Sculpt: add option to fade face sets with a

Moire pattern instead of transparently.

source/blender/blenloader/intern/versioning_300.c

@@ -2240,6 +2240,22 @@ void blo_do_versions_300(FileData *fd, Library *UNUSED(lib), Main *bmain)
         BKE_brush_mapping_inherit_all(ch);
       }
     }
+
+    if (!MAIN_VERSION_ATLEAST(bmain, 300, 39)) {
+      if (!DNA_struct_elem_find(
+              fd->filesdna, "View3DOverlay", "float", "sculpt_mode_face_sets_moire_scale")) {
+        for (bScreen *screen = bmain->screens.first; screen; screen = screen->id.next) {
+          LISTBASE_FOREACH (ScrArea *, area, &screen->areabase) {
+            LISTBASE_FOREACH (SpaceLink *, sl, &area->spacedata) {
+              if (sl->spacetype == SPACE_VIEW3D) {
+                View3D *v3d = (View3D *)sl;
+                v3d->overlay.sculpt_mode_face_sets_moire_scale = 0.45f;
+              }
+            }
+          }
+        }
+      }
+    }
   }
 
   /**

source/blender/draw/engines/overlay/overlay_sculpt.c

@@ -40,9 +40,18 @@ void OVERLAY_sculpt_cache_init(OVERLAY_Data *vedata)
 
   GPUShader *sh = OVERLAY_shader_sculpt_mask();
   pd->sculpt_mask_grp = grp = DRW_shgroup_create(sh, psl->sculpt_mask_ps);
+
   DRW_shgroup_uniform_float_copy(grp, "maskOpacity", pd->overlay.sculpt_mode_mask_opacity);
+
   DRW_shgroup_uniform_float_copy(
       grp, "faceSetsOpacity", pd->overlay.sculpt_mode_face_sets_opacity);
+  DRW_shgroup_uniform_float_copy(
+      grp, "faceSetsPatSeed", pd->overlay.sculpt_mode_face_sets_moire_seed);
+  DRW_shgroup_uniform_bool_copy(
+      grp, "useMoire", pd->overlay.sculpt_flag & V3D_OVERLAY_SCULPT_FSET_MOIRE);
+
+  DRW_shgroup_uniform_float_copy(
+      grp, "faceSetsPatScale", 0.5f * (1.1f - pd->overlay.sculpt_mode_face_sets_moire_scale));
 }
 
 void OVERLAY_sculpt_cache_populate(OVERLAY_Data *vedata, Object *ob)

source/blender/draw/engines/overlay/shaders/sculpt_mask_frag.glsl

@@ -1,10 +1,43 @@
+uniform float faceSetsOpacity;
+uniform float faceSetsPatSeed;
+uniform float faceSetsPatScale;
+uniform bool useMoire;
 
 flat in vec3 faceset_color;
 in float mask_color;
 
 out vec4 fragColor;
 
+float tent(float f)
+{
+  return 1.0 - abs(fract(f) - 0.5) * 2.0;
+}
+
 void main()
 {
-  fragColor = vec4(faceset_color * vec3(mask_color), 1.0);
+  vec3 final_color = faceset_color;
+  vec3 white = vec3(1.0, 1.0, 1.0);
+
+  if (!useMoire) {
+    fragColor = vec4(final_color * vec3(mask_color), 1.0);
+    return;
+  }
+
+  vec2 xy = gl_FragCoord.xy * faceSetsPatScale;
+
+  /* Basic moire pattern */
+
+  float seed = 1.0 / 3.0 + faceSetsPatSeed;
+
+  float dx1 = tent(xy.x);
+  float dy1 = tent(xy.y);
+  float dx2 = tent(tent(seed) * xy.x + tent(seed * seed + 0.5) * xy.y);
+  float dy2 = tent(tent(seed) * xy.y - tent(seed * seed + 0.5) * xy.x);
+
+  float fac = (dx1 + dy1 + dx2 + dy2) / 4.0;
+  fac = step(fac, 1.0 - faceSetsOpacity);
+
+  final_color += (white - final_color) * fac;
+
+  fragColor = vec4(final_color * vec3(mask_color), 1.0);
 }

source/blender/draw/engines/overlay/shaders/sculpt_mask_vert.glsl

@@ -1,3 +1,4 @@
+uniform bool useMoire;
 
 uniform float maskOpacity;
 uniform float faceSetsOpacity;
@@ -16,7 +17,7 @@ void main()
   vec3 world_pos = point_object_to_world(pos);
   gl_Position = point_world_to_ndc(world_pos);
 
-  faceset_color = mix(vec3(1.0), fset, faceSetsOpacity);
+  faceset_color = !useMoire ? mix(vec3(1.0), fset, sqrt(faceSetsOpacity)) : fset;
   mask_color = 1.0 - (msk * maskOpacity);
 
 #ifdef USE_WORLD_CLIP_PLANES

source/blender/makesdna/DNA_view3d_defaults.h

@@ -61,6 +61,7 @@
      * we typically want to see shading too. */ \
     .sculpt_mode_mask_opacity = 0.75f, \
     .sculpt_mode_face_sets_opacity = 1.0f, \
+    .sculpt_mode_face_sets_moire_scale = 0.45f,\
  \
     .edit_flag = V3D_OVERLAY_EDIT_FACES | V3D_OVERLAY_EDIT_SEAMS | \
                              V3D_OVERLAY_EDIT_SHARP | V3D_OVERLAY_EDIT_FREESTYLE_EDGE | \

source/blender/makesdna/DNA_view3d_types.h

@@ -219,6 +219,11 @@ typedef struct View3DOverlay {
   float weight_paint_mode_opacity;
   float sculpt_mode_mask_opacity;
   float sculpt_mode_face_sets_opacity;
+  float sculpt_mode_face_sets_moire_seed;
+  float sculpt_mode_face_sets_moire_scale;
+
+  /** Sculpt mode settings*/
+  int sculpt_flag;
 
   /** Armature edit/pose mode settings. */
   float xray_alpha_bone;
@@ -239,8 +244,6 @@ typedef struct View3DOverlay {
   float gpencil_vertex_paint_opacity;
   /** Handles display type for curves. */
   int handle_display;
-
-  char _pad[4];
 } View3DOverlay;
 
 /* View3DOverlay->handle_display */
@@ -580,6 +583,11 @@ enum {
   V3D_OVERLAY_WPAINT_CONTOURS = (1 << 0),
 };
 
+/** #View3DOverlay.sculpt_flag */
+enum {
+  V3D_OVERLAY_SCULPT_FSET_MOIRE = (1 << 0),
+};
+
 /** #View3D.around */
 enum {
   /* center of the bounding box */

source/blender/makesrna/intern/rna_space.c

@@ -4496,6 +4496,23 @@ static void rna_def_space_view3d_overlay(BlenderRNA *brna)
   RNA_def_property_range(prop, 0.0f, 1.0f);
   RNA_def_property_update(prop, NC_SPACE | ND_SPACE_VIEW3D, NULL);
 
+  prop = RNA_def_property(srna, "sculpt_mode_face_sets_moire_seed", PROP_FLOAT, PROP_FACTOR);
+  RNA_def_property_float_sdna(prop, NULL, "overlay.sculpt_mode_face_sets_moire_seed");
+  RNA_def_property_ui_text(prop, "Pattern Seed", "Sculpt Face Sets Pattern Seed");
+  RNA_def_property_range(prop, 0.0f, 1.0f);
+  RNA_def_property_update(prop, NC_SPACE | ND_SPACE_VIEW3D, NULL);
+
+  prop = RNA_def_property(srna, "sculpt_mode_use_face_set_moire", PROP_BOOLEAN, PROP_NONE);
+  RNA_def_property_boolean_sdna(prop, NULL, "overlay.sculpt_flag", V3D_OVERLAY_SCULPT_FSET_MOIRE);
+  RNA_def_property_ui_text(prop, "Moire", "Draw face sets with moire pattern");
+  RNA_def_property_update(prop, NC_SPACE | ND_SPACE_VIEW3D, NULL);
+
+  prop = RNA_def_property(srna, "sculpt_mode_face_sets_moire_scale", PROP_FLOAT, PROP_FACTOR);
+  RNA_def_property_float_sdna(prop, NULL, "overlay.sculpt_mode_face_sets_moire_scale");
+  RNA_def_property_ui_text(prop, "Pattern Scale", "Sculpt Face Sets Pattern Scale");
+  RNA_def_property_range(prop, 0.0f, 1.0f);
+  RNA_def_property_update(prop, NC_SPACE | ND_SPACE_VIEW3D, NULL);
+
   /* grease pencil paper settings */
   prop = RNA_def_property(srna, "show_annotation", PROP_BOOLEAN, PROP_NONE);
   RNA_def_property_boolean_sdna(prop, NULL, "flag2", V3D_SHOW_ANNOTATION);