Curves: support sculpting on deformed curves

Previously, curves sculpt tools only worked on original data. This was
very limiting, because one could effectively only sculpt the curves when
all procedural effects were turned off. This patch adds support for curves
sculpting while looking the result of procedural effects (like deformation
based on the surface mesh). This functionality is also known as "crazy space"
support in Blender.

For more details see D15407.

Differential Revision: https://developer.blender.org/D15407

1 files changed, 36 insertions, 8 deletions

diff --git a/source/blender/editors/sculpt_paint/curves_sculpt_brush.cc b/source/blender/editors/sculpt_paint/curves_sculpt_brush.cc
index ff27c16dc36..9803c6fdcc6 100644
--- a/source/blender/editors/sculpt_paint/curves_sculpt_brush.cc
+++ b/source/blender/editors/sculpt_paint/curves_sculpt_brush.cc
@@ -8,6 +8,9 @@
 #include "BKE_bvhutils.h"
 #include "BKE_context.h"
 #include "BKE_curves.hh"
+#include "BKE_modifier.h"
+#include "BKE_object.h"
+#include "BKE_report.h"
 
 #include "ED_view3d.h"
 
@@ -20,6 +23,10 @@
 #include "BLI_length_parameterize.hh"
 #include "BLI_task.hh"
 
+#include "DEG_depsgraph_query.h"
+
+#include "BLT_translation.h"
+
 /**
  * The code below uses a prefix naming convention to indicate the coordinate space:
  * cu: Local space of the curves object that is being edited.
@@ -48,7 +55,8 @@ static std::optional<float3> find_curves_brush_position(const CurvesGeometry &cu
                                                         const float brush_radius_re,
                                                         const ARegion &region,
                                                         const RegionView3D &rv3d,
-                                                        const Object &object)
+                                                        const Object &object,
+                                                        const Span<float3> positions)
 {
   /* This value might have to be adjusted based on user feedback. */
   const float brush_inner_radius_re = std::min<float>(brush_radius_re, (float)UI_UNIT_X / 3.0f);
@@ -88,8 +96,6 @@ static std::optional<float3> find_curves_brush_position(const CurvesGeometry &cu
     }
   };
 
-  const Span<float3> positions = curves.positions();
-
   BrushPositionCandidate best_candidate = threading::parallel_reduce(
       curves.curves_range(),
       128,
@@ -175,20 +181,21 @@ std::optional<CurvesBrush3D> sample_curves_3d_brush(const Depsgraph &depsgraph,
 {
   const Curves &curves_id = *static_cast<Curves *>(curves_object.data);
   const CurvesGeometry &curves = CurvesGeometry::wrap(curves_id.geometry);
-  const Object *surface_object = curves_id.surface;
+  Object *surface_object = curves_id.surface;
+  Object *surface_object_eval = DEG_get_evaluated_object(&depsgraph, surface_object);
 
   float3 center_ray_start_wo, center_ray_end_wo;
   ED_view3d_win_to_segment_clipped(
       &depsgraph, &region, &v3d, brush_pos_re, center_ray_start_wo, center_ray_end_wo, true);
 
   /* Shorten ray when the surface object is hit. */
-  if (surface_object != nullptr) {
+  if (surface_object_eval != nullptr) {
     const float4x4 surface_to_world_mat = surface_object->obmat;
     const float4x4 world_to_surface_mat = surface_to_world_mat.inverted();
 
-    Mesh &surface = *static_cast<Mesh *>(surface_object->data);
+    Mesh *surface_eval = BKE_object_get_evaluated_mesh(surface_object_eval);
     BVHTreeFromMesh surface_bvh;
-    BKE_bvhtree_from_mesh_get(&surface_bvh, &surface, BVHTREE_FROM_LOOPTRI, 2);
+    BKE_bvhtree_from_mesh_get(&surface_bvh, surface_eval, BVHTREE_FROM_LOOPTRI, 2);
     BLI_SCOPED_DEFER([&]() { free_bvhtree_from_mesh(&surface_bvh); });
 
     const float3 center_ray_start_su = world_to_surface_mat * center_ray_start_wo;
@@ -222,6 +229,9 @@ std::optional<CurvesBrush3D> sample_curves_3d_brush(const Depsgraph &depsgraph,
   const float3 center_ray_start_cu = world_to_curves_mat * center_ray_start_wo;
   const float3 center_ray_end_cu = world_to_curves_mat * center_ray_end_wo;
 
+  const bke::crazyspace::GeometryDeformation deformation =
+      bke::crazyspace::get_evaluated_curves_deformation(depsgraph, curves_object);
+
   const std::optional<float3> brush_position_optional_cu = find_curves_brush_position(
       curves,
       center_ray_start_cu,
@@ -229,7 +239,8 @@ std::optional<CurvesBrush3D> sample_curves_3d_brush(const Depsgraph &depsgraph,
       brush_radius_re,
       region,
       rv3d,
-      curves_object);
+      curves_object,
+      deformation.positions);
   if (!brush_position_optional_cu.has_value()) {
     /* Nothing found. */
     return std::nullopt;
@@ -380,4 +391,21 @@ CurvesSculptCommonContext::CurvesSculptCommonContext(const bContext &C)
   this->rv3d = CTX_wm_region_view3d(&C);
 }
 
+void report_missing_surface(ReportList *reports)
+{
+  BKE_report(reports, RPT_WARNING, TIP_("Missing surface mesh"));
+}
+
+void report_missing_uv_map_on_original_surface(ReportList *reports)
+{
+  BKE_report(
+      reports, RPT_WARNING, TIP_("Missing UV map for attaching curves on original surface"));
+}
+
+void report_missing_uv_map_on_evaluated_surface(ReportList *reports)
+{
+  BKE_report(
+      reports, RPT_WARNING, TIP_("Missing UV map for attaching curves on evaluated surface"));
+}
+
 }  // namespace blender::ed::sculpt_paint