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Differential D15348 Diff 53191 source/blender/blenlib/intern/length_parameterize.cc

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source/blender/blenlib/intern/length_parameterize.cc

/* SPDX-License-Identifier: GPL-2.0-or-later */ /* SPDX-License-Identifier: GPL-2.0-or-later */
#include "BLI_length_parameterize.hh" #include "BLI_length_parameterize.hh"
#include "BLI_task.hh"
namespace blender::length_parameterize { namespace blender::length_parameterize {
void create_uniform_samples(const Span<float> lengths, void sample_uniform(const Span<float> lengths,
const bool cyclic, const bool include_last_point,
MutableSpan<int> indices, MutableSpan<int> r_segment_indices,
MutableSpan<float> factors) MutableSpan<float> r_factors)
{ {
const int count = indices.size(); const int count = r_segment_indices.size();
BLI_assert(count > 0); BLI_assert(count > 0);
BLI_assert(lengths.size() >= 1); BLI_assert(lengths.size() >= 1);
BLI_assert(std::is_sorted(lengths.begin(), lengths.end())); BLI_assert(std::is_sorted(lengths.begin(), lengths.end()));
const int segments_num = lengths.size();
const int points_num = cyclic ? segments_num : segments_num + 1;
indices.first() = 0;
factors.first() = 0.0f;
if (count == 1) { if (count == 1) {
r_segment_indices[0] = 0;
r_factors[0] = 0.0f;
return; return;
} }
const float total_length = lengths.last(); const float total_length = lengths.last();
if (total_length == 0.0f) { const float step_length = total_length / (count - include_last_point);
indices.fill(0); threading::parallel_for(IndexRange(count), 512, [&](const IndexRange range) {
factors.fill(0.0f); SampleSegmentHint hint;
return; for (const int i : range) {
/* Use minimum to avoid issues with floating point accuracy. */
const float sample_length = std::min(total_length, i * step_length);
sample_at_length(lengths, sample_length, r_segment_indices[i], r_factors[i], &hint);
} }
});
const float step_length = total_length / (count - (cyclic ? 0 : 1));
const float step_length_inv = 1.0f / step_length;
int i_dst = 1;
/* Store the length at the previous point in a variable so it can start out at zero
* (the lengths array doesn't contain 0 for the first point). */
float prev_length = 0.0f;
for (const int i_src : IndexRange(points_num - 1)) {
const float next_length = lengths[i_src];
const float segment_length = next_length - prev_length;
if (segment_length == 0.0f) {
continue;
}
/* Add every sample that fits in this segment. */
const float segment_length_inv = 1.0f / segment_length;
const int segment_samples_num = std::ceil(next_length * step_length_inv - i_dst);
indices.slice(i_dst, segment_samples_num).fill(i_src);
for (const int i : IndexRange(i_dst, segment_samples_num)) {
const float length_in_segment = step_length * i - prev_length;
factors[i] = length_in_segment * segment_length_inv;
}
i_dst += segment_samples_num;
prev_length = next_length;
} }
/* Add the samples on the last cyclic segment if necessary, and also the samples void sample_at_lengths(const Span<float> accumulated_segment_lengths,
* that weren't created in the previous loop due to floating point inaccuracy. */
if (cyclic && lengths.size() > 1) {
indices.drop_front(i_dst).fill(points_num - 1);
const float segment_length = lengths.last() - lengths.last(1);
if (segment_length == 0.0f) {
return;
}
const float segment_length_inv = 1.0f / segment_length;
for (const int i : indices.index_range().drop_front(i_dst)) {
const float length_in_segment = step_length * i - prev_length;
factors[i] = length_in_segment * segment_length_inv;
}
}
else {
indices.drop_front(i_dst).fill(points_num - 2);
factors.drop_front(i_dst).fill(1.0f);
}
}
void create_samples_from_sorted_lengths(const Span<float> lengths,
const Span<float> sample_lengths, const Span<float> sample_lengths,
const bool cyclic, MutableSpan<int> r_segment_indices,
MutableSpan<int> indices, MutableSpan<float> r_factors)
MutableSpan<float> factors)
{ {
BLI_assert(std::is_sorted(lengths.begin(), lengths.end())); BLI_assert(
std::is_sorted(accumulated_segment_lengths.begin(), accumulated_segment_lengths.end()));
BLI_assert(std::is_sorted(sample_lengths.begin(), sample_lengths.end())); BLI_assert(std::is_sorted(sample_lengths.begin(), sample_lengths.end()));
BLI_assert(indices.size() == sample_lengths.size());
BLI_assert(indices.size() == factors.size());
const int segments_num = lengths.size();
const int points_num = cyclic ? segments_num : segments_num + 1;
const float total_length = lengths.last(); const int count = sample_lengths.size();
if (total_length == 0.0f) { BLI_assert(count == r_segment_indices.size());
indices.fill(0); BLI_assert(count == r_factors.size());
factors.fill(0.0f);
return; threading::parallel_for(IndexRange(count), 512, [&](const IndexRange range) {
} SampleSegmentHint hint;
for (const int i : range) {
int i_dst = 0; const float sample_length = sample_lengths[i];
/* Store the length at the previous point in a variable so it can start out at zero sample_at_length(
* (the lengths array doesn't contain 0 for the first point). */ accumulated_segment_lengths, sample_length, r_segment_indices[i], r_factors[i], &hint);
float prev_length = 0.0f;
for (const int i_src : IndexRange(points_num - 1)) {
const float next_length = lengths[i_src];
const float segment_length = next_length - prev_length;
if (segment_length == 0.0f) {
continue;
}
/* Add every sample that fits in this segment. It's also necessary to check if the last sample
* has been reached, since there is no upper bound on the number of samples in each segment. */
const float segment_length_inv = 1.0f / segment_length;
while (i_dst < sample_lengths.size() && sample_lengths[i_dst] < next_length) {
const float length_in_segment = sample_lengths[i_dst] - prev_length;
const float factor = length_in_segment * segment_length_inv;
indices[i_dst] = i_src;
factors[i_dst] = factor;
i_dst++;
}
prev_length = next_length;
}
/* Add the samples on the last cyclic segment if necessary, and also the samples
* that weren't created in the previous loop due to floating point inaccuracy. */
if (cyclic && lengths.size() > 1) {
const float segment_length = lengths.last() - lengths.last(1);
while (sample_lengths[i_dst] < total_length) {
const float length_in_segment = sample_lengths[i_dst] - prev_length;
const float factor = length_in_segment / segment_length;
indices[i_dst] = points_num - 1;
factors[i_dst] = factor;
i_dst++;
}
indices.drop_front(i_dst).fill(points_num - 1);
factors.drop_front(i_dst).fill(1.0f);
}
else {
indices.drop_front(i_dst).fill(points_num - 2);
factors.drop_front(i_dst).fill(1.0f);
} }
});
} }
} // namespace blender::length_parameterize } // namespace blender::length_parameterize