192 lines
5.0 KiB
C++
192 lines
5.0 KiB
C++
/* SPDX-FileCopyrightText: 2023 Blender Authors
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*
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* 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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* Generic algorithms for finding the largest and smallest elements in a span.
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*/
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#include <optional>
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#include "BLI_bounds_types.hh"
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#include "BLI_index_mask.hh"
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#include "BLI_math_vector.hh"
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#include "BLI_task.hh"
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namespace blender {
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namespace bounds {
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template<typename T> [[nodiscard]] inline Bounds<T> merge(const Bounds<T> &a, const Bounds<T> &b)
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{
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return {math::min(a.min, b.min), math::max(a.max, b.max)};
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}
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template<typename T>
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[[nodiscard]] inline std::optional<Bounds<T>> merge(const std::optional<Bounds<T>> &a,
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const std::optional<Bounds<T>> &b)
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{
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if (a.has_value() && b.has_value()) {
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return merge(*a, *b);
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}
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if (a.has_value()) {
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return a;
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}
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if (b.has_value()) {
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return b;
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}
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return std::nullopt;
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}
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/**
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* Find the smallest and largest values element-wise in the span.
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*/
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template<typename T> [[nodiscard]] inline std::optional<Bounds<T>> min_max(const Span<T> values)
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{
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if (values.is_empty()) {
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return std::nullopt;
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}
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const Bounds<T> init{values.first(), values.first()};
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return threading::parallel_reduce(
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values.index_range(),
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1024,
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init,
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[&](const IndexRange range, const Bounds<T> &init) {
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Bounds<T> result = init;
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for (const int i : range) {
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math::min_max(values[i], result.min, result.max);
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}
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return result;
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},
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[](const Bounds<T> &a, const Bounds<T> &b) { return merge(a, b); });
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}
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template<typename T>
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[[nodiscard]] inline std::optional<Bounds<T>> min_max(const IndexMask &mask, const Span<T> values)
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{
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if (values.is_empty() || mask.is_empty()) {
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return std::nullopt;
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}
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if (mask.size() == values.size()) {
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/* To avoid mask slice/lookup. */
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return min_max(values);
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}
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const Bounds<T> init{values.first(), values.first()};
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return threading::parallel_reduce(
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mask.index_range(),
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1024,
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init,
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[&](const IndexRange range, const Bounds<T> &init) {
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Bounds<T> result = init;
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mask.slice(range).foreach_index_optimized<int64_t>(
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[&](const int i) { math::min_max(values[i], result.min, result.max); });
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return result;
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},
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[](const Bounds<T> &a, const Bounds<T> &b) { return merge(a, b); });
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}
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/**
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* Find the smallest and largest values element-wise in the span, adding the radius to each element
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* first. The template type T is expected to have an addition operator implemented with RadiusT.
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*/
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template<typename T, typename RadiusT>
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[[nodiscard]] inline std::optional<Bounds<T>> min_max_with_radii(const Span<T> values,
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const Span<RadiusT> radii)
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{
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BLI_assert(values.size() == radii.size());
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if (values.is_empty()) {
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return std::nullopt;
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}
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const Bounds<T> init{values.first(), values.first()};
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return threading::parallel_reduce(
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values.index_range(),
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1024,
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init,
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[&](const IndexRange range, const Bounds<T> &init) {
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Bounds<T> result = init;
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for (const int i : range) {
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result.min = math::min(values[i] - radii[i], result.min);
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result.max = math::max(values[i] + radii[i], result.max);
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}
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return result;
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},
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[](const Bounds<T> &a, const Bounds<T> &b) { return merge(a, b); });
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}
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} // namespace bounds
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namespace detail {
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template<typename T, int Size>
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[[nodiscard]] inline bool less_or_equal_than(const VecBase<T, Size> &a, const VecBase<T, Size> &b)
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{
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for (int i = 0; i < Size; i++) {
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if (a[i] <= b[i]) {
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return true;
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}
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}
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return false;
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}
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} // namespace detail
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template<typename T> inline bool Bounds<T>::is_empty() const
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{
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if constexpr (std::is_integral<T>::value || std::is_floating_point<T>::value) {
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return this->max <= this->min;
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}
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else {
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return detail::less_or_equal_than(this->max, this->min);
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}
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}
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template<typename T> inline T Bounds<T>::center() const
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{
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return math::midpoint(this->min, this->max);
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}
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template<typename T> inline T Bounds<T>::size() const
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{
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return math::abs(max - min);
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}
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template<typename T> inline void Bounds<T>::translate(const T &offset)
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{
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this->min += offset;
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this->max += offset;
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}
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template<typename T> inline void Bounds<T>::scale_from_center(const T &scale)
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{
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const T center = this->center();
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const T new_half_size = this->size() / T(2) * scale;
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this->min = center - new_half_size;
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this->max = center + new_half_size;
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}
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template<typename T> inline void Bounds<T>::resize(const T &new_size)
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{
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this->min = this->center() - (new_size / T(2));
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this->max = this->min + new_size;
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}
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template<typename T> inline void Bounds<T>::recenter(const T &new_center)
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{
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const T offset = new_center - this->center();
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this->translate(offset);
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}
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template<typename T>
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template<typename PaddingT>
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inline void Bounds<T>::pad(const PaddingT &padding)
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{
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this->min = this->min - padding;
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this->max = this->max + padding;
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}
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} // namespace blender
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