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

@@ -119,6 +119,22 @@ Closure closure_eval(ClosureReflection reflection)
   return closure;
 }
 
+CLOSURE_EVAL_FUNCTION_DECLARE_1(GlossyBSDFAlways, Glossy)
+Closure closure_eval_always(ClosureReflection reflection)
+{
+  /* Glue with the old system. */
+  CLOSURE_VARS_DECLARE_1(Glossy);
+
+  in_Glossy_0.N = reflection.N;
+  in_Glossy_0.roughness = reflection.roughness;
+
+  CLOSURE_EVAL_FUNCTION_1(GlossyBSDF, Glossy);
+
+  Closure closure = CLOSURE_DEFAULT;
+  closure.radiance += out_Glossy_0.radiance * reflection.color * reflection.weight;
+  return closure;
+}
+
 CLOSURE_EVAL_FUNCTION_DECLARE_1(RefractionBSDF, Refraction)
 Closure closure_eval(ClosureRefraction refraction)
 {
@@ -155,6 +171,13 @@ Closure closure_eval(ClosureTransparency transparency)
 CLOSURE_EVAL_FUNCTION_DECLARE_2(GlassBSDF, Glossy, Refraction)
 Closure closure_eval(ClosureReflection reflection, ClosureRefraction refraction)
 {
+
+#if defined(DO_SPLIT_CLOSURE_EVAL)
+  Closure closure = closure_eval(refraction);
+  Closure closure_reflection = closure_eval(reflection);
+  closure.radiance += closure_reflection.radiance;
+  return closure;
+#else
   /* Glue with the old system. */
   CLOSURE_VARS_DECLARE_2(Glossy, Refraction);
 
@@ -172,12 +195,19 @@ Closure closure_eval(ClosureReflection reflection, ClosureRefraction refraction)
     closure.radiance += out_Glossy_0.radiance * reflection.color * reflection.weight;
   }
   return closure;
+#endif
 }
 
 /* Dielectric BSDF */
 CLOSURE_EVAL_FUNCTION_DECLARE_2(DielectricBSDF, Diffuse, Glossy)
 Closure closure_eval(ClosureDiffuse diffuse, ClosureReflection reflection)
 {
+#if defined(DO_SPLIT_CLOSURE_EVAL)
+  Closure closure = closure_eval(diffuse);
+  Closure closure_reflection = closure_eval(reflection);
+  closure.radiance += closure_reflection.radiance;
+  return closure;
+#else
   /* Glue with the old system. */
   CLOSURE_VARS_DECLARE_2(Diffuse, Glossy);
 
@@ -198,6 +228,7 @@ Closure closure_eval(ClosureDiffuse diffuse, ClosureReflection reflection)
     closure.radiance += out_Glossy_1.radiance * reflection.color * reflection.weight;
   }
   return closure;
+#endif
 }
 
 /* Specular BSDF */
@@ -206,6 +237,13 @@ Closure closure_eval(ClosureDiffuse diffuse,
                      ClosureReflection reflection,
                      ClosureReflection clearcoat)
 {
+#if defined(DO_SPLIT_CLOSURE_EVAL)
+  Closure closure = closure_eval(diffuse);
+  Closure closure_reflection = closure_eval(reflection);
+  Closure closure_clearcoat = closure_eval_always(clearcoat);
+  closure.radiance += closure_reflection.radiance + closure_clearcoat.radiance;
+  return closure;
+#else
   /* Glue with the old system. */
   CLOSURE_VARS_DECLARE_3(Diffuse, Glossy, Glossy);
 
@@ -229,6 +267,7 @@ Closure closure_eval(ClosureDiffuse diffuse,
     closure.radiance += out_Glossy_1.radiance * reflection.color * reflection.weight;
   }
   return closure;
+#endif
 }
 
 /* Principled BSDF */
@@ -238,6 +277,15 @@ Closure closure_eval(ClosureDiffuse diffuse,
                      ClosureReflection clearcoat,
                      ClosureRefraction refraction)
 {
+#if defined(DO_SPLIT_CLOSURE_EVAL)
+  Closure closure = closure_eval(diffuse);
+  Closure closure_reflection = closure_eval(reflection);
+  Closure closure_clearcoat = closure_eval_always(clearcoat);
+  Closure closure_refraction = closure_eval(refraction);
+  closure.radiance += closure_reflection.radiance + closure_clearcoat.radiance +
+                      closure_refraction.radiance;
+  return closure;
+#else
   /* Glue with the old system. */
   CLOSURE_VARS_DECLARE_4(Diffuse, Glossy, Glossy, Refraction);
 
@@ -263,11 +311,18 @@ Closure closure_eval(ClosureDiffuse diffuse,
     closure.radiance += out_Glossy_1.radiance * reflection.color * reflection.weight;
   }
   return closure;
+#endif
 }
 
 CLOSURE_EVAL_FUNCTION_DECLARE_2(PrincipledBSDFMetalClearCoat, Glossy, Glossy)
 Closure closure_eval(ClosureReflection reflection, ClosureReflection clearcoat)
 {
+#if defined(DO_SPLIT_CLOSURE_EVAL)
+  Closure closure = closure_eval(clearcoat);
+  Closure closure_reflection = closure_eval(reflection);
+  closure.radiance += closure_reflection.radiance;
+  return closure;
+#else
   /* Glue with the old system. */
   CLOSURE_VARS_DECLARE_2(Glossy, Glossy);
 
@@ -284,6 +339,7 @@ Closure closure_eval(ClosureReflection reflection, ClosureReflection clearcoat)
     closure.radiance += out_Glossy_0.radiance * reflection.color * reflection.weight;
   }
   return closure;
+#endif
 }
 
 /* Not supported for surface shaders. */

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

@@ -17,6 +17,10 @@ Closure closure_eval(ClosureReflection reflection)
 {
   return CLOSURE_DEFAULT;
 }
+Closure closure_eval_always(ClosureReflection reflection)
+{
+  return CLOSURE_DEFAULT;
+}
 Closure closure_eval(ClosureRefraction refraction)
 {
   return CLOSURE_DEFAULT;

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

@@ -53,6 +53,7 @@ vec3 coordinate_incoming(vec3 P);
 Closure closure_eval(ClosureDiffuse diffuse);
 Closure closure_eval(ClosureTranslucent translucent);
 Closure closure_eval(ClosureReflection reflection);
+Closure closure_eval_always(ClosureReflection reflection);
 Closure closure_eval(ClosureRefraction refraction);
 Closure closure_eval(ClosureEmission emission);
 Closure closure_eval(ClosureTransparency transparency);

source/blender/draw/engines/eevee/shaders/infos/engine_eevee_legacy_shared.h

@@ -16,6 +16,14 @@ typedef struct CommonUniformBlock CommonUniformBlock;
 #  endif
 #endif
 
+/* NOTE: AMD-based macOS platforms experience performance and correctness issues with EEVEE
+ * material closure evaluation. Using singular closure evaluation, rather than the compound
+ * function calls reduces register overflow, by limiting the simultaneous number of live
+ * registers used by the virtual GPU function stack. */
+#if (defined(GPU_METAL) && defined(GPU_ATI))
+#  define DO_SPLIT_CLOSURE_EVAL 1
+#endif
+
 struct CommonUniformBlock {
   mat4 pastViewProjectionMatrix;
   vec4 hizUvScale; /* To correct mip level texel misalignment */

source/blender/draw/engines/eevee_next/shaders/eevee_nodetree_lib.glsl

@@ -92,6 +92,12 @@ Closure closure_eval(ClosureReflection reflection)
   return Closure(0);
 }
 
+Closure closure_eval_always(ClosureReflection reflection)
+{
+  SELECT_CLOSURE(g_reflection_data, g_reflection_rand, reflection);
+  return Closure(0);
+}
+
 Closure closure_eval(ClosureRefraction refraction)
 {
   SELECT_CLOSURE(g_refraction_data, g_refraction_rand, refraction);