source/blender/gpu/intern/gpu_material.c

@@ -647,21 +647,6 @@ char *GPU_material_split_sub_function(GPUMaterial *material,
   SNPRINTF(func_link->name, "ntree_fn%d", material->generated_function_len++);
   BLI_addtail(&material->graph.material_functions, func_link);
 
-  /* Set value to break the link with the main graph. */
-  switch (return_type) {
-    case GPU_FLOAT:
-      GPU_link(material, "set_value_one", link);
-      break;
-    case GPU_VEC3:
-      GPU_link(material, "set_rgb_one", link);
-      break;
-    case GPU_VEC4:
-      GPU_link(material, "set_rgba_one", link);
-      break;
-    default:
-      BLI_assert(0);
-      break;
-  }
   return func_link->name;
 }
 

source/blender/gpu/shaders/gpu_shader_codegen_lib.glsl

@@ -263,9 +263,7 @@ vec3 dF_impl(vec3 v)
       g_derivative_flag = -1; \
       result.y = (fn); \
       g_derivative_flag = 0; \
-      result -= vec2((fn)); \
     }
-
 #endif
 
 /* TODO(fclem): Remove. */

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

@@ -12,8 +12,13 @@ void differentiate_texco(vec4 v, out vec3 df)
   df = v.xyz + dF_impl(v.xyz);
 }
 
-void node_bump(
-    float strength, float dist, float height, vec3 N, vec2 dHd, float invert, out vec3 result)
+void node_bump(float strength,
+               float dist,
+               float height,
+               vec3 N,
+               vec2 height_xy,
+               float invert,
+               out vec3 result)
 {
   N = normalize(N);
   dist *= FrontFacing ? invert : -invert;
@@ -29,6 +34,7 @@ void node_bump(
   /* Compute surface gradient and determinant. */
   float det = dot(dPdx, Rx);
 
+  vec2 dHd = height_xy - vec2(height);
   vec3 surfgrad = dHd.x * Rx + dHd.y * Ry;
 
   strength = max(strength, 0.0);

source/blender/nodes/shader/nodes/node_shader_bump.cc

@@ -59,6 +59,14 @@ static int gpu_shader_bump(GPUMaterial *mat,
 
   const char *height_function = GPU_material_split_sub_function(mat, GPU_FLOAT, &in[2].link);
 
+  /* TODO (Miguel Pozo):
+   * Currently, this doesn't compute the actual differentials, just the height at dX and dY
+   * offsets. The actual differentials are computed inside the GLSL node_bump function by
+   * substracting the height input. This avoids redundant computations when the height input is
+   * also needed by regular nodes as part in the main function (See #103903 for context).
+   * A better option would be to add a "value" input socket (in this case the height) to the
+   * differentiate node, but currently this kind of intermediate nodes are pruned in the codegen
+   * process (see #104265), so we need to fix that first. */
   GPUNodeLink *dheight = GPU_differentiate_float_function(height_function);
 
   float invert = (node->custom1) ? -1.0 : 1.0;