Array Brush: Add template code and support geometry modifications

source/blender/blenkernel/BKE_paint.h

@@ -524,6 +524,10 @@ typedef struct SculptSession {
   bool show_mask;
   bool show_face_sets;
 
+  /* Setting this to true allows a PBVH rebuild when evaluating the object even if the stroke or
+  * filter caches are active. */
+  bool needs_pbvh_rebuild;
+
   /* Painting on deformed mesh */
   bool deform_modifiers_active; /* Object is deformed with some modifiers. */
   float (*orig_cos)[3];         /* Coords of un-deformed mesh. */

source/blender/blenkernel/intern/brush.c

@@ -2001,6 +2001,7 @@ void BKE_brush_sculpt_reset(Brush *br)
     case SCULPT_TOOL_DRAW_FACE_SETS:
     case SCULPT_TOOL_DISPLACEMENT_ERASER:
     case SCULPT_TOOL_DISPLACEMENT_SMEAR:
+    case SCULPT_TOOL_ARRAY:
       br->add_col[0] = 0.75f;
       br->add_col[1] = 0.75f;
       br->add_col[2] = 0.75f;

source/blender/blenkernel/intern/paint.c

@@ -1763,8 +1763,8 @@ void BKE_sculpt_update_object_before_eval(Object *ob)
   /* Update before mesh evaluation in the dependency graph. */
   SculptSession *ss = ob->sculpt;
 
-  if (ss && ss->building_vp_handle == false) {
-    if (!ss->cache && !ss->filter_cache && !ss->expand_cache) {
+  if (ss && (ss->building_vp_handle == false || ss->needs_pbvh_rebuild)) {
+    if (ss->needs_pbvh_rebuild || (!ss->cache && !ss->filter_cache && !ss->expand_cache)) {
       /* We free pbvh on changes, except in the middle of drawing a stroke
        * since it can't deal with changing PVBH node organization, we hope
        * topology does not change in the meantime .. weak. */

source/blender/editors/sculpt_paint/CMakeLists.txt

@@ -56,6 +56,7 @@ set(SRC
   paint_vertex_weight_ops.c
   paint_vertex_weight_utils.c
   sculpt.c
+  sculpt_array.c
   sculpt_automasking.c
   sculpt_boundary.c
   sculpt_cloth.c

source/blender/editors/sculpt_paint/sculpt.c

@@ -2513,6 +2513,9 @@ static float brush_strength(const Sculpt *sd,
     case SCULPT_TOOL_GRAB:
       return root_alpha * feather;
 
+    case SCULPT_TOOL_ARRAY:
+      return root_alpha * feather;
+
     case SCULPT_TOOL_ROTATE:
       return alpha * pressure * feather;
 
@@ -6941,6 +6944,9 @@ static void do_brush_action(Sculpt *sd, Object *ob, Brush *brush, UnifiedPaintSe
     case SCULPT_TOOL_SYMMETRIZE:
       SCULPT_do_symmetrize_brush(sd, ob, nodes, totnode);
       break;
+    case SCULPT_TOOL_ARRAY:
+      SCULPT_do_array_brush(sd, ob, nodes, totnode);
+      break;
   }
 
   if (!ELEM(brush->sculpt_tool, SCULPT_TOOL_SMOOTH, SCULPT_TOOL_MASK) &&
@@ -7541,6 +7547,8 @@ static const char *sculpt_tool_name(Sculpt *sd)
       return "Symmetrize Brush";
     case SCULPT_TOOL_TWIST:
       return "Clay Strips Brush";
+    case SCULPT_TOOL_ARRAY:
+      return "Array Brush";
   }
 
   return "Sculpting";
@@ -7824,6 +7832,7 @@ static bool sculpt_needs_delta_from_anchored_origin(Brush *brush)
            SCULPT_TOOL_GRAB,
            SCULPT_TOOL_POSE,
            SCULPT_TOOL_BOUNDARY,
+           SCULPT_TOOL_ARRAY,
            SCULPT_TOOL_THUMB,
            SCULPT_TOOL_ELASTIC_DEFORM)) {
     return true;
@@ -7876,6 +7885,7 @@ static void sculpt_update_brush_delta(UnifiedPaintSettings *ups, Object *ob, Bru
             SCULPT_TOOL_SNAKE_HOOK,
             SCULPT_TOOL_POSE,
             SCULPT_TOOL_BOUNDARY,
+            SCULPT_TOOL_ARRAY,
             SCULPT_TOOL_THUMB) &&
       !sculpt_brush_use_topology_rake(ss, brush)) {
     return;
@@ -8797,6 +8807,11 @@ static bool sculpt_stroke_test_start(bContext *C, struct wmOperator *op, const f
     sculpt_update_cache_invariants(C, sd, ss, op, mouse);
 
     SCULPT_undo_push_begin(ob, sculpt_tool_name(sd));
+    
+    Brush *brush = BKE_paint_brush(&sd->paint);
+    if (brush->sculpt_tool == SCULPT_TOOL_ARRAY) {
+      SCULPT_undo_push_node(ob, NULL, SCULPT_UNDO_GEOMETRY);
+    }
 
     return true;
   }
@@ -8839,6 +8854,19 @@ static void sculpt_stroke_update_step(bContext *C,
   }
 
   do_symmetrical_brush_actions(sd, ob, do_brush_action, ups);
+
+   if (ss->needs_pbvh_rebuild) {
+    /* The mesh was modified, rebuild the PBVH. */
+    SCULPT_pbvh_clear(ob);
+    Depsgraph *depsgraph = CTX_data_ensure_evaluated_depsgraph(C);
+    BKE_sculpt_update_object_for_edit(depsgraph, ob, true, false, false);
+
+    if (brush->sculpt_tool == SCULPT_TOOL_ARRAY) {
+      SCULPT_tag_update_overlays(C);
+    }
+    ss->needs_pbvh_rebuild = false;
+  }
+
   sculpt_combine_proxies(sd, ob);
 
   if (brush->sculpt_tool == SCULPT_TOOL_FAIRING) {
@@ -8939,6 +8967,10 @@ static void sculpt_stroke_done(const bContext *C, struct PaintStroke *UNUSED(str
   SCULPT_cache_free(ss->cache);
   ss->cache = NULL;
 
+  if (brush->sculpt_tool == SCULPT_TOOL_ARRAY) {
+    SCULPT_undo_push_node(ob, NULL, SCULPT_UNDO_GEOMETRY);
+  }
+  
   SCULPT_undo_push_end();
 
   if (brush->sculpt_tool == SCULPT_TOOL_MASK) {

source/blender/editors/sculpt_paint/sculpt_intern.h

@@ -535,6 +535,9 @@ void SCULPT_boundary_edges_preview_draw(const uint gpuattr,
                                         const float outline_alpha);
 void SCULPT_boundary_pivot_line_preview_draw(const uint gpuattr, struct SculptSession *ss);
 
+/* Array Brush. */
+void SCULPT_do_array_brush(Sculpt *sd, Object *ob, PBVHNode **nodes, int totnode);
+
 /* Multi-plane Scrape Brush. */
 void SCULPT_do_multiplane_scrape_brush(Sculpt *sd, Object *ob, PBVHNode **nodes, int totnode);
 void SCULPT_multiplane_scrape_preview_draw(const uint gpuattr,

source/blender/makesdna/DNA_brush_enums.h

@@ -478,6 +478,7 @@ typedef enum eBrushSculptTool {
   SCULPT_TOOL_SCENE_PROJECT = 34,
   SCULPT_TOOL_SYMMETRIZE = 35,
   SCULPT_TOOL_TWIST = 36,
+  SCULPT_TOOL_ARRAY = 37,
 } eBrushSculptTool;
 
 /* Brush.uv_sculpt_tool */

source/blender/makesrna/intern/rna_brush.c

@@ -142,6 +142,7 @@ const EnumPropertyItem rna_enum_brush_sculpt_tool_items[] = {
     {SCULPT_TOOL_SCENE_PROJECT, "SCENE_PROJECT", ICON_BRUSH_MASK, "Scene Project", ""},
     {SCULPT_TOOL_DRAW_FACE_SETS, "DRAW_FACE_SETS", ICON_BRUSH_MASK, "Draw Face Sets", ""},
     {SCULPT_TOOL_SYMMETRIZE, "SYMMETRIZE", ICON_BRUSH_SCULPT_DRAW, "Symmetrize", ""},
+    {SCULPT_TOOL_ARRAY, "ARRAY", ICON_BRUSH_SCULPT_DRAW, "Array", ""},
     {0, NULL, 0, NULL, NULL},
 };
 /* clang-format on */