Fix Cycles OSL potentially skipping closures when using layering

Pull Request: #112213

@@ -692,6 +692,13 @@ static void version_principled_bsdf_emission(bNodeTree *ntree)
   }
 }
 
+/* Rename Principled BSDF emission to emission color. */

@@ -337,0 +341,4 @@
+}
+
+/* Simplified form of F_eta(eta, 1.0). */
+float F0_from_ior(float eta)

@@ -112,0 +111,4 @@
+      .subtype(PROP_FACTOR)
+      .description(
+          "Adjustment to the IOR to increase or decrease specular intensity "
+          "(0.5 means no adjustment, 0 removes all reflections, 1 doubles them)");

@@ -118,0 +116,4 @@
+  spec.add_input<decl::Color>("Specular Tint")
+      .default_value({1.0f, 1.0f, 1.0f, 1.0f})
+      .description(
+          "Tint of the specular reflection at normal incidence. Affects dielectric materials");

@@ -105,3 +105,1 @@
-      float specular_tint = stack_load_float(stack, specular_tint_offset);
-      float anisotropic = stack_load_float(stack, anisotropic_offset);
-      float sheen = stack_load_float(stack, sheen_offset);
+      float subsurface_weight = param2;

@@ -108,0 +106,4 @@
+      float specular_ior_level = fmaxf(stack_load_float(stack, specular_ior_level_offset), 0.0f);
+      float roughness = saturatef(stack_load_float(stack, roughness_offset));
+      Spectrum specular_tint = rgb_to_spectrum(
+          saturate(stack_load_float3(stack, specular_tint_offset)));

@@ -55,9 +61,21 @@ void node_bsdf_principled(vec4 base_color,
 {

@@ -55,9 +61,21 @@ void node_bsdf_principled(vec4 base_color,
 {
   /* Match cycles. */
   metallic = clamp(metallic, 0.0, 1.0);