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Diffstat (limited to 'source/blender/blenkernel/intern/spline_bezier.cc')
| -rw-r--r-- | source/blender/blenkernel/intern/spline_bezier.cc | 576 |
1 files changed, 576 insertions, 0 deletions
diff --git a/source/blender/blenkernel/intern/spline_bezier.cc b/source/blender/blenkernel/intern/spline_bezier.cc new file mode 100644 index 00000000000..58a8f46730a --- /dev/null +++ b/source/blender/blenkernel/intern/spline_bezier.cc @@ -0,0 +1,576 @@ +/* + * This program is free software; you can redistribute it and/or + * modify it under the terms of the GNU General Public License + * as published by the Free Software Foundation; either version 2 + * of the License, or (at your option) any later version. + * + * This program is distributed in the hope that it will be useful, + * but WITHOUT ANY WARRANTY; without even the implied warranty of + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the + * GNU General Public License for more details. + * + * You should have received a copy of the GNU General Public License + * along with this program; if not, write to the Free Software Foundation, + * Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA. + */ + +#include "BLI_array.hh" +#include "BLI_span.hh" +#include "BLI_task.hh" + +#include "BKE_spline.hh" + +using blender::Array; +using blender::float3; +using blender::IndexRange; +using blender::MutableSpan; +using blender::Span; + +SplinePtr BezierSpline::copy() const +{ + return std::make_unique<BezierSpline>(*this); +} + +int BezierSpline::size() const +{ + const int size = positions_.size(); + BLI_assert(size == handle_types_left_.size()); + BLI_assert(size == handle_positions_left_.size()); + BLI_assert(size == handle_types_right_.size()); + BLI_assert(size == handle_positions_right_.size()); + BLI_assert(size == radii_.size()); + BLI_assert(size == tilts_.size()); + return size; +} + +int BezierSpline::resolution() const +{ + return resolution_; +} + +void BezierSpline::set_resolution(const int value) +{ + BLI_assert(value > 0); + resolution_ = value; + this->mark_cache_invalid(); +} + +void BezierSpline::add_point(const float3 position, + const HandleType handle_type_start, + const float3 handle_position_start, + const HandleType handle_type_end, + const float3 handle_position_end, + const float radius, + const float tilt) +{ + handle_types_left_.append(handle_type_start); + handle_positions_left_.append(handle_position_start); + positions_.append(position); + handle_types_right_.append(handle_type_end); + handle_positions_right_.append(handle_position_end); + radii_.append(radius); + tilts_.append(tilt); + this->mark_cache_invalid(); +} + +void BezierSpline::resize(const int size) +{ + handle_types_left_.resize(size); + handle_positions_left_.resize(size); + positions_.resize(size); + handle_types_right_.resize(size); + handle_positions_right_.resize(size); + radii_.resize(size); + tilts_.resize(size); + this->mark_cache_invalid(); +} + +MutableSpan<float3> BezierSpline::positions() +{ + return positions_; +} +Span<float3> BezierSpline::positions() const +{ + return positions_; +} +MutableSpan<float> BezierSpline::radii() +{ + return radii_; +} +Span<float> BezierSpline::radii() const +{ + return radii_; +} +MutableSpan<float> BezierSpline::tilts() +{ + return tilts_; +} +Span<float> BezierSpline::tilts() const +{ + return tilts_; +} +Span<BezierSpline::HandleType> BezierSpline::handle_types_left() const +{ + return handle_types_left_; +} +MutableSpan<BezierSpline::HandleType> BezierSpline::handle_types_left() +{ + return handle_types_left_; +} +Span<float3> BezierSpline::handle_positions_left() const +{ + this->ensure_auto_handles(); + return handle_positions_left_; +} +MutableSpan<float3> BezierSpline::handle_positions_left() +{ + this->ensure_auto_handles(); + return handle_positions_left_; +} +Span<BezierSpline::HandleType> BezierSpline::handle_types_right() const +{ + return handle_types_right_; +} +MutableSpan<BezierSpline::HandleType> BezierSpline::handle_types_right() +{ + return handle_types_right_; +} +Span<float3> BezierSpline::handle_positions_right() const +{ + this->ensure_auto_handles(); + return handle_positions_right_; +} +MutableSpan<float3> BezierSpline::handle_positions_right() +{ + this->ensure_auto_handles(); + return handle_positions_right_; +} + +static float3 previous_position(Span<float3> positions, const bool cyclic, const int i) +{ + if (i == 0) { + if (cyclic) { + return positions[positions.size() - 1]; + } + return 2.0f * positions[i] - positions[i + 1]; + } + return positions[i - 1]; +} + +static float3 next_position(Span<float3> positions, const bool cyclic, const int i) +{ + if (i == positions.size() - 1) { + if (cyclic) { + return positions[0]; + } + return 2.0f * positions[i] - positions[i - 1]; + } + return positions[i + 1]; +} + +/** + * Recalculate all #Auto and #Vector handles with positions automatically + * derived from the neighboring control points. + */ +void BezierSpline::ensure_auto_handles() const +{ + if (!auto_handles_dirty_) { + return; + } + + std::lock_guard lock{auto_handle_mutex_}; + if (!auto_handles_dirty_) { + return; + } + + for (const int i : IndexRange(this->size())) { + if (ELEM(HandleType::Auto, handle_types_left_[i], handle_types_right_[i])) { + const float3 prev_diff = positions_[i] - previous_position(positions_, is_cyclic_, i); + const float3 next_diff = next_position(positions_, is_cyclic_, i) - positions_[i]; + float prev_len = prev_diff.length(); + float next_len = next_diff.length(); + if (prev_len == 0.0f) { + prev_len = 1.0f; + } + if (next_len == 0.0f) { + next_len = 1.0f; + } + const float3 dir = next_diff / next_len + prev_diff / prev_len; + + /* This magic number is unfortunate, but comes from elsewhere in Blender. */ + const float len = dir.length() * 2.5614f; + if (len != 0.0f) { + if (handle_types_left_[i] == HandleType::Auto) { + const float prev_len_clamped = std::min(prev_len, next_len * 5.0f); + handle_positions_left_[i] = positions_[i] + dir * -(prev_len_clamped / len); + } + if (handle_types_right_[i] == HandleType::Auto) { + const float next_len_clamped = std::min(next_len, prev_len * 5.0f); + handle_positions_right_[i] = positions_[i] + dir * (next_len_clamped / len); + } + } + } + + if (handle_types_left_[i] == HandleType::Vector) { + const float3 prev = previous_position(positions_, is_cyclic_, i); + handle_positions_left_[i] = float3::interpolate(positions_[i], prev, 1.0f / 3.0f); + } + + if (handle_types_right_[i] == HandleType::Vector) { + const float3 next = next_position(positions_, is_cyclic_, i); + handle_positions_right_[i] = float3::interpolate(positions_[i], next, 1.0f / 3.0f); + } + } + + auto_handles_dirty_ = false; +} + +void BezierSpline::translate(const blender::float3 &translation) +{ + for (float3 &position : this->positions()) { + position += translation; + } + for (float3 &handle_position : this->handle_positions_left()) { + handle_position += translation; + } + for (float3 &handle_position : this->handle_positions_right()) { + handle_position += translation; + } + this->mark_cache_invalid(); +} + +void BezierSpline::transform(const blender::float4x4 &matrix) +{ + for (float3 &position : this->positions()) { + position = matrix * position; + } + for (float3 &handle_position : this->handle_positions_left()) { + handle_position = matrix * handle_position; + } + for (float3 &handle_position : this->handle_positions_right()) { + handle_position = matrix * handle_position; + } + this->mark_cache_invalid(); +} + +bool BezierSpline::point_is_sharp(const int index) const +{ + return ELEM(handle_types_left_[index], HandleType::Vector, HandleType::Free) || + ELEM(handle_types_right_[index], HandleType::Vector, HandleType::Free); +} + +bool BezierSpline::segment_is_vector(const int index) const +{ + if (index == this->size() - 1) { + if (is_cyclic_) { + return handle_types_right_.last() == HandleType::Vector && + handle_types_left_.first() == HandleType::Vector; + } + /* There is actually no segment in this case, but it's nice to avoid + * having a special case for the last segment in calling code. */ + return true; + } + return handle_types_right_[index] == HandleType::Vector && + handle_types_left_[index + 1] == HandleType::Vector; +} + +void BezierSpline::mark_cache_invalid() +{ + offset_cache_dirty_ = true; + position_cache_dirty_ = true; + mapping_cache_dirty_ = true; + tangent_cache_dirty_ = true; + normal_cache_dirty_ = true; + length_cache_dirty_ = true; + auto_handles_dirty_ = true; +} + +int BezierSpline::evaluated_points_size() const +{ + BLI_assert(this->size() > 0); + return this->control_point_offsets().last(); +} + +/** + * If the spline is not cyclic, the direction for the first and last points is just the + * direction formed by the corresponding handles and control points. In the unlikely situation + * that the handles define a zero direction, fallback to using the direction defined by the + * first and last evaluated segments already calculated in #Spline::evaluated_tangents(). + */ +void BezierSpline::correct_end_tangents() const +{ + if (is_cyclic_) { + return; + } + + MutableSpan<float3> tangents(evaluated_tangents_cache_); + + if (handle_positions_left_.first() != positions_.first()) { + tangents.first() = (positions_.first() - handle_positions_left_.first()).normalized(); + } + if (handle_positions_right_.last() != positions_.last()) { + tangents.last() = (handle_positions_right_.last() - positions_.last()).normalized(); + } +} + +static void bezier_forward_difference_3d(const float3 &point_0, + const float3 &point_1, + const float3 &point_2, + const float3 &point_3, + MutableSpan<float3> result) +{ + BLI_assert(result.size() > 0); + const float inv_len = 1.0f / static_cast<float>(result.size()); + const float inv_len_squared = inv_len * inv_len; + const float inv_len_cubed = inv_len_squared * inv_len; + + const float3 rt1 = 3.0f * (point_1 - point_0) * inv_len; + const float3 rt2 = 3.0f * (point_0 - 2.0f * point_1 + point_2) * inv_len_squared; + const float3 rt3 = (point_3 - point_0 + 3.0f * (point_1 - point_2)) * inv_len_cubed; + + float3 q0 = point_0; + float3 q1 = rt1 + rt2 + rt3; + float3 q2 = 2.0f * rt2 + 6.0f * rt3; + float3 q3 = 6.0f * rt3; + for (const int i : result.index_range()) { + result[i] = q0; + q0 += q1; + q1 += q2; + q2 += q3; + } +} + +void BezierSpline::evaluate_bezier_segment(const int index, + const int next_index, + MutableSpan<float3> positions) const +{ + if (this->segment_is_vector(index)) { + BLI_assert(positions.size() == 1); + positions.first() = positions_[index]; + } + else { + bezier_forward_difference_3d(positions_[index], + handle_positions_right_[index], + handle_positions_left_[next_index], + positions_[next_index], + positions); + } +} + +/** + * Returns access to a cache of offsets into the evaluated point array for each control point. + * While most control point edges generate the number of edges specified by the resolution, vector + * segments only generate one edge. + * + * \note The length of the result is one greater than the number of points, so that the last item + * is the total number of evaluated points. This is useful to avoid recalculating the size of the + * last segment everywhere. + */ +Span<int> BezierSpline::control_point_offsets() const +{ + if (!offset_cache_dirty_) { + return offset_cache_; + } + + std::lock_guard lock{offset_cache_mutex_}; + if (!offset_cache_dirty_) { + return offset_cache_; + } + + const int points_len = this->size(); + offset_cache_.resize(points_len + 1); + + MutableSpan<int> offsets = offset_cache_; + + int offset = 0; + for (const int i : IndexRange(points_len)) { + offsets[i] = offset; + offset += this->segment_is_vector(i) ? 1 : resolution_; + } + offsets.last() = offset; + + offset_cache_dirty_ = false; + return offsets; +} + +static void calculate_mappings_linear_resolution(Span<int> offsets, + const int size, + const int resolution, + const bool is_cyclic, + MutableSpan<float> r_mappings) +{ + const float first_segment_len_inv = 1.0f / offsets[1]; + for (const int i : IndexRange(0, offsets[1])) { + r_mappings[i] = i * first_segment_len_inv; + } + + const int grain_size = std::max(2048 / resolution, 1); + parallel_for(IndexRange(1, size - 2), grain_size, [&](IndexRange range) { + for (const int i_control_point : range) { + const int segment_len = offsets[i_control_point + 1] - offsets[i_control_point]; + const float segment_len_inv = 1.0f / segment_len; + for (const int i : IndexRange(segment_len)) { + r_mappings[offsets[i_control_point] + i] = i_control_point + i * segment_len_inv; + } + } + }); + + if (is_cyclic) { + const int last_segment_len = offsets[size] - offsets[size - 1]; + const float last_segment_len_inv = 1.0f / last_segment_len; + for (const int i : IndexRange(last_segment_len)) { + r_mappings[offsets[size - 1] + i] = size - 1 + i * last_segment_len_inv; + } + } + else { + r_mappings.last() = size - 1; + } +} + +/** + * Returns non-owning access to an array of values containing the information necessary to + * interpolate values from the original control points to evaluated points. The control point + * index is the integer part of each value, and the factor used for interpolating to the next + * control point is the remaining factional part. + */ +Span<float> BezierSpline::evaluated_mappings() const +{ + if (!mapping_cache_dirty_) { + return evaluated_mapping_cache_; + } + + std::lock_guard lock{mapping_cache_mutex_}; + if (!mapping_cache_dirty_) { + return evaluated_mapping_cache_; + } + + const int size = this->size(); + const int eval_size = this->evaluated_points_size(); + evaluated_mapping_cache_.resize(eval_size); + MutableSpan<float> mappings = evaluated_mapping_cache_; + + if (eval_size == 1) { + mappings.first() = 0.0f; + mapping_cache_dirty_ = false; + return mappings; + } + + Span<int> offsets = this->control_point_offsets(); + + calculate_mappings_linear_resolution(offsets, size, resolution_, is_cyclic_, mappings); + + mapping_cache_dirty_ = false; + return mappings; +} + +Span<float3> BezierSpline::evaluated_positions() const +{ + if (!position_cache_dirty_) { + return evaluated_position_cache_; + } + + std::lock_guard lock{position_cache_mutex_}; + if (!position_cache_dirty_) { + return evaluated_position_cache_; + } + + this->ensure_auto_handles(); + + const int size = this->size(); + const int eval_size = this->evaluated_points_size(); + evaluated_position_cache_.resize(eval_size); + + MutableSpan<float3> positions = evaluated_position_cache_; + + Span<int> offsets = this->control_point_offsets(); + + const int grain_size = std::max(512 / resolution_, 1); + parallel_for(IndexRange(size - 1), grain_size, [&](IndexRange range) { + for (const int i : range) { + this->evaluate_bezier_segment( + i, i + 1, positions.slice(offsets[i], offsets[i + 1] - offsets[i])); + } + }); + if (is_cyclic_) { + this->evaluate_bezier_segment( + size - 1, 0, positions.slice(offsets[size - 1], offsets[size] - offsets[size - 1])); + } + else { + /* Since evaluating the bezier segment doesn't add the final point, + * it must be added manually in the non-cyclic case. */ + positions.last() = positions_.last(); + } + + position_cache_dirty_ = false; + return positions; +} + +/** + * Convert the data encoded in #evaulated_mappings into its parts-- the information necessary + * to interpolate data from control points to evaluated points between them. The next control + * point index result will not overflow the size of the control point vectors. + */ +BezierSpline::InterpolationData BezierSpline::interpolation_data_from_index_factor( + const float index_factor) const +{ + const int points_len = this->size(); + + if (is_cyclic_) { + if (index_factor < points_len) { + const int index = std::floor(index_factor); + const int next_index = (index < points_len - 1) ? index + 1 : 0; + return InterpolationData{index, next_index, index_factor - index}; + } + return InterpolationData{points_len - 1, 0, 1.0f}; + } + + if (index_factor < points_len - 1) { + const int index = std::floor(index_factor); + const int next_index = index + 1; + return InterpolationData{index, next_index, index_factor - index}; + } + return InterpolationData{points_len - 2, points_len - 1, 1.0f}; +} + +/* Use a spline argument to avoid adding this to the header. */ +template<typename T> +static void interpolate_to_evaluated_points_impl(const BezierSpline &spline, + const blender::VArray<T> &source_data, + MutableSpan<T> result_data) +{ + Span<float> mappings = spline.evaluated_mappings(); + + for (const int i : result_data.index_range()) { + BezierSpline::InterpolationData interp = spline.interpolation_data_from_index_factor( + mappings[i]); + + const T &value = source_data[interp.control_point_index]; + const T &next_value = source_data[interp.next_control_point_index]; + + result_data[i] = blender::attribute_math::mix2(interp.factor, value, next_value); + } +} + +blender::fn::GVArrayPtr BezierSpline::interpolate_to_evaluated_points( + const blender::fn::GVArray &source_data) const +{ + BLI_assert(source_data.size() == this->size()); + + const int eval_size = this->evaluated_points_size(); + if (eval_size == 1) { + return source_data.shallow_copy(); + } + + blender::fn::GVArrayPtr new_varray; + blender::attribute_math::convert_to_static_type(source_data.type(), [&](auto dummy) { + using T = decltype(dummy); + if constexpr (!std::is_void_v<blender::attribute_math::DefaultMixer<T>>) { + Array<T> values(eval_size); + interpolate_to_evaluated_points_impl<T>(*this, source_data.typed<T>(), values); + new_varray = std::make_unique<blender::fn::GVArray_For_ArrayContainer<Array<T>>>( + std::move(values)); + } + }); + + return new_varray; +} |