extra = extra;
-  bsdf->extra->R = closure->reflection;
-  bsdf->extra->TT = closure->transmission;
-  bsdf->extra->TRT = closure->secondary_reflection;
-  bsdf->extra->geom = make_float4(
-      closure->major_axis.x, closure->major_axis.y, closure->major_axis.z, 0.0f);
+  bsdf->factor = factor;
+  bsdf->factor->R = closure->reflection;
+  bsdf->factor->TT = closure->transmission;
+  bsdf->factor->TRT = closure->secondary_reflection;
 
   sd->flag |= bsdf_microfacet_hair_setup(sd, bsdf);
 #endif

intern/cycles/kernel/osl/closures_template.h

@@ -290,7 +290,6 @@ OSL_CLOSURE_STRUCT_BEGIN(MicrofacetHair, microfacet_hair)
   OSL_CLOSURE_STRUCT_MEMBER(MicrofacetHair, FLOAT, float, reflection, NULL)
   OSL_CLOSURE_STRUCT_MEMBER(MicrofacetHair, FLOAT, float, transmission, NULL)
   OSL_CLOSURE_STRUCT_MEMBER(MicrofacetHair, FLOAT, float, secondary_reflection, NULL)
-  OSL_CLOSURE_STRUCT_MEMBER(MicrofacetHair, VECTOR, packed_float3, major_axis, NULL)
 OSL_CLOSURE_STRUCT_END(MicrofacetHair, microfacet_hair)
 
 OSL_CLOSURE_STRUCT_BEGIN(VolumeAbsorption, absorption)

intern/cycles/kernel/osl/shaders/node_microfacet_hair_bsdf.osl

@@ -41,7 +41,6 @@ shader node_microfacet_hair_bsdf(color Color = color(0.017513, 0.005763, 0.00205
                                  float RandomColor = 0.0,
                                  color Tint = 1.0,
                                  color AbsorptionCoefficient = color(0.245531, 0.52, 1.365),
-                                 normal Normal = Ng,
                                  string parametrization = "Direct Coloring",
                                  string distribution_type = "GGX",
                                  float Offset = radians(2),
@@ -103,13 +102,13 @@ shader node_microfacet_hair_bsdf(color Color = color(0.017513, 0.005763, 0.00205
   }
 
   int distribution_type_enum = (distribution_type == "GGX") ? 0 : 1;
-  normal major_axis = 0.0;
 
+  normal major_axis = 0.0;
   if (AspectRatio != 1.0) {
     getattribute("geom:N", major_axis);
   }
 
-  BSDF = microfacet_hair(Normal,
+  BSDF = microfacet_hair(major_axis,
                          sigma,
                          roughness,
                          Offset,
@@ -118,6 +117,5 @@ shader node_microfacet_hair_bsdf(color Color = color(0.017513, 0.005763, 0.00205
                          AspectRatio,
                          Reflection,
                          Transmission,
-                         SecondaryReflection,
-                         major_axis);
+                         SecondaryReflection);
 }

intern/cycles/kernel/osl/shaders/stdcycles.h

@@ -69,8 +69,7 @@ closure color microfacet_hair(normal N,
                               float aspect_ratio,
                               float reflection,
                               float transmission,
-                              float secondary_reflection,
-                              normal major_axis) BUILTIN;
+                              float secondary_reflection) BUILTIN;
 
 // Volume
 closure color henyey_greenstein(float g) BUILTIN;

intern/cycles/kernel/svm/closure.h

@@ -848,26 +848,24 @@ ccl_device_noinline int svm_node_closure_bsdf(KernelGlobals kg,
       ccl_private MicrofacetHairBSDF *bsdf = (ccl_private MicrofacetHairBSDF *)bsdf_alloc(
           sd, sizeof(MicrofacetHairBSDF), weight);
       if (bsdf) {
-        ccl_private MicrofacetHairExtra *extra = (ccl_private MicrofacetHairExtra *)
-            closure_alloc_extra(sd, sizeof(MicrofacetHairExtra));
+        ccl_private MicrofacetHairLobeFactor *factor = (ccl_private MicrofacetHairLobeFactor *)
+            closure_alloc_extra(sd, sizeof(MicrofacetHairLobeFactor));
 
-        if (!extra) {
+        if (!factor) {
           break;
         }
 
-        bsdf->extra = extra;
-        bsdf->extra->R = fmaxf(0.0f, R);
-        bsdf->extra->TT = fmaxf(0.0f, TT);
-        bsdf->extra->TRT = fmaxf(0.0f, TRT);
+        bsdf->factor = factor;
+        bsdf->factor->R = fmaxf(0.0f, R);
+        bsdf->factor->TT = fmaxf(0.0f, TT);
+        bsdf->factor->TRT = fmaxf(0.0f, TRT);
 
         bsdf->aspect_ratio = stack_load_float_default(stack, aspect_ratio_ofs, data_node2.y);
 
         if (bsdf->aspect_ratio != 1.0f) {
-          const AttributeDescriptor attr_descr_normal = find_attribute(kg, sd, attr_normal);
-          const float3 major_axis = curve_attribute_float3(kg, sd, attr_descr_normal, NULL, NULL);
-
           /* Align ellipse major axis with the curve normal direction. */
-          bsdf->extra->geom = make_float4(major_axis.x, major_axis.y, major_axis.z, 0.0f);
+          const AttributeDescriptor attr_descr_normal = find_attribute(kg, sd, attr_normal);
+          bsdf->N = curve_attribute_float3(kg, sd, attr_descr_normal, NULL, NULL);
         }
 
         /* Random factors range: [-randomization/2, +randomization/2]. */
@@ -878,7 +876,6 @@ ccl_device_noinline int svm_node_closure_bsdf(KernelGlobals kg,
         bsdf->distribution_type = clamp(
             distribution_type, NODE_MICROFACET_HAIR_GGX, NODE_MICROFACET_HAIR_BECKMANN);
 
-        bsdf->N = N;
         bsdf->roughness = roughness;
         bsdf->tilt = tilt;
         bsdf->eta = ior;