121 lines
4.2 KiB
C++
121 lines
4.2 KiB
C++
/* SPDX-License-Identifier: GPL-2.0-or-later */
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/** \file
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* \ingroup bke
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*/
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#include "BKE_attribute_math.hh"
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#include "BKE_curves.hh"
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namespace blender::bke::curves::catmull_rom {
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int calculate_evaluated_size(const int points_num, const bool cyclic, const int resolution)
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{
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const int eval_size = resolution * curve_segment_size(points_num, cyclic);
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/* If the curve isn't cyclic, one last point is added to the final point. */
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return cyclic ? eval_size : eval_size + 1;
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}
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/* Adapted from Cycles #catmull_rom_basis_eval function. */
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template<typename T>
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static T calculate_basis(const T &a, const T &b, const T &c, const T &d, const float parameter)
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{
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const float t = parameter;
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const float s = 1.0f - parameter;
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const float n0 = -t * s * s;
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const float n1 = 2.0f + t * t * (3.0f * t - 5.0f);
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const float n2 = 2.0f + s * s * (3.0f * s - 5.0f);
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const float n3 = -s * t * t;
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return 0.5f * (a * n0 + b * n1 + c * n2 + d * n3);
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}
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template<typename T>
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static void evaluate_segment(const T &a, const T &b, const T &c, const T &d, MutableSpan<T> dst)
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{
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const float step = 1.0f / dst.size();
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dst.first() = b;
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for (const int i : dst.index_range().drop_front(1)) {
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dst[i] = calculate_basis<T>(a, b, c, d, i * step);
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}
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}
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template<typename T>
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static void interpolate_to_evaluated(const Span<T> src,
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const bool cyclic,
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const int resolution,
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MutableSpan<T> dst)
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{
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BLI_assert(dst.size() == calculate_evaluated_size(src.size(), cyclic, resolution));
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/* - First deal with one and two point curves need special attention.
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* - Then evaluate the first and last segment(s) whose control points need to wrap around
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* to the other side of the source array.
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* - Finally evaluate all of the segments in the middle in parallel. */
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if (src.size() == 1) {
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dst.first() = src.first();
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return;
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}
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if (src.size() == 2) {
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evaluate_segment(src.first(), src.first(), src.last(), src.last(), dst.take_front(resolution));
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if (cyclic) {
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evaluate_segment(
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src.last(), src.last(), src.first(), src.first(), dst.take_back(resolution));
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}
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else {
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dst.last() = src.last();
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}
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return;
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}
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if (cyclic) {
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/* The first segment. */
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evaluate_segment(src.last(), src[0], src[1], src[2], dst.take_front(resolution));
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/* The second-to-last segment. */
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evaluate_segment(src.last(2),
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src.last(1),
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src.last(),
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src.first(),
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dst.take_back(resolution * 2).drop_back(resolution));
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/* The last segment. */
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evaluate_segment(src.last(1), src.last(), src[0], src[1], dst.take_back(resolution));
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}
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else {
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/* The first segment. */
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evaluate_segment(src[0], src[0], src[1], src[2], dst.take_front(resolution));
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/* The last segment. */
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evaluate_segment(
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src.last(2), src.last(1), src.last(), src.last(), dst.drop_back(1).take_back(resolution));
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/* The final point of the last segment. */
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dst.last() = src.last();
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}
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/* Evaluate every segment that isn't the first or last. */
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const int grain_size = std::max(512 / resolution, 1);
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const IndexRange inner_range = src.index_range().drop_back(2).drop_front(1);
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threading::parallel_for(inner_range, grain_size, [&](IndexRange range) {
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for (const int i : range) {
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const IndexRange segment_range(resolution * i, resolution);
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evaluate_segment(src[i - 1], src[i], src[i + 1], src[i + 2], dst.slice(segment_range));
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}
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});
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}
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void interpolate_to_evaluated(const GSpan src,
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const bool cyclic,
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const int resolution,
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GMutableSpan dst)
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{
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attribute_math::convert_to_static_type(src.type(), [&](auto dummy) {
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using T = decltype(dummy);
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/* TODO: Use DefaultMixer or other generic mixing in the basis evaluation function to simplify
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* supporting more types. */
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if constexpr (is_same_any_v<T, float, float2, float3, float4, int8_t, int, int64_t>) {
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interpolate_to_evaluated(src.typed<T>(), cyclic, resolution, dst.typed<T>());
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}
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});
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}
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} // namespace blender::bke::curves::catmull_rom
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