diff options
author | Jacques Lucke <jacques@blender.org> | 2022-03-21 20:54:31 +0300 |
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committer | Jacques Lucke <jacques@blender.org> | 2022-03-21 20:59:03 +0300 |
commit | a58be397e2bfbefa0324dbe861b018dd2784ee0d (patch) | |
tree | 4ad14d927e10974e95d3be0a32436888a5260a91 /source/blender/editors/sculpt_paint/curves_sculpt_add.cc | |
parent | f8d19ec5a3d8c14d0c71464867ad1af10ee50eb5 (diff) |
Curves: new Add brush
This adds a new Add brush for the new curves object type in sculpt mode.
The brush is used to insert new curves (typically hair) on the surface object.
Supported features:
* Add single curve exactly at the cursor position when `Add Amount` is 1.
* Front faces only.
* Independent interpolate shape and interpolate length settings.
* Smooth and flat shading affects curve shape interpolation.
* Spherical and projection brush.
This also adds the `surface_triangle_index` and `surface_triangle_coordinate`
attributes. Those store information about what position on the surface each
added curve is attached to:
* `surface_triangle_index` (`int`): Index of the internal triangle that a curve
is attached to. `-1` when the curve is not attached to the surface.
* `surface_triangle_coordinate` (`float2`): First two numbers of a barycentric
coordinate that reference a specific position within the triangle.
Ref T96444.
Differential Revision: https://developer.blender.org/D14340
Diffstat (limited to 'source/blender/editors/sculpt_paint/curves_sculpt_add.cc')
-rw-r--r-- | source/blender/editors/sculpt_paint/curves_sculpt_add.cc | 792 |
1 files changed, 792 insertions, 0 deletions
diff --git a/source/blender/editors/sculpt_paint/curves_sculpt_add.cc b/source/blender/editors/sculpt_paint/curves_sculpt_add.cc new file mode 100644 index 00000000000..e57a6e43983 --- /dev/null +++ b/source/blender/editors/sculpt_paint/curves_sculpt_add.cc @@ -0,0 +1,792 @@ +/* SPDX-License-Identifier: GPL-2.0-or-later */ + +#include <algorithm> + +#include "curves_sculpt_intern.hh" + +#include "BLI_float4x4.hh" +#include "BLI_kdtree.h" +#include "BLI_rand.hh" +#include "BLI_vector.hh" + +#include "PIL_time.h" + +#include "DEG_depsgraph.h" + +#include "BKE_attribute_math.hh" +#include "BKE_brush.h" +#include "BKE_bvhutils.h" +#include "BKE_context.h" +#include "BKE_curves.hh" +#include "BKE_mesh.h" +#include "BKE_mesh_runtime.h" +#include "BKE_paint.h" +#include "BKE_spline.hh" + +#include "DNA_brush_enums.h" +#include "DNA_brush_types.h" +#include "DNA_curves_types.h" +#include "DNA_mesh_types.h" +#include "DNA_meshdata_types.h" +#include "DNA_object_types.h" +#include "DNA_screen_types.h" +#include "DNA_space_types.h" + +#include "ED_screen.h" +#include "ED_view3d.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. + * su: Local space of the surface object. + * wo: World space. + * re: 2D coordinates within the region. + */ + +namespace blender::ed::sculpt_paint { + +using bke::CurvesGeometry; + +class AddOperation : public CurvesSculptStrokeOperation { + private: + /** Used when some data should be interpolated from existing curves. */ + KDTree_3d *curve_roots_kdtree_ = nullptr; + + friend struct AddOperationExecutor; + + public: + ~AddOperation() + { + if (curve_roots_kdtree_ != nullptr) { + BLI_kdtree_3d_free(curve_roots_kdtree_); + } + } + + void on_stroke_extended(bContext *C, const StrokeExtension &stroke_extension) override; +}; + +static void initialize_straight_curve_positions(const float3 &p1, + const float3 &p2, + MutableSpan<float3> r_positions) +{ + const float step = 1.0f / (float)(r_positions.size() - 1); + for (const int i : r_positions.index_range()) { + r_positions[i] = math::interpolate(p1, p2, i * step); + } +} + +/** + * Utility class that actually executes the update when the stroke is updated. That's useful + * because it avoids passing a very large number of parameters between functions. + */ +struct AddOperationExecutor { + AddOperation *self_ = nullptr; + Depsgraph *depsgraph_ = nullptr; + Scene *scene_ = nullptr; + Object *object_ = nullptr; + ARegion *region_ = nullptr; + View3D *v3d_ = nullptr; + Curves *curves_id_ = nullptr; + CurvesGeometry *curves_ = nullptr; + + Object *surface_ob_ = nullptr; + Mesh *surface_ = nullptr; + Span<MLoopTri> surface_looptris_; + Span<float3> corner_normals_su_; + + CurvesSculpt *curves_sculpt_ = nullptr; + Brush *brush_ = nullptr; + + float brush_radius_re_; + float2 brush_pos_re_; + + bool use_front_face_; + bool interpolate_length_; + bool interpolate_shape_; + bool use_interpolation_; + float new_curve_length_; + int add_amount_; + int points_per_curve_ = 8; + + /** Various matrices to convert between coordinate spaces. */ + float4x4 curves_to_world_mat_; + float4x4 world_to_curves_mat_; + float4x4 world_to_surface_mat_; + float4x4 surface_to_world_mat_; + float4x4 surface_to_curves_mat_; + float4x4 surface_to_curves_normal_mat_; + + BVHTreeFromMesh surface_bvh_; + + int tot_old_curves_; + int tot_old_points_; + + struct AddedPoints { + Vector<float3> positions_cu; + Vector<float3> bary_coords; + Vector<int> looptri_indices; + }; + + void execute(AddOperation &self, bContext *C, const StrokeExtension &stroke_extension) + { + self_ = &self; + depsgraph_ = CTX_data_depsgraph_pointer(C); + scene_ = CTX_data_scene(C); + object_ = CTX_data_active_object(C); + region_ = CTX_wm_region(C); + v3d_ = CTX_wm_view3d(C); + + curves_id_ = static_cast<Curves *>(object_->data); + curves_ = &CurvesGeometry::wrap(curves_id_->geometry); + + if (curves_id_->surface == nullptr || curves_id_->surface->type != OB_MESH) { + return; + } + + curves_to_world_mat_ = object_->obmat; + world_to_curves_mat_ = curves_to_world_mat_.inverted(); + + surface_ob_ = curves_id_->surface; + surface_ = static_cast<Mesh *>(surface_ob_->data); + surface_to_world_mat_ = surface_ob_->obmat; + world_to_surface_mat_ = surface_to_world_mat_.inverted(); + surface_to_curves_mat_ = world_to_curves_mat_ * surface_to_world_mat_; + surface_to_curves_normal_mat_ = surface_to_curves_mat_.inverted().transposed(); + + if (!CustomData_has_layer(&surface_->ldata, CD_NORMAL)) { + BKE_mesh_calc_normals_split(surface_); + } + corner_normals_su_ = { + reinterpret_cast<const float3 *>(CustomData_get_layer(&surface_->ldata, CD_NORMAL)), + surface_->totloop}; + + curves_sculpt_ = scene_->toolsettings->curves_sculpt; + brush_ = BKE_paint_brush(&curves_sculpt_->paint); + brush_radius_re_ = BKE_brush_size_get(scene_, brush_); + brush_pos_re_ = stroke_extension.mouse_position; + + use_front_face_ = brush_->flag & BRUSH_FRONTFACE; + const eBrushFalloffShape falloff_shape = static_cast<eBrushFalloffShape>( + brush_->falloff_shape); + add_amount_ = std::max(0, brush_->curves_sculpt_settings->add_amount); + interpolate_length_ = curves_sculpt_->flag & CURVES_SCULPT_FLAG_INTERPOLATE_LENGTH; + interpolate_shape_ = curves_sculpt_->flag & CURVES_SCULPT_FLAG_INTERPOLATE_SHAPE; + use_interpolation_ = interpolate_length_ || interpolate_shape_; + new_curve_length_ = curves_sculpt_->curve_length; + + tot_old_curves_ = curves_->curves_size(); + tot_old_points_ = curves_->points_size(); + + if (add_amount_ == 0) { + return; + } + + RandomNumberGenerator rng{(uint32_t)(PIL_check_seconds_timer() * 1000000.0f)}; + + BKE_bvhtree_from_mesh_get(&surface_bvh_, surface_, BVHTREE_FROM_LOOPTRI, 2); + BLI_SCOPED_DEFER([&]() { free_bvhtree_from_mesh(&surface_bvh_); }); + + surface_looptris_ = {BKE_mesh_runtime_looptri_ensure(surface_), + BKE_mesh_runtime_looptri_len(surface_)}; + + /* Sample points on the surface using one of multiple strategies. */ + AddedPoints added_points; + if (add_amount_ == 1) { + this->sample_in_center(added_points); + } + else if (falloff_shape == PAINT_FALLOFF_SHAPE_TUBE) { + this->sample_projected(rng, added_points); + } + else if (falloff_shape == PAINT_FALLOFF_SHAPE_SPHERE) { + this->sample_spherical(rng, added_points); + } + else { + BLI_assert_unreachable(); + } + + if (added_points.bary_coords.is_empty()) { + /* No new points have been added. */ + return; + } + + if (use_interpolation_) { + this->ensure_curve_roots_kdtree(); + } + + const int tot_added_curves = added_points.bary_coords.size(); + const int tot_added_points = tot_added_curves * points_per_curve_; + + curves_->resize(curves_->points_size() + tot_added_points, + curves_->curves_size() + tot_added_curves); + + threading::parallel_invoke([&]() { this->initialize_curve_offsets(tot_added_curves); }, + [&]() { this->initialize_attributes(added_points); }); + + DEG_id_tag_update(&curves_id_->id, ID_RECALC_GEOMETRY); + ED_region_tag_redraw(region_); + } + + float3 get_bary_coords(const Mesh &mesh, const MLoopTri &looptri, const float3 position) const + { + const float3 &v0 = mesh.mvert[mesh.mloop[looptri.tri[0]].v].co; + const float3 &v1 = mesh.mvert[mesh.mloop[looptri.tri[1]].v].co; + const float3 &v2 = mesh.mvert[mesh.mloop[looptri.tri[2]].v].co; + float3 bary_coords; + interp_weights_tri_v3(bary_coords, v0, v1, v2, position); + return bary_coords; + } + + /** + * Sample a single point exactly at the mouse position. + */ + void sample_in_center(AddedPoints &r_added_points) + { + float3 ray_start_wo, ray_end_wo; + ED_view3d_win_to_segment_clipped( + depsgraph_, region_, v3d_, brush_pos_re_, ray_start_wo, ray_end_wo, true); + const float3 ray_start_su = world_to_surface_mat_ * ray_start_wo; + const float3 ray_end_su = world_to_surface_mat_ * ray_end_wo; + 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_.tree, + ray_start_su, + ray_direction_su, + 0.0f, + &ray_hit, + surface_bvh_.raycast_callback, + &surface_bvh_); + + if (ray_hit.index == -1) { + return; + } + + const int looptri_index = ray_hit.index; + const float3 brush_pos_su = ray_hit.co; + const float3 bary_coords = this->get_bary_coords( + *surface_, surface_looptris_[looptri_index], brush_pos_su); + + const float3 brush_pos_cu = surface_to_curves_mat_ * brush_pos_su; + + r_added_points.positions_cu.append(brush_pos_cu); + r_added_points.bary_coords.append(bary_coords); + r_added_points.looptri_indices.append(looptri_index); + } + + /** + * Sample points by shooting rays within the brush radius in the 3D view. + */ + void sample_projected(RandomNumberGenerator &rng, AddedPoints &r_added_points) + { + const int max_iterations = std::max(100'000, add_amount_ * 10); + int current_iteration = 0; + while (r_added_points.bary_coords.size() < add_amount_) { + if (current_iteration++ >= max_iterations) { + break; + } + + const float r = brush_radius_re_ * std::sqrt(rng.get_float()); + const float angle = rng.get_float() * 2.0f * M_PI; + const float2 pos_re = brush_pos_re_ + r * float2(std::cos(angle), std::sin(angle)); + + float3 ray_start_wo, ray_end_wo; + ED_view3d_win_to_segment_clipped( + depsgraph_, region_, v3d_, pos_re, ray_start_wo, ray_end_wo, true); + const float3 ray_start_su = world_to_surface_mat_ * ray_start_wo; + const float3 ray_end_su = world_to_surface_mat_ * ray_end_wo; + 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_.tree, + ray_start_su, + ray_direction_su, + 0.0f, + &ray_hit, + surface_bvh_.raycast_callback, + &surface_bvh_); + + if (ray_hit.index == -1) { + continue; + } + + if (use_front_face_) { + const float3 normal_su = ray_hit.no; + if (math::dot(ray_direction_su, normal_su) >= 0.0f) { + continue; + } + } + + const int looptri_index = ray_hit.index; + const float3 pos_su = ray_hit.co; + + const float3 bary_coords = this->get_bary_coords( + *surface_, surface_looptris_[looptri_index], pos_su); + + const float3 pos_cu = surface_to_curves_mat_ * pos_su; + + r_added_points.positions_cu.append(pos_cu); + r_added_points.bary_coords.append(bary_coords); + r_added_points.looptri_indices.append(looptri_index); + } + } + + /** + * Sample points in a 3D sphere around the surface position that the mouse hovers over. + */ + void sample_spherical(RandomNumberGenerator &rng, AddedPoints &r_added_points) + { + /* Find ray that starts in the center of the brush. */ + float3 brush_ray_start_wo, brush_ray_end_wo; + ED_view3d_win_to_segment_clipped( + depsgraph_, region_, v3d_, brush_pos_re_, brush_ray_start_wo, brush_ray_end_wo, true); + const float3 brush_ray_start_su = world_to_surface_mat_ * brush_ray_start_wo; + const float3 brush_ray_end_su = world_to_surface_mat_ * brush_ray_end_wo; + const float3 brush_ray_direction_su = math::normalize(brush_ray_end_su - brush_ray_start_su); + + /* Find ray that starts on the boundary of the brush. That is used to compute the brush radius + * in 3D. */ + float3 brush_radius_ray_start_wo, brush_radius_ray_end_wo; + ED_view3d_win_to_segment_clipped(depsgraph_, + region_, + v3d_, + brush_pos_re_ + float2(brush_radius_re_, 0), + brush_radius_ray_start_wo, + brush_radius_ray_end_wo, + true); + const float3 brush_radius_ray_start_su = world_to_surface_mat_ * brush_radius_ray_start_wo; + const float3 brush_radius_ray_end_su = world_to_surface_mat_ * brush_radius_ray_end_wo; + + BVHTreeRayHit ray_hit; + ray_hit.dist = FLT_MAX; + ray_hit.index = -1; + BLI_bvhtree_ray_cast(surface_bvh_.tree, + brush_ray_start_su, + brush_ray_direction_su, + 0.0f, + &ray_hit, + surface_bvh_.raycast_callback, + &surface_bvh_); + + if (ray_hit.index == -1) { + return; + } + + /* Compute brush radius. */ + const float3 brush_pos_su = ray_hit.co; + const float brush_radius_su = dist_to_line_v3( + brush_pos_su, brush_radius_ray_start_su, brush_radius_ray_end_su); + const float brush_radius_sq_su = pow2f(brush_radius_su); + + /* Find surface triangles within brush radius. */ + Vector<int> looptri_indices; + if (use_front_face_) { + BLI_bvhtree_range_query_cpp( + *surface_bvh_.tree, + brush_pos_su, + brush_radius_su, + [&](const int index, const float3 &UNUSED(co), const float UNUSED(dist_sq)) { + const MLoopTri &looptri = surface_looptris_[index]; + const float3 v0_su = surface_->mvert[surface_->mloop[looptri.tri[0]].v].co; + const float3 v1_su = surface_->mvert[surface_->mloop[looptri.tri[1]].v].co; + const float3 v2_su = surface_->mvert[surface_->mloop[looptri.tri[2]].v].co; + float3 normal_su; + normal_tri_v3(normal_su, v0_su, v1_su, v2_su); + if (math::dot(normal_su, brush_ray_direction_su) >= 0.0f) { + return; + } + looptri_indices.append(index); + }); + } + else { + BLI_bvhtree_range_query_cpp( + *surface_bvh_.tree, + brush_pos_su, + brush_radius_su, + [&](const int index, const float3 &UNUSED(co), const float UNUSED(dist_sq)) { + looptri_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; + + /* Used for switching between two triangle sampling strategies. */ + const float area_threshold = brush_plane_area_su; + + /* Usually one or two iterations should be enough. */ + const int max_iterations = 5; + int current_iteration = 0; + + while (r_added_points.bary_coords.size() < add_amount_) { + if (current_iteration++ >= max_iterations) { + break; + } + + for (const int looptri_index : looptri_indices) { + const MLoopTri &looptri = surface_looptris_[looptri_index]; + + const float3 v0_su = surface_->mvert[surface_->mloop[looptri.tri[0]].v].co; + const float3 v1_su = surface_->mvert[surface_->mloop[looptri.tri[1]].v].co; + const float3 v2_su = surface_->mvert[surface_->mloop[looptri.tri[2]].v].co; + + const float looptri_area_su = area_tri_v3(v0_su, v1_su, v2_su); + + if (looptri_area_su < area_threshold) { + /* The triangle is small compared to the brush radius. Sample by generating random + * barycentric coordinates. */ + const int amount = rng.round_probabilistic(approximate_density_su * looptri_area_su); + for ([[maybe_unused]] const int i : IndexRange(amount)) { + const float3 bary_coord = rng.get_barycentric_coordinates(); + const float3 point_pos_su = attribute_math::mix3(bary_coord, v0_su, v1_su, v2_su); + const float distance_to_brush_sq_su = math::distance_squared(point_pos_su, + brush_pos_su); + if (distance_to_brush_sq_su > brush_radius_sq_su) { + continue; + } + + r_added_points.bary_coords.append(bary_coord); + r_added_points.looptri_indices.append(looptri_index); + r_added_points.positions_cu.append(surface_to_curves_mat_ * point_pos_su); + } + } + else { + /* The triangle is large compared to the brush radius. Sample by generating random points + * on the triangle plane within the brush radius. */ + float3 normal_su; + normal_tri_v3(normal_su, v0_su, v1_su, v2_su); + + float3 brush_pos_proj_su = brush_pos_su; + project_v3_plane(brush_pos_proj_su, normal_su, v0_su); + + const float proj_distance_sq_su = math::distance_squared(brush_pos_proj_su, + brush_pos_su); + const float brush_radius_factor_sq = 1.0f - + std::min(1.0f, + proj_distance_sq_su / brush_radius_sq_su); + const float radius_proj_sq_su = brush_radius_sq_su * brush_radius_factor_sq; + const float radius_proj_su = std::sqrt(radius_proj_sq_su); + const float circle_area_su = M_PI * radius_proj_su; + + const int amount = rng.round_probabilistic(approximate_density_su * circle_area_su); + + const float3 axis_1_su = math::normalize(v1_su - v0_su) * radius_proj_su; + const float3 axis_2_su = math::normalize(math::cross( + axis_1_su, math::cross(axis_1_su, v2_su - v0_su))) * + radius_proj_su; + + for ([[maybe_unused]] const int i : IndexRange(amount)) { + const float r = std::sqrt(rng.get_float()); + const float angle = rng.get_float() * 2.0f * M_PI; + const float x = r * std::cos(angle); + const float y = r * std::sin(angle); + const float3 point_pos_su = brush_pos_proj_su + axis_1_su * x + axis_2_su * y; + if (!isect_point_tri_prism_v3(point_pos_su, v0_su, v1_su, v2_su)) { + /* Sampled point is not in the triangle. */ + continue; + } + + float3 bary_coord; + interp_weights_tri_v3(bary_coord, v0_su, v1_su, v2_su, point_pos_su); + + r_added_points.bary_coords.append(bary_coord); + r_added_points.looptri_indices.append(looptri_index); + r_added_points.positions_cu.append(surface_to_curves_mat_ * point_pos_su); + } + } + } + } + + /* Remove samples when there are too many. */ + while (r_added_points.bary_coords.size() > add_amount_) { + const int index_to_remove = rng.get_int32(r_added_points.bary_coords.size()); + r_added_points.bary_coords.remove_and_reorder(index_to_remove); + r_added_points.looptri_indices.remove_and_reorder(index_to_remove); + r_added_points.positions_cu.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_->curves_size()); + for (const int curve_i : curves_->curves_range()) { + const int root_point_i = curves_->offsets()[curve_i]; + const float3 &root_pos_cu = curves_->positions()[root_point_i]; + BLI_kdtree_3d_insert(self_->curve_roots_kdtree_, curve_i, root_pos_cu); + } + BLI_kdtree_3d_balance(self_->curve_roots_kdtree_); + } + } + + void initialize_curve_offsets(const int tot_added_curves) + { + MutableSpan<int> offsets = curves_->offsets(); + threading::parallel_for(IndexRange(tot_added_curves), 1024, [&](const IndexRange range) { + for (const int i : range) { + const int curve_i = tot_old_curves_ + i; + offsets[curve_i + 1] = tot_old_points_ + (i + 1) * points_per_curve_; + } + }); + } + + struct NeighborInfo { + /* Curve index of the neighbor. */ + int index; + /* The weights of all neighbors of a new curve add up to 1. */ + float weight; + }; + static constexpr int max_neighbors = 5; + using NeighborsVector = Vector<NeighborInfo, max_neighbors>; + + void initialize_attributes(const AddedPoints &added_points) + { + Array<NeighborsVector> neighbors_per_curve; + if (use_interpolation_) { + neighbors_per_curve = this->find_curve_neighbors(added_points); + } + + Array<float> new_lengths_cu(added_points.bary_coords.size()); + if (interpolate_length_) { + this->interpolate_lengths(neighbors_per_curve, new_lengths_cu); + } + else { + new_lengths_cu.fill(new_curve_length_); + } + + Array<float3> new_normals_su = this->compute_normals_for_added_curves_su(added_points); + this->initialize_surface_attachment(added_points); + + if (interpolate_shape_) { + this->initialize_position_with_interpolation( + added_points, neighbors_per_curve, new_normals_su, new_lengths_cu); + } + else { + this->initialize_position_without_interpolation( + added_points, new_lengths_cu, new_normals_su); + } + } + + Array<NeighborsVector> find_curve_neighbors(const AddedPoints &added_points) + { + const int tot_added_curves = added_points.bary_coords.size(); + Array<NeighborsVector> neighbors_per_curve(tot_added_curves); + threading::parallel_for(IndexRange(tot_added_curves), 128, [&](const IndexRange range) { + for (const int i : range) { + const float3 root_cu = added_points.positions_cu[i]; + std::array<KDTreeNearest_3d, max_neighbors> nearest_n; + const int found_neighbors = BLI_kdtree_3d_find_nearest_n( + self_->curve_roots_kdtree_, root_cu, nearest_n.data(), max_neighbors); + float tot_weight = 0.0f; + for (const int neighbor_i : IndexRange(found_neighbors)) { + KDTreeNearest_3d &nearest = nearest_n[neighbor_i]; + const float weight = 1.0f / std::max(nearest.dist, 0.00001f); + tot_weight += weight; + neighbors_per_curve[i].append({nearest.index, weight}); + } + /* Normalize weights. */ + for (NeighborInfo &neighbor : neighbors_per_curve[i]) { + neighbor.weight /= tot_weight; + } + } + }); + return neighbors_per_curve; + } + + void interpolate_lengths(const Span<NeighborsVector> neighbors_per_curve, + MutableSpan<float> r_lengths) + { + const Span<float3> positions_cu = curves_->positions(); + + threading::parallel_for(r_lengths.index_range(), 128, [&](const IndexRange range) { + for (const int added_curve_i : range) { + const Span<NeighborInfo> neighbors = neighbors_per_curve[added_curve_i]; + float length_sum = 0.0f; + for (const NeighborInfo &neighbor : neighbors) { + const IndexRange neighbor_points = curves_->range_for_curve(neighbor.index); + float neighbor_length = 0.0f; + const int tot_segments = neighbor_points.size() - 1; + for (const int segment_i : IndexRange(tot_segments)) { + const float3 &p1 = positions_cu[neighbor_points[segment_i]]; + const float3 &p2 = positions_cu[neighbor_points[segment_i] + 1]; + neighbor_length += math::distance(p1, p2); + } + length_sum += neighbor.weight * neighbor_length; + } + const float length = neighbors.is_empty() ? new_curve_length_ : length_sum; + r_lengths[added_curve_i] = length; + } + }); + } + + float3 compute_point_normal_su(const int looptri_index, const float3 &bary_coord) + { + const MLoopTri &looptri = surface_looptris_[looptri_index]; + const int l0 = looptri.tri[0]; + const int l1 = looptri.tri[1]; + const int l2 = looptri.tri[2]; + + const float3 &l0_normal_su = corner_normals_su_[l0]; + const float3 &l1_normal_su = corner_normals_su_[l1]; + const float3 &l2_normal_su = corner_normals_su_[l2]; + + const float3 normal_su = math::normalize( + attribute_math::mix3(bary_coord, l0_normal_su, l1_normal_su, l2_normal_su)); + return normal_su; + } + + Array<float3> compute_normals_for_added_curves_su(const AddedPoints &added_points) + { + Array<float3> normals_su(added_points.bary_coords.size()); + threading::parallel_for(normals_su.index_range(), 256, [&](const IndexRange range) { + for (const int i : range) { + const int looptri_index = added_points.looptri_indices[i]; + const float3 &bary_coord = added_points.bary_coords[i]; + normals_su[i] = this->compute_point_normal_su(looptri_index, bary_coord); + } + }); + return normals_su; + } + + void initialize_surface_attachment(const AddedPoints &added_points) + { + MutableSpan<int> surface_triangle_indices = curves_->surface_triangle_indices(); + MutableSpan<float2> surface_triangle_coords = curves_->surface_triangle_coords(); + threading::parallel_for( + added_points.bary_coords.index_range(), 1024, [&](const IndexRange range) { + for (const int i : range) { + const int curve_i = tot_old_curves_ + i; + surface_triangle_indices[curve_i] = added_points.looptri_indices[i]; + surface_triangle_coords[curve_i] = float2(added_points.bary_coords[i]); + } + }); + } + + /** + * Initialize new curves so that they are just a straight line in the normal direction. + */ + void initialize_position_without_interpolation(const AddedPoints &added_points, + const Span<float> lengths_cu, + const MutableSpan<float3> normals_su) + { + MutableSpan<float3> positions_cu = curves_->positions(); + + threading::parallel_for( + added_points.bary_coords.index_range(), 256, [&](const IndexRange range) { + for (const int i : range) { + const int first_point_i = tot_old_points_ + i * points_per_curve_; + const float3 &root_cu = added_points.positions_cu[i]; + const float length = lengths_cu[i]; + const float3 &normal_su = normals_su[i]; + const float3 normal_cu = math::normalize(surface_to_curves_normal_mat_ * normal_su); + const float3 tip_cu = root_cu + length * normal_cu; + + initialize_straight_curve_positions( + root_cu, tip_cu, positions_cu.slice(first_point_i, points_per_curve_)); + } + }); + } + + /** + * Use neighboring curves to determine the shape. + */ + void initialize_position_with_interpolation(const AddedPoints &added_points, + const Span<NeighborsVector> neighbors_per_curve, + const Span<float3> new_normals_su, + const Span<float> new_lengths_cu) + { + MutableSpan<float3> positions_cu = curves_->positions(); + const Span<int> surface_triangle_indices = curves_->surface_triangle_indices(); + const Span<float2> surface_triangle_coords = curves_->surface_triangle_coords(); + + threading::parallel_for( + added_points.bary_coords.index_range(), 256, [&](const IndexRange range) { + for (const int i : range) { + const Span<NeighborInfo> neighbors = neighbors_per_curve[i]; + + const float length_cu = new_lengths_cu[i]; + const float3 &normal_su = new_normals_su[i]; + const float3 normal_cu = math::normalize(surface_to_curves_normal_mat_ * normal_su); + + const float3 &root_cu = added_points.positions_cu[i]; + const int first_point_i = tot_old_points_ + i * points_per_curve_; + + if (neighbors.is_empty()) { + /* If there are no neighbors, just make a straight line. */ + const float3 tip_cu = root_cu + length_cu * normal_cu; + initialize_straight_curve_positions( + root_cu, tip_cu, positions_cu.slice(first_point_i, points_per_curve_)); + continue; + } + + positions_cu.slice(first_point_i, points_per_curve_).fill(root_cu); + + for (const NeighborInfo &neighbor : neighbors) { + const int neighbor_curve_i = neighbor.index; + const int neighbor_looptri_index = surface_triangle_indices[neighbor_curve_i]; + + float3 neighbor_bary_coord{surface_triangle_coords[neighbor_curve_i]}; + neighbor_bary_coord.z = 1.0f - neighbor_bary_coord.x - neighbor_bary_coord.y; + + const float3 neighbor_normal_su = this->compute_point_normal_su( + neighbor_looptri_index, neighbor_bary_coord); + const float3 neighbor_normal_cu = math::normalize(surface_to_curves_normal_mat_ * + neighbor_normal_su); + + /* The rotation matrix used to transform relative coordinates of the neighbor curve + * to the new curve. */ + float normal_rotation_cu[3][3]; + rotation_between_vecs_to_mat3(normal_rotation_cu, neighbor_normal_cu, normal_cu); + + const IndexRange neighbor_points = curves_->range_for_curve(neighbor_curve_i); + const float3 &neighbor_root_cu = positions_cu[neighbor_points[0]]; + + /* Use a temporary #PolySpline, because that's the easiest way to resample an + * existing curve right now. Resampling is necessary if the length of the new curve + * does not match the length of the neighbors or the number of handle points is + * different. */ + PolySpline neighbor_spline; + neighbor_spline.resize(neighbor_points.size()); + neighbor_spline.positions().copy_from(positions_cu.slice(neighbor_points)); + neighbor_spline.mark_cache_invalid(); + + const float neighbor_length_cu = neighbor_spline.length(); + const float length_factor = std::min(1.0f, length_cu / neighbor_length_cu); + + const float resample_factor = (1.0f / (points_per_curve_ - 1.0f)) * length_factor; + for (const int j : IndexRange(points_per_curve_)) { + const Spline::LookupResult lookup = neighbor_spline.lookup_evaluated_factor( + j * resample_factor); + const float index_factor = lookup.evaluated_index + lookup.factor; + float3 p; + neighbor_spline.sample_with_index_factors<float3>( + neighbor_spline.positions(), {&index_factor, 1}, {&p, 1}); + const float3 relative_coord = p - neighbor_root_cu; + float3 rotated_relative_coord = relative_coord; + mul_m3_v3(normal_rotation_cu, rotated_relative_coord); + positions_cu[first_point_i + j] += neighbor.weight * rotated_relative_coord; + } + } + } + }); + } +}; + +void AddOperation::on_stroke_extended(bContext *C, const StrokeExtension &stroke_extension) +{ + AddOperationExecutor executor; + executor.execute(*this, C, stroke_extension); +} + +std::unique_ptr<CurvesSculptStrokeOperation> new_add_operation() +{ + return std::make_unique<AddOperation>(); +} + +} // namespace blender::ed::sculpt_paint |