Half-lambert factor in Shader Info node

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

@@ -404,7 +404,8 @@ void calc_shader_info(vec3 position,
                       out vec4 half_light,
                       out float shadows,
                       out float self_shadows,
-                      out vec4 ambient)
+                      out vec4 ambient,
+                      out float half_lambert)
 {
   calc_shader_info(position,
                    normal,
@@ -413,7 +414,8 @@ void calc_shader_info(vec3 position,
                    half_light,
                    shadows,
                    self_shadows,
-                   ambient);
+                   ambient,
+                   half_lambert);
 }
 
 /* Use custom (Per-Node) light groups */
@@ -424,7 +426,8 @@ void calc_shader_info(vec3 position,
                       out vec4 half_light,
                       out float shadows,
                       out float self_shadows,
-                      out vec4 ambient)
+                      out vec4 ambient,
+                      out float half_lambert)
 {
   ClosureEvalCommon cl_common = closure_Common_eval_init(CLOSURE_INPUT_COMMON_DEFAULT);
   cl_common.P = position;
@@ -436,6 +439,7 @@ void calc_shader_info(vec3 position,
   float self_shadow_accum = 0.0;
   float light_accum = 0.0;
   half_light = vec4(0.0);
+  half_lambert = 0.0;
 
   for (int i = 0; i < laNumLight && i < MAX_LIGHT; i++) {
     ClosureLightData light = closure_light_eval_init(cl_common, i);
@@ -459,6 +463,8 @@ void calc_shader_info(vec3 position,
 
     float radiance = light_diffuse(light.data, n_n, cl_common.V, light.L);
     half_light += vec4(light.data.l_color * light.data.l_diff * radiance, 0.0);
+    vec3 L = (ld.l_type == SUN) ? -ld.l_forward : (light.L.xyz / light.L.w);
+    half_lambert += 0.5 * dot(L, n_n) + 0.5;
   }
 
   shadows = (1.0 - (shadow_accum / max(light_accum, 1.0)));

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

@@ -48,8 +48,8 @@ Closure nodetree_exec();
 vec4 closure_to_rgba(Closure cl);
 
 /* Goo-engine node internals */
-void calc_shader_info(vec3 position, vec3 normal, ivec4 light_groups, ivec4 light_group_shadows, out vec4 half_light, out float shadows, out float self_shadows, out vec4 ambient);
-void calc_shader_info(vec3 position, vec3 normal, out vec4 half_light, out float shadows, out float self_shadows, out vec4 ambient);
+void calc_shader_info(vec3 position, vec3 normal, ivec4 light_groups, ivec4 light_group_shadows, out vec4 half_light, out float shadows, out float self_shadows, out vec4 ambient, out float half_lambert);
+void calc_shader_info(vec3 position, vec3 normal, out vec4 half_light, out float shadows, out float self_shadows, out vec4 ambient, out float half_lambert);
 void screenspace_info(vec3 viewPos, out vec4 scene_col, out float scene_depth);
 void screenspace_curvature(float iiterations, float sample_scale, float clamp_dist, vec3 scale, out float scene_curvature, out float scene_rim);
 

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

@@ -1,14 +1,14 @@
 
 void node_shader_info(vec3 position, vec3 normal,
-out vec4 half_light, out float shadows, out float self_shadows, out vec4 ambient)
+out vec4 half_light, out float shadows, out float self_shadows, out vec4 ambient, out float half_lambert)
 {
     // Implicitly included by eevee shader linking.
-    calc_shader_info(position, normal, half_light, shadows, self_shadows, ambient);
+    calc_shader_info(position, normal, half_light, shadows, self_shadows, ambient, half_lambert);
 }
 
 void node_shader_info_light_groups(vec3 position, vec3 normal, vec4 light_groups, vec4 light_group_shadows,
-out vec4 half_light, out float shadows, out float self_shadows, out vec4 ambient)
+out vec4 half_light, out float shadows, out float self_shadows, out vec4 ambient, out float half_lambert)
 {
     // Implicitly included by eevee shader linking.
-    calc_shader_info(position, normal, floatBitsToInt(light_groups), floatBitsToInt(light_group_shadows), half_light, shadows, self_shadows, ambient);
+    calc_shader_info(position, normal, floatBitsToInt(light_groups), floatBitsToInt(light_group_shadows), half_light, shadows, self_shadows, ambient, half_lambert);
 }

source/blender/nodes/shader/nodes/node_shader_shader_info.cc

@@ -16,6 +16,7 @@ static void node_declare(NodeDeclarationBuilder &b)
  b.add_output<decl::Float>(N_("Cast Shadows"));
  b.add_output<decl::Float>(N_("Self Shadows"));
  b.add_output<decl::Color>(N_("Ambient Lighting"));
+ b.add_output<decl::Float>(N_("Half-lambert factor"));
 }
 
 static void node_shader_init_shader_info(bNodeTree* /*ntree*/, bNode *node)