99 lines
3.4 KiB
C++
99 lines
3.4 KiB
C++
/* SPDX-License-Identifier: GPL-2.0-or-later */
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#pragma once
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/** \file
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* \ingroup bli
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*/
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#include "BLI_math_base.hh"
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#include "BLI_math_color.hh"
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#include "BLI_math_vector.hh"
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#include "BLI_vector.hh"
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namespace blender::length_parameterize {
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/**
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* Return the size of the necessary lengths array for a group of points, taking into account the
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* possible last cyclic segment.
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*
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* \note This is the same as #bke::curves::curve_segment_num.
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*/
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inline int lengths_num(const int points_num, const bool cyclic)
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{
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return cyclic ? points_num : points_num - 1;
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}
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/**
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* Accumulate the length of the next segment into each point.
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*/
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template<typename T>
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void accumulate_lengths(const Span<T> values, const bool cyclic, MutableSpan<float> lengths)
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{
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BLI_assert(lengths.size() == lengths_num(values.size(), cyclic));
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float length = 0.0f;
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for (const int i : IndexRange(values.size() - 1)) {
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length += math::distance(values[i], values[i + 1]);
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lengths[i] = length;
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}
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if (cyclic) {
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lengths.last() = length + math::distance(values.last(), values.first());
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}
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}
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template<typename T>
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void linear_interpolation(const Span<T> src,
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const Span<int> indices,
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const Span<float> factors,
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MutableSpan<T> dst)
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{
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BLI_assert(indices.size() == factors.size());
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BLI_assert(indices.size() == dst.size());
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const int last_src_index = src.index_range().last();
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int cyclic_sample_count = 0;
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for (int i = indices.index_range().last(); i > 0; i--) {
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if (indices[i] != last_src_index) {
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break;
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}
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dst[i] = math::interpolate(src.last(), src.first(), factors[i]);
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cyclic_sample_count++;
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}
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for (const int i : dst.index_range().drop_back(cyclic_sample_count)) {
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dst[i] = math::interpolate(src[indices[i]], src[indices[i] + 1], factors[i]);
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}
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}
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/**
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* Find the given number of points, evenly spaced along the provided length. For non-cyclic
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* sequences, the first point will always be included, and last point will always be included if
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* the #count is greater than zero. For cyclic sequences, the first point will always be included.
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*
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* \warning The #count argument must be greater than zero.
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*/
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void create_uniform_samples(Span<float> lengths,
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bool cyclic,
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MutableSpan<int> indices,
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MutableSpan<float> factors);
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/**
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* For each provided sample length, find the segment index and interpolation factor.
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*
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* \param lengths: The accumulated lengths of the original elements being sampled.
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* Could be calculated by #accumulate_lengths.
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* \param sample_lengths: Sampled locations in the #lengths array. Must be sorted and is expected
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* to be within the range of the #lengths values.
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* \param cyclic: Whether the points described by the #lenghts input is cyclic. This is likely
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* redundant information theoretically.
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* \param indices: The index of the previous point at each sample.
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* \param factors: The portion of the length in each segment at each sample.
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*/
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void create_samples_from_sorted_lengths(Span<float> lengths,
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Span<float> sample_lengths,
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bool cyclic,
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MutableSpan<int> indices,
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MutableSpan<float> factors);
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} // namespace blender::length_parameterize
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