intern/cycles/kernel/osl/shaders/node_normal_map.osl

@@ -33,11 +33,16 @@ shader node_normal_map(float Strength = 1.0,
     if (getattribute(attr_name, tangent) && getattribute(attr_sign_name, tangent_sign) &&
         (!is_smooth || getattribute("geom:normal_map_normal", ninterp)))
     {
-      // apply normal map
+      /* apply normal map */
       vector B = tangent_sign * cross(ninterp, tangent);
+
+      /* apply strength */
+      mcolor[0] *= Strength;
+      mcolor[1] *= Strength;
+
       Normal = normalize(mcolor[0] * tangent + mcolor[1] * B + mcolor[2] * ninterp);
 
-      // transform to world space
+      /* transform to world space */
       Normal = normalize(transform("object", "world", Normal));
     }
     else {
@@ -70,6 +75,6 @@ shader node_normal_map(float Strength = 1.0,
     Normal = -Normal;
   }
 
-  if (Strength != 1.0)
+  if (Strength != 1.0 && space != "tangent")
     Normal = normalize(N + (Normal - N) * max(Strength, 0.0));
 }

intern/cycles/kernel/svm/tex_coord.h

@@ -276,7 +276,7 @@ ccl_device_noinline void svm_node_normal_map(KernelGlobals kg,
 
   bool is_backfacing = (sd->flag & SD_BACKFACING) != 0;
   float3 N;
-
+  float strength = stack_load_float(stack, strength_offset);
   if (space == NODE_NORMAL_MAP_TANGENT) {
     /* tangent space */
     if (sd->object == OBJECT_NONE || (sd->type & PRIMITIVE_TRIANGLE) == 0) {
@@ -313,6 +313,9 @@ ccl_device_noinline void svm_node_normal_map(KernelGlobals kg,
 
       object_inverse_normal_transform(kg, sd, &normal);
     }
+    /* Apply strength in the tangent case. */
+    color.x *= strength;
+    color.y *= strength;
 
     /* apply normal map */
     float3 B = sign * cross(normal, tangent);
@@ -335,6 +338,11 @@ ccl_device_noinline void svm_node_normal_map(KernelGlobals kg,
       object_normal_transform(kg, sd, &N);
     else
       N = safe_normalize(N);
+    /* Apply strength in all but tangent space. */
+    if (strength != 1.0f) {
+      strength = max(strength, 0.0f);
+      N = safe_normalize(sd->N + (N - sd->N) * strength);
+    }
   }
 
   /* invert normal for backfacing polygons */
@@ -342,13 +350,6 @@ ccl_device_noinline void svm_node_normal_map(KernelGlobals kg,
     N = -N;
   }
 
-  float strength = stack_load_float(stack, strength_offset);
-
-  if (strength != 1.0f) {
-    strength = max(strength, 0.0f);
-    N = safe_normalize(sd->N + (N - sd->N) * strength);
-  }
-
   if (is_zero(N)) {
     N = sd->N;
   }

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

@@ -1,6 +1,6 @@
 
 #ifdef OBINFO_LIB
-void node_normal_map(vec4 tangent, vec3 texnormal, out vec3 outnormal)
+void node_normal_map(vec4 tangent, float strength, vec3 texnormal, out vec3 outnormal)
 {
   if (all(equal(tangent, vec4(0.0, 0.0, 0.0, 1.0)))) {
     outnormal = g_data.Ni;
@@ -9,6 +9,9 @@ void node_normal_map(vec4 tangent, vec3 texnormal, out vec3 outnormal)
   tangent *= (FrontFacing ? 1.0 : -1.0);
   vec3 B = tangent.w * cross(g_data.Ni, tangent.xyz) * sign(ObjectInfo.w);
 
+  /* Apply strength here instead of in node_normal_map_mix for tangent space. */
+  texnormal.xy *= strength;
+
   outnormal = texnormal.x * tangent.xyz + texnormal.y * B + texnormal.z * g_data.Ni;
   outnormal = normalize(outnormal);
 }
@@ -26,5 +29,5 @@ void color_to_blender_normal_new_shading(vec3 color, out vec3 normal)
 
 void node_normal_map_mix(float strength, vec3 newnormal, out vec3 outnormal)
 {
-  outnormal = normalize(mix(g_data.N, newnormal, max(strength, 0.0)));
+  outnormal = normalize(mix(g_data.N, newnormal, max(0.0, strength)));
 }

source/blender/nodes/shader/nodes/node_shader_normal_map.cc

@@ -94,12 +94,15 @@ static int gpu_shader_normal_map(GPUMaterial *mat,
   switch (nm->space) {
     case SHD_SPACE_TANGENT:
       GPU_material_flag_set(mat, GPU_MATFLAG_OBJECT_INFO);
+      /* We return directly from the node_normal_map as strength
+       * has already been applied for the tangent case */
       GPU_link(mat,
                "node_normal_map",
                GPU_attribute(mat, CD_TANGENT, nm->uv_map),
+               strength,
                newnormal,
-               &newnormal);
-      break;
+               &out[0].link);
+      return true;
     case SHD_SPACE_OBJECT:
     case SHD_SPACE_BLENDER_OBJECT:
       GPU_link(mat, "normal_transform_object_to_world", newnormal, &newnormal);
@@ -110,6 +113,7 @@ static int gpu_shader_normal_map(GPUMaterial *mat,
       break;
   }
 
+  /* Final step - mix and apply strength for all other than tangent space. */
   GPU_link(mat, "node_normal_map_mix", strength, newnormal, &out[0].link);
 
   return true;