curves_sculpt_add.cc

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/* SPDX-FileCopyrightText: 2023 Blender Authors
 *
 * SPDX-License-Identifier: GPL-2.0-or-later */
 
#include <algorithm>
 
#include "curves_sculpt_intern.hh"
 
#include "BLI_bounds.hh"
#include "BLI_kdtree.h"
#include "BLI_math_geom.h"
#include "BLI_math_matrix.hh"
#include "BLI_rand.hh"
#include "BLI_vector.hh"
 
#include "DEG_depsgraph.hh"
 
#include "BKE_brush.hh"
#include "BKE_bvhutils.hh"
#include "BKE_context.hh"
#include "BKE_curves.hh"
#include "BKE_geometry_set.hh"
#include "BKE_mesh.hh"
#include "BKE_mesh_runtime.hh"
#include "BKE_mesh_sample.hh"
#include "BKE_modifier.hh"
#include "BKE_object.hh"
#include "BKE_paint.hh"
 
#include "DNA_brush_enums.h"
#include "DNA_brush_types.h"
#include "DNA_curves_types.h"
#include "DNA_object_types.h"
#include "DNA_screen_types.h"
 
#include "ED_screen.hh"
#include "ED_view3d.hh"
 
#include "GEO_add_curves_on_mesh.hh"
 
#include "WM_api.hh"
 
#include "DEG_depsgraph_query.hh"

 
namespace blender::ed::sculpt_paint {
 
using bke::CurvesGeometry;
 
class AddOperation : public CurvesSculptStrokeOperation {
 private:
  KDTree_3d *curve_roots_kdtree_ = nullptr;
 
  friend struct AddOperationExecutor;
 
 public:
  ~AddOperation() override
  {
    if (curve_roots_kdtree_ != nullptr) {
      BLI_kdtree_3d_free(curve_roots_kdtree_);
    }
  }
 
  void on_stroke_extended(const bContext &C, const StrokeExtension &stroke_extension) override;
};

struct AddOperationExecutor {
  AddOperation *self_ = nullptr;
  CurvesSculptCommonContext ctx_;
 
  Object *curves_ob_orig_ = nullptr;
  Curves *curves_id_orig_ = nullptr;
  CurvesGeometry *curves_orig_ = nullptr;
 
  Object *surface_ob_eval_ = nullptr;
  Mesh *surface_eval_ = nullptr;
  Span<float3> surface_positions_eval_;
  Span<int> surface_corner_verts_eval_;
  Span<int3> surface_corner_tris_eval_;
  VArraySpan<float2> surface_uv_map_eval_;
  bke::BVHTreeFromMesh surface_bvh_eval_;
 
  CurvesSculpt *curves_sculpt_ = nullptr;
  const Brush *brush_ = nullptr;
  const BrushCurvesSculptSettings *brush_settings_ = nullptr;
  int add_amount_;
  bool use_front_face_;
 
  float brush_radius_re_;
  float2 brush_pos_re_;
 
  CurvesSurfaceTransforms transforms_;
 
  AddOperationExecutor(const bContext &C) : ctx_(C) {}
 
  void execute(AddOperation &self, const bContext &C, const StrokeExtension &stroke_extension)
  {
    self_ = &self;
    curves_ob_orig_ = CTX_data_active_object(&C);
 
    curves_id_orig_ = static_cast<Curves *>(curves_ob_orig_->data);
    curves_orig_ = &curves_id_orig_->geometry.wrap();
 
    if (curves_id_orig_->surface == nullptr || curves_id_orig_->surface->type != OB_MESH) {
      report_missing_surface(stroke_extension.reports);
      return;
    }
 
    transforms_ = CurvesSurfaceTransforms(*curves_ob_orig_, curves_id_orig_->surface);
 
    Object &surface_ob_orig = *curves_id_orig_->surface;
    const Mesh &surface_orig = *static_cast<const Mesh *>(surface_ob_orig.data);
    if (surface_orig.faces_num == 0) {
      report_empty_original_surface(stroke_extension.reports);
      return;
    }
 
    surface_ob_eval_ = DEG_get_evaluated(ctx_.depsgraph, &surface_ob_orig);
    if (surface_ob_eval_ == nullptr) {
      return;
    }
    surface_eval_ = BKE_object_get_evaluated_mesh(surface_ob_eval_);
    if (surface_eval_->faces_num == 0) {
      report_empty_evaluated_surface(stroke_extension.reports);
      return;
    }
    surface_positions_eval_ = surface_eval_->vert_positions();
    surface_corner_verts_eval_ = surface_eval_->corner_verts();
    surface_corner_tris_eval_ = surface_eval_->corner_tris();
    surface_bvh_eval_ = surface_eval_->bvh_corner_tris();
 
    curves_sculpt_ = ctx_.scene->toolsettings->curves_sculpt;
    brush_ = BKE_paint_brush_for_read(&curves_sculpt_->paint);
    brush_settings_ = brush_->curves_sculpt_settings;
    brush_radius_re_ = brush_radius_get(curves_sculpt_->paint, *brush_, stroke_extension);
    brush_pos_re_ = stroke_extension.mouse_position;
 
    use_front_face_ = brush_->flag & BRUSH_FRONTFACE;
    const eBrushFalloffShape falloff_shape = eBrushFalloffShape(brush_->falloff_shape);
    add_amount_ = std::max(0, brush_settings_->add_amount);
 
    if (add_amount_ == 0) {
      return;
    }
 
    /* Find UV map. */
    VArraySpan<float2> surface_uv_map;
    if (curves_id_orig_->surface_uv_map != nullptr) {
      surface_uv_map = *surface_orig.attributes().lookup<float2>(curves_id_orig_->surface_uv_map,
                                                                 bke::AttrDomain::Corner);
      surface_uv_map_eval_ = *surface_eval_->attributes().lookup<float2>(
          curves_id_orig_->surface_uv_map, bke::AttrDomain::Corner);
    }
 
    if (surface_uv_map.is_empty()) {
      report_missing_uv_map_on_original_surface(stroke_extension.reports);
      return;
    }
    if (surface_uv_map_eval_.is_empty()) {
      report_missing_uv_map_on_evaluated_surface(stroke_extension.reports);
      return;
    }
 
    RandomNumberGenerator rng = RandomNumberGenerator::from_random_seed();
 
    /* Sample points on the surface using one of multiple strategies. */
    Vector<float2> sampled_uvs;
    if (add_amount_ == 1) {
      this->sample_in_center_with_symmetry(sampled_uvs);
    }
    else if (falloff_shape == PAINT_FALLOFF_SHAPE_TUBE) {
      this->sample_projected_with_symmetry(rng, sampled_uvs);
    }
    else if (falloff_shape == PAINT_FALLOFF_SHAPE_SPHERE) {
      this->sample_spherical_with_symmetry(rng, sampled_uvs);
    }
    else {
      BLI_assert_unreachable();
    }
 
    if (sampled_uvs.is_empty()) {
      /* No new points have been added. */
      return;
    }
 
    const Span<int3> surface_corner_tris_orig = surface_orig.corner_tris();
    const Span<float3> corner_normals_su = surface_orig.corner_normals();
    const geometry::ReverseUVSampler reverse_uv_sampler{surface_uv_map, surface_corner_tris_orig};
 
    geometry::AddCurvesOnMeshInputs add_inputs;
    add_inputs.uvs = sampled_uvs;
    add_inputs.interpolate_length = brush_settings_->flag &
                                    BRUSH_CURVES_SCULPT_FLAG_INTERPOLATE_LENGTH;
    add_inputs.interpolate_radius = brush_settings_->flag &
                                    BRUSH_CURVES_SCULPT_FLAG_INTERPOLATE_RADIUS;
    add_inputs.interpolate_shape = brush_settings_->flag &
                                   BRUSH_CURVES_SCULPT_FLAG_INTERPOLATE_SHAPE;
    add_inputs.interpolate_point_count = brush_settings_->flag &
                                         BRUSH_CURVES_SCULPT_FLAG_INTERPOLATE_POINT_COUNT;
    add_inputs.interpolate_resolution = curves_orig_->attributes().contains("resolution");
    add_inputs.fallback_curve_length = brush_settings_->curve_length;
    add_inputs.fallback_curve_radius = brush_settings_->curve_radius;
    add_inputs.fallback_point_count = std::max(2, brush_settings_->points_per_curve);
    add_inputs.transforms = &transforms_;
    add_inputs.surface_corner_tris = surface_corner_tris_orig;
    add_inputs.reverse_uv_sampler = &reverse_uv_sampler;
    add_inputs.surface = &surface_orig;
    add_inputs.corner_normals_su = corner_normals_su;
 
    if (add_inputs.interpolate_length || add_inputs.interpolate_radius ||
        add_inputs.interpolate_shape || add_inputs.interpolate_point_count ||
        add_inputs.interpolate_resolution)
    {
      this->ensure_curve_roots_kdtree();
      add_inputs.old_roots_kdtree = self_->curve_roots_kdtree_;
    }
 
    const geometry::AddCurvesOnMeshOutputs add_outputs = geometry::add_curves_on_mesh(
        *curves_orig_, add_inputs);
    bke::MutableAttributeAccessor attributes = curves_orig_->attributes_for_write();
    if (bke::GSpanAttributeWriter selection = attributes.lookup_for_write_span(".selection")) {
      curves::fill_selection_true(selection.span.slice(selection.domain == bke::AttrDomain::Point ?
                                                           add_outputs.new_points_range :
                                                           add_outputs.new_curves_range));
      selection.finish();
    }
    if (U.uiflag & USER_ORBIT_SELECTION) {
      if (const std::optional<Bounds<float3>> center_cu = bounds::min_max(
              curves_orig_->positions().slice(add_outputs.new_points_range)))
      {
        remember_stroke_position(
            *curves_sculpt_,
            math::transform_point(transforms_.curves_to_world, center_cu->center()));
      }
    }
 
    if (add_outputs.uv_error) {
      report_invalid_uv_map(stroke_extension.reports);
    }
 
    DEG_id_tag_update(&curves_id_orig_->id, ID_RECALC_GEOMETRY);
    WM_main_add_notifier(NC_GEOM | ND_DATA, &curves_id_orig_->id);
    ED_region_tag_redraw(ctx_.region);
  }

  void sample_in_center_with_symmetry(Vector<float2> &r_sampled_uvs)
  {
    float3 ray_start_wo, ray_end_wo;
    ED_view3d_win_to_segment_clipped(
        ctx_.depsgraph, ctx_.region, ctx_.v3d, brush_pos_re_, ray_start_wo, ray_end_wo, true);
    const float3 ray_start_cu = math::transform_point(transforms_.world_to_curves, ray_start_wo);
    const float3 ray_end_cu = math::transform_point(transforms_.world_to_curves, ray_end_wo);
 
    const Vector<float4x4> symmetry_brush_transforms = get_symmetry_brush_transforms(
        eCurvesSymmetryType(curves_id_orig_->symmetry));
 
    for (const float4x4 &brush_transform : symmetry_brush_transforms) {
      const float4x4 transform = transforms_.curves_to_surface * brush_transform;
      this->sample_in_center(r_sampled_uvs,
                             math::transform_point(transform, ray_start_cu),
                             math::transform_point(transform, ray_end_cu));
    }
  }
 
  void sample_in_center(Vector<float2> &r_sampled_uvs,
                        const float3 &ray_start_su,
                        const float3 &ray_end_su)
  {
    const float3 ray_direction_su = math::normalize(ray_end_su - ray_start_su);
 
    BVHTreeRayHit ray_hit;
    ray_hit.dist = FLT_MAX;
    ray_hit.index = -1;
    BLI_bvhtree_ray_cast(surface_bvh_eval_.tree,
                         ray_start_su,
                         ray_direction_su,
                         0.0f,
                         &ray_hit,
                         surface_bvh_eval_.raycast_callback,
                         &surface_bvh_eval_);
 
    if (ray_hit.index == -1) {
      return;
    }
 
    const int tri_index = ray_hit.index;
    const int3 &tri = surface_corner_tris_eval_[tri_index];
    const float3 brush_pos_su = ray_hit.co;
    const float3 bary_coords = bke::mesh_surface_sample::compute_bary_coord_in_triangle(
        surface_positions_eval_, surface_corner_verts_eval_, tri, brush_pos_su);
 
    const float2 uv = bke::mesh_surface_sample::sample_corner_attribute_with_bary_coords(
        bary_coords, tri, surface_uv_map_eval_);
    r_sampled_uvs.append(uv);
  }

  void sample_projected_with_symmetry(RandomNumberGenerator &rng, Vector<float2> &r_sampled_uvs)
  {
    const Vector<float4x4> symmetry_brush_transforms = get_symmetry_brush_transforms(
        eCurvesSymmetryType(curves_id_orig_->symmetry));
    for (const float4x4 &brush_transform : symmetry_brush_transforms) {
      this->sample_projected(rng, r_sampled_uvs, brush_transform);
    }
  }
 
  void sample_projected(RandomNumberGenerator &rng,
                        Vector<float2> &r_sampled_uvs,
                        const float4x4 &brush_transform)
  {
    const int old_amount = r_sampled_uvs.size();
    const int max_iterations = 100;
    int current_iteration = 0;
    while (r_sampled_uvs.size() < old_amount + add_amount_) {
      if (current_iteration++ >= max_iterations) {
        break;
      }
      Vector<float3> bary_coords;
      Vector<int> tri_indices;
      Vector<float3> positions_su;
 
      const int missing_amount = add_amount_ + old_amount - r_sampled_uvs.size();
      const int new_points = bke::mesh_surface_sample::sample_surface_points_projected(
          rng,
          *surface_eval_,
          surface_bvh_eval_,
          brush_pos_re_,
          brush_radius_re_,
          [&](const float2 &pos_re, float3 &r_start_su, float3 &r_end_su) {
            float3 start_wo, end_wo;
            ED_view3d_win_to_segment_clipped(
                ctx_.depsgraph, ctx_.region, ctx_.v3d, pos_re, start_wo, end_wo, true);
            const float3 start_cu = math::transform_point(transforms_.world_to_curves, start_wo);
            const float3 start_cu_tx = math::transform_point(brush_transform, start_cu);
            const float3 end_cu = math::transform_point(transforms_.world_to_curves, end_wo);
            const float3 end_cu_tx = math::transform_point(brush_transform, end_cu);
            r_start_su = math::transform_point(transforms_.curves_to_surface, start_cu_tx);
            r_end_su = math::transform_point(transforms_.curves_to_surface, end_cu_tx);
          },
          use_front_face_,
          add_amount_,
          missing_amount,
          bary_coords,
          tri_indices,
          positions_su);
 
      for (const int i : IndexRange(new_points)) {
        const float2 uv = bke::mesh_surface_sample::sample_corner_attribute_with_bary_coords(
            bary_coords[i], surface_corner_tris_eval_[tri_indices[i]], surface_uv_map_eval_);
        r_sampled_uvs.append(uv);
      }
    }
  }

  void sample_spherical_with_symmetry(RandomNumberGenerator &rng, Vector<float2> &r_sampled_uvs)
  {
    const std::optional<CurvesBrush3D> brush_3d = sample_curves_surface_3d_brush(*ctx_.depsgraph,
                                                                                 *ctx_.region,
                                                                                 *ctx_.v3d,
                                                                                 transforms_,
                                                                                 surface_bvh_eval_,
                                                                                 brush_pos_re_,
                                                                                 brush_radius_re_);
    if (!brush_3d.has_value()) {
      return;
    }
 
    float3 view_ray_start_wo, view_ray_end_wo;
    ED_view3d_win_to_segment_clipped(ctx_.depsgraph,
                                     ctx_.region,
                                     ctx_.v3d,
                                     brush_pos_re_,
                                     view_ray_start_wo,
                                     view_ray_end_wo,
                                     true);
 
    const float3 view_ray_start_cu = math::transform_point(transforms_.world_to_curves,
                                                           view_ray_start_wo);
    const float3 view_ray_end_cu = math::transform_point(transforms_.world_to_curves,
                                                         view_ray_end_wo);
 
    const Vector<float4x4> symmetry_brush_transforms = get_symmetry_brush_transforms(
        eCurvesSymmetryType(curves_id_orig_->symmetry));
    for (const float4x4 &brush_transform : symmetry_brush_transforms) {
      const float4x4 transform = transforms_.curves_to_surface * brush_transform;
 
      const float3 brush_pos_su = math::transform_point(transform, brush_3d->position_cu);
      const float3 view_direction_su = math::normalize(
          math::transform_point(transform, view_ray_end_cu) -
          math::transform_point(transform, view_ray_start_cu));
      const float brush_radius_su = transform_brush_radius(
          transform, brush_3d->position_cu, brush_3d->radius_cu);
 
      this->sample_spherical(rng, r_sampled_uvs, brush_pos_su, brush_radius_su, view_direction_su);
    }
  }
 
  void sample_spherical(RandomNumberGenerator &rng,
                        Vector<float2> &r_sampled_uvs,
                        const float3 &brush_pos_su,
                        const float brush_radius_su,
                        const float3 &view_direction_su)
  {
    const float brush_radius_sq_su = pow2f(brush_radius_su);
 
    /* Find surface triangles within brush radius. */
    Vector<int> selected_tri_indices;
    if (use_front_face_) {
      BLI_bvhtree_range_query_cpp(
          *surface_bvh_eval_.tree,
          brush_pos_su,
          brush_radius_su,
          [&](const int index, const float3 & /*co*/, const float /*dist_sq*/) {
            const int3 &tri = surface_corner_tris_eval_[index];
            const float3 &v0_su = surface_positions_eval_[surface_corner_verts_eval_[tri[0]]];
            const float3 &v1_su = surface_positions_eval_[surface_corner_verts_eval_[tri[1]]];
            const float3 &v2_su = surface_positions_eval_[surface_corner_verts_eval_[tri[2]]];
            float3 normal_su;
            normal_tri_v3(normal_su, v0_su, v1_su, v2_su);
            if (math::dot(normal_su, view_direction_su) >= 0.0f) {
              return;
            }
            selected_tri_indices.append(index);
          });
    }
    else {
      BLI_bvhtree_range_query_cpp(
          *surface_bvh_eval_.tree,
          brush_pos_su,
          brush_radius_su,
          [&](const int index, const float3 & /*co*/, const float /*dist_sq*/) {
            selected_tri_indices.append(index);
          });
    }
 
    /* Density used for sampling points. This does not have to be exact, because the loop below
     * automatically runs until enough samples have been found. If too many samples are found, some
     * will be discarded afterwards. */
    const float brush_plane_area_su = M_PI * brush_radius_sq_su;
    const float approximate_density_su = add_amount_ / brush_plane_area_su;
 
    /* Usually one or two iterations should be enough. */
    const int max_iterations = 5;
    int current_iteration = 0;
 
    const int old_amount = r_sampled_uvs.size();
    while (r_sampled_uvs.size() < old_amount + add_amount_) {
      if (current_iteration++ >= max_iterations) {
        break;
      }
      Vector<float3> bary_coords;
      Vector<int> tri_indices;
      Vector<float3> positions_su;
      const int new_points = bke::mesh_surface_sample::sample_surface_points_spherical(
          rng,
          *surface_eval_,
          selected_tri_indices,
          brush_pos_su,
          brush_radius_su,
          approximate_density_su,
          bary_coords,
          tri_indices,
          positions_su);
      for (const int i : IndexRange(new_points)) {
        const float2 uv = bke::mesh_surface_sample::sample_corner_attribute_with_bary_coords(
            bary_coords[i], surface_corner_tris_eval_[tri_indices[i]], surface_uv_map_eval_);
        r_sampled_uvs.append(uv);
      }
    }
 
    /* Remove samples when there are too many. */
    while (r_sampled_uvs.size() > old_amount + add_amount_) {
      const int index_to_remove = rng.get_int32(add_amount_) + old_amount;
      r_sampled_uvs.remove_and_reorder(index_to_remove);
    }
  }
 
  void ensure_curve_roots_kdtree()
  {
    if (self_->curve_roots_kdtree_ == nullptr) {
      self_->curve_roots_kdtree_ = BLI_kdtree_3d_new(curves_orig_->curves_num());
      const Span<int> offsets = curves_orig_->offsets();
      const Span<float3> positions = curves_orig_->positions();
      for (const int curve_i : curves_orig_->curves_range()) {
        BLI_kdtree_3d_insert(self_->curve_roots_kdtree_, curve_i, positions[offsets[curve_i]]);
      }
      BLI_kdtree_3d_balance(self_->curve_roots_kdtree_);
    }
  }
};
 
void AddOperation::on_stroke_extended(const bContext &C, const StrokeExtension &stroke_extension)
{
  AddOperationExecutor executor{C};
  executor.execute(*this, C, stroke_extension);
}
 
std::unique_ptr<CurvesSculptStrokeOperation> new_add_operation()
{
  return std::make_unique<AddOperation>();
}
 
}  // namespace blender::ed::sculpt_paint