EEVEE-Next: Make Specular BSDF work

This removes the ambient occlusion socket as this
have no use in EEVEE-Next.

Add correct material flags for noiseless clear coat
and fix transparency.

source/blender/draw/engines/eevee/shaders/closure_eval_surface_lib.glsl

@@ -225,8 +225,7 @@ Closure closure_eval(ClosureSubsurface diffuse, ClosureReflection reflection)
   /* Glue with the old system. */
   CLOSURE_VARS_DECLARE_2(Diffuse, Glossy);
 
-  /* WORKAROUND: This is to avoid regression in 3.2 and avoid messing with EEVEE-Next. */
-  in_common.occlusion = (diffuse.sss_radius.g == -1.0) ? diffuse.sss_radius.r : 1.0;
+  in_common.occlusion = 1.0;
   in_Diffuse_0.N = diffuse.N;
   in_Diffuse_0.albedo = diffuse.color;
   in_Glossy_1.N = reflection.N;
@@ -261,8 +260,7 @@ Closure closure_eval(ClosureSubsurface diffuse,
   /* Glue with the old system. */
   CLOSURE_VARS_DECLARE_3(Diffuse, Glossy, Glossy);
 
-  /* WORKAROUND: This is to avoid regression in 3.2 and avoid messing with EEVEE-Next. */
-  in_common.occlusion = (diffuse.sss_radius.g == -1.0) ? diffuse.sss_radius.r : 1.0;
+  in_common.occlusion = 1.0;
   in_Diffuse_0.N = diffuse.N;
   in_Diffuse_0.albedo = diffuse.color;
   in_Glossy_1.N = reflection.N;

source/blender/gpu/shaders/material/gpu_shader_material_eevee_specular.glsl

@@ -11,7 +11,6 @@ void node_eevee_specular(vec4 diffuse,
                          float clearcoat,
                          float clearcoat_roughness,
                          vec3 CN,
-                         float occlusion,
                          float weight,
                          const float use_clearcoat,
                          out Closure result)
@@ -24,7 +23,6 @@ void node_eevee_specular(vec4 diffuse,
   clearcoat = saturate(clearcoat);
   clearcoat_roughness = saturate(clearcoat_roughness);
   CN = safe_normalize(CN);
-  occlusion = saturate(occlusion);
 
   vec3 V = coordinate_incoming(g_data.P);
 
@@ -39,29 +37,11 @@ void node_eevee_specular(vec4 diffuse,
 
   float alpha = (1.0 - transp) * weight;
 
-#ifdef GPU_SHADER_EEVEE_LEGACY_DEFINES
-  /* EEVEE Legacy evaluates the subsurface as a diffuse closure.
-   * So this has no performance penalty. However, using a separate closure for subsurface
-   * (just like for EEVEE-Next) would induce a huge performance hit. */
-  ClosureSubsurface diffuse_data;
-  /* Disable subsurface. */
-  diffuse_data.sss_radius.b = -1.0;
-#else
   ClosureDiffuse diffuse_data;
-#endif
   diffuse_data.weight = alpha;
   diffuse_data.color = diffuse.rgb;
   diffuse_data.N = N;
 
-#ifdef GPU_SHADER_EEVEE_LEGACY_DEFINES
-  /* WORKAROUND: Nasty workaround to the current interface with the closure evaluation.
-   * Ideally the occlusion input should be move to the output node or removed all-together.
-   * This is temporary to avoid a regression in 3.2 and should be removed after EEVEE-Next rewrite.
-   */
-  diffuse_data.sss_radius.r = occlusion;
-  diffuse_data.sss_radius.g = -1.0; /* Flag */
-#endif
-
   ClosureReflection reflection_data;
   reflection_data.weight = alpha;
   if (true) {

source/blender/nodes/shader/nodes/node_shader_eevee_specular.cc

@@ -33,7 +33,6 @@ static void node_declare(NodeDeclarationBuilder &b)
       .max(1.0f)
       .subtype(PROP_FACTOR);
   b.add_input<decl::Vector>("Clear Coat Normal").hide_value();
-  b.add_input<decl::Float>("Ambient Occlusion").hide_value();
   b.add_input<decl::Float>("Weight").unavailable();
   b.add_output<decl::Shader>("BSDF");
 }
@@ -46,8 +45,6 @@ static int node_shader_gpu_eevee_specular(GPUMaterial *mat,
                                           GPUNodeStack *in,
                                           GPUNodeStack *out)
 {
-  static float one = 1.0f;
-
   /* Normals */
   if (!in[5].link) {
     GPU_link(mat, "world_normals_get", &in[5].link);
@@ -58,16 +55,21 @@ static int node_shader_gpu_eevee_specular(GPUMaterial *mat,
     GPU_link(mat, "world_normals_get", &in[8].link);
   }
 
-  /* Occlusion */
-  if (!in[9].link) {
-    GPU_link(mat, "set_value", GPU_constant(&one), &in[9].link);
+  bool use_transparency = socket_not_zero(4);
+  bool use_coat = socket_not_zero(6);
+
+  eGPUMaterialFlag flag = GPU_MATFLAG_DIFFUSE | GPU_MATFLAG_GLOSSY;
+  if (use_coat) {
+    flag |= GPU_MATFLAG_COAT;
+  }
+  if (use_transparency) {
+    flag |= GPU_MATFLAG_TRANSPARENT;
   }
 
-  GPU_material_flag_set(mat, GPU_MATFLAG_DIFFUSE | GPU_MATFLAG_GLOSSY);
+  GPU_material_flag_set(mat, flag);
 
-  float use_clear = socket_not_zero(6) ? 1.0f : 0.0f;
-
-  return GPU_stack_link(mat, node, "node_eevee_specular", in, out, GPU_constant(&use_clear));
+  float use_coat_f = use_coat ? 1.0f : 0.0f;
+  return GPU_stack_link(mat, node, "node_eevee_specular", in, out, GPU_constant(&use_coat_f));
 }
 
 }  // namespace blender::nodes::node_shader_eevee_specular_cc