Sculpt: Use new "offset brush" implementation for brush gravity

Part of #118145.

source/blender/editors/sculpt_paint/brushes/draw.cc

@@ -253,4 +253,14 @@ void do_nudge_brush(const Sculpt &sd, Object &object, Span<PBVHNode *> nodes)
   offset_positions(sd, object, offset * ss.cache->bstrength, nodes);
 }
 
+void do_gravity_brush(const Sculpt &sd, Object &object, Span<PBVHNode *> nodes)
+{
+  const SculptSession &ss = *object.sculpt;
+
+  const float3 offset = ss.cache->gravity_direction * -ss.cache->radius_squared * ss.cache->scale *
+                        sd.gravity_factor;
+
+  offset_positions(sd, object, offset, nodes);
+}
+
 }  // namespace blender::ed::sculpt_paint

source/blender/editors/sculpt_paint/brushes/types.hh

@@ -34,6 +34,7 @@ void do_elastic_deform_brush(const Sculpt &sd, Object &object, Span<PBVHNode *>
 void do_fill_brush(const Sculpt &sd, Object &object, Span<PBVHNode *> nodes);
 void do_flatten_brush(const Sculpt &sd, Object &ob, Span<PBVHNode *> nodes);
 void do_grab_brush(const Sculpt &sd, Object &ob, Span<PBVHNode *> nodes);
+void do_gravity_brush(const Sculpt &sd, Object &ob, Span<PBVHNode *> nodes);
 void do_inflate_brush(const Sculpt &sd, Object &ob, Span<PBVHNode *> nodes);
 /** A brush that modifies mask values instead of position. */
 void do_mask_brush(const Sculpt &sd, Object &object, Span<PBVHNode *> nodes);

source/blender/editors/sculpt_paint/sculpt.cc

@@ -3442,59 +3442,6 @@ float SCULPT_brush_plane_offset_get(const Sculpt &sd, const SculptSession &ss)
 
 /** \} */
 
-/* -------------------------------------------------------------------- */
-/** \name Sculpt Gravity Brush
- * \{ */
-
-static void do_gravity_task(SculptSession &ss,
-                            const Brush &brush,
-                            const float *offset,
-                            PBVHNode *node)
-{
-  PBVHVertexIter vd;
-  const MutableSpan<float3> proxy = BKE_pbvh_node_add_proxy(*ss.pbvh, *node).co;
-
-  SculptBrushTest test;
-  SculptBrushTestFn sculpt_brush_test_sq_fn = SCULPT_brush_test_init_with_falloff_shape(
-      ss, test, brush.falloff_shape);
-  const int thread_id = BLI_task_parallel_thread_id(nullptr);
-
-  BKE_pbvh_vertex_iter_begin (*ss.pbvh, node, vd, PBVH_ITER_UNIQUE) {
-    if (!sculpt_brush_test_sq_fn(test, vd.co)) {
-      continue;
-    }
-    const float fade = SCULPT_brush_strength_factor(
-        ss, brush, vd.co, sqrtf(test.dist), vd.no, vd.fno, vd.mask, vd.vertex, thread_id, nullptr);
-
-    mul_v3_v3fl(proxy[vd.i], offset, fade);
-  }
-  BKE_pbvh_vertex_iter_end;
-}
-
-static void do_gravity(const Sculpt &sd, Object &ob, Span<PBVHNode *> nodes, float bstrength)
-{
-  using namespace blender;
-  SculptSession &ss = *ob.sculpt;
-  const Brush &brush = *BKE_paint_brush_for_read(&sd.paint);
-
-  float offset[3];
-  float gravity_vector[3];
-
-  mul_v3_v3fl(gravity_vector, ss.cache->gravity_direction, -ss.cache->radius_squared);
-
-  /* Offset with as much as possible factored in already. */
-  mul_v3_v3v3(offset, gravity_vector, ss.cache->scale);
-  mul_v3_fl(offset, bstrength);
-
-  threading::parallel_for(nodes.index_range(), 1, [&](const IndexRange range) {
-    for (const int i : range) {
-      do_gravity_task(ss, brush, offset, nodes[i]);
-    }
-  });
-}
-
-/** \} */
-
 /* -------------------------------------------------------------------- */
 /** \name Sculpt Brush Utilities
  * \{ */
@@ -3946,7 +3893,7 @@ static void do_brush_action(const Scene &scene,
       !ELEM(
           brush.sculpt_tool, SCULPT_TOOL_CLOTH, SCULPT_TOOL_DRAW_FACE_SETS, SCULPT_TOOL_BOUNDARY))
   {
-    do_gravity(sd, ob, nodes, sd.gravity_factor);
+    do_gravity_brush(sd, ob, nodes);
   }
 
   if (brush.deform_target == BRUSH_DEFORM_TARGET_CLOTH_SIM) {