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

@@ -16,8 +16,16 @@ void node_eevee_specular(vec4 diffuse,
                          const float use_clearcoat,
                          out Closure result)
 {
+  diffuse = max(diffuse, vec4(0));
+  specular = max(specular, vec4(0));
+  roughness = saturate(roughness);
+  emissive = max(emissive, vec4(0));
   N = safe_normalize(N);
+  clearcoat = saturate(clearcoat);
+  clearcoat_roughness = saturate(clearcoat_roughness);
   CN = safe_normalize(CN);
+  occlusion = saturate(occlusion);
+
   vec3 V = coordinate_incoming(g_data.P);
 
   ClosureEmission emission_data;

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

@@ -4,6 +4,9 @@
 
 void node_emission(vec4 color, float strength, float weight, out Closure result)
 {
+  color = max(color, vec4(0));
+  strength = max(strength, 0);
+
   ClosureEmission emission_data;
   emission_data.weight = weight;
   emission_data.emission = color.rgb * strength;

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

@@ -10,7 +10,11 @@ void node_bsdf_glass(vec4 color,
                      const float do_multiscatter,
                      out Closure result)
 {
+  color = max(color, vec4(0));
+  roughness = saturate(roughness);
+  ior = max(ior, 1e-5);
   N = safe_normalize(N);
+
   vec3 V = coordinate_incoming(g_data.P);
   float NV = dot(N, V);
 

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

@@ -12,7 +12,10 @@ void node_bsdf_glossy(vec4 color,
                       const float do_multiscatter,
                       out Closure result)
 {
+  color = max(color, vec4(0));
+  roughness = saturate(roughness);
   N = safe_normalize(N);
+
   vec3 V = coordinate_incoming(g_data.P);
   float NV = dot(N, V);
 

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

@@ -10,6 +10,8 @@ void node_bsdf_hair(vec4 color,
                     float weight,
                     out Closure result)
 {
+  color = max(color, vec4(0));
+
 #if 0
   /* NOTE(fclem): This is the way it should be. But we don't have proper implementation of the hair
    * closure yet. For now fall back to a simpler diffuse surface so that we have at least a color

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

@@ -5,6 +5,9 @@
 void node_bsdf_refraction(
     vec4 color, float roughness, float ior, vec3 N, float weight, out Closure result)
 {
+  color = max(color, vec4(0));
+  roughness = saturate(roughness);
+  ior = max(ior, 1e-5);
   N = safe_normalize(N);
 
   ClosureRefraction refraction_data;

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

@@ -4,6 +4,8 @@
 
 void node_bsdf_sheen(vec4 color, float roughness, vec3 N, float weight, out Closure result)
 {
+  color = max(color, vec4(0));
+  roughness = saturate(roughness);
   N = safe_normalize(N);
 
   /* Fallback to diffuse. */

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

@@ -12,6 +12,10 @@ void node_subsurface_scattering(vec4 color,
                                 float do_sss,
                                 out Closure result)
 {
+  color = max(color, vec4(0));
+  scale = max(scale, 0);
+  radius = max(radius, vec3(0));
+  ior = max(ior, 1e-5);
   N = safe_normalize(N);
 
   ClosureDiffuse diffuse_data;

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

@@ -5,6 +5,7 @@
 void node_bsdf_toon(
     vec4 color, float size, float tsmooth, vec3 N, float weight, out Closure result)
 {
+  color = max(color, vec4(0));
   N = safe_normalize(N);
 
   /* Fallback to diffuse. */

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

@@ -4,6 +4,7 @@
 
 void node_bsdf_translucent(vec4 color, vec3 N, float weight, out Closure result)
 {
+  color = max(color, vec4(0));
   N = safe_normalize(N);
 
   ClosureTranslucent translucent_data;

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

@@ -4,6 +4,8 @@
 
 void node_bsdf_transparent(vec4 color, float weight, out Closure result)
 {
+  color = max(color, vec4(0));
+
   ClosureTransparency transparency_data;
   transparency_data.weight = weight;
   transparency_data.transmittance = color.rgb;

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

@@ -4,6 +4,9 @@
 
 void node_volume_absorption(vec4 color, float density, float weight, out Closure result)
 {
+  color = max(color, vec4(0));
+  density = max(density, 0);
+
   ClosureVolumeAbsorption volume_absorption_data;
   volume_absorption_data.weight = weight;
   volume_absorption_data.absorption = (1.0 - color.rgb) * density;

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

@@ -21,13 +21,20 @@ void node_volume_principled(vec4 color,
                             float layer,
                             out Closure result)
 {
+  color = max(color, vec4(0));
+  density = max(density, 0);
+  absorption_color = max(absorption_color, vec4(0));
+  emission_strength = max(emission_strength, 0);
+  emission_color = max(emission_color, vec4(0));
+  blackbody_intensity = max(blackbody_intensity, 0);
+  blackbody_tint = max(blackbody_tint, vec4(0));
+  temperature = max(temperature, 0);
+
   vec3 absorption_coeff = vec3(0.0);
   vec3 scatter_coeff = vec3(0.0);
   vec3 emission_coeff = vec3(0.0);
 
   /* Compute density. */
-  density = max(density, 0.0);
-
   if (density > 1e-5) {
     density = max(density * density_attribute.x, 0.0);
   }

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

@@ -5,6 +5,9 @@
 void node_volume_scatter(
     vec4 color, float density, float anisotropy, float weight, out Closure result)
 {
+  color = max(color, vec4(0));
+  density = max(density, 0);
+
   ClosureVolumeScatter volume_scatter_data;
   volume_scatter_data.weight = weight;
   volume_scatter_data.scattering = color.rgb * density;