Differential D14284 Diff 49351 source/blender/blenkernel/intern/curve_bezier.cc

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source/blender/blenkernel/intern/curve_bezier.cc

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				/* SPDX-License-Identifier: GPL-2.0-or-later */

				/** \file
				* \ingroup bke
				*/

				#include "BKE_attribute_math.hh"
				#include "BKE_curves.hh"

				namespace blender::bke::curves::bezier {

				bool segment_is_vector(const Span<int8_t> handle_types_left,
				const Span<int8_t> handle_types_right,
				const int segment_index)
				{
				BLI_assert(handle_types_left.index_range().drop_back(1).contains(segment_index));
				return handle_types_right[segment_index] == BEZIER_HANDLE_VECTOR &&
				handle_types_left[segment_index + 1] == BEZIER_HANDLE_VECTOR;
				}

				bool last_cylic_segment_is_vector(const Span<int8_t> handle_types_left,
				const Span<int8_t> handle_types_right)
				{
				return handle_types_right.last() == BEZIER_HANDLE_VECTOR &&
				handle_types_left.first() == BEZIER_HANDLE_VECTOR;
				}

				void calculate_evaluated_offsets(const Span<int8_t> handle_types_left,
				const Span<int8_t> handle_types_right,
				const bool cyclic,
				const int resolution,
				MutableSpan<int> evaluated_offsets)
				{
				const int size = handle_types_left.size();
				BLI_assert(evaluated_offsets.size() == size);

				if (size == 1) {
				evaluated_offsets.first() = 1;
				return;
				}

				int offset = 0;

				for (const int i : IndexRange(size - 1)) {
				offset += segment_is_vector(handle_types_left, handle_types_right, i) ? 1 : resolution;
				evaluated_offsets[i] = offset;
				}

				if (cyclic) {
				offset += last_cylic_segment_is_vector(handle_types_left, handle_types_right) ? 1 : resolution;
				evaluated_offsets.last(1) = offset;
				}
				else {
				offset++;
				}

				evaluated_offsets.last() = offset;
				}

				void evaluate_segment(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 calculate_evaluated_positions(const Span<float3> positions,
				const Span<float3> handles_left,
				const Span<float3> handles_right,
				const Span<int> evaluated_offsets,
				MutableSpan<float3> evaluated_positions)
				{
				BLI_assert(evaluated_offsets.last() == evaluated_positions.size());
				BLI_assert(evaluated_offsets.size() == positions.size());

				/* Evaluate the first segment. */
				evaluate_segment(positions.first(),
				handles_right.first(),
				handles_left[1],
				positions[1],
				evaluated_positions.take_front(evaluated_offsets.first()));

				/* Give each task fewer segments as the resolution gets larger. */
				const int grain_size = std::max(evaluated_positions.size() / positions.size() * 32, 1L);
				threading::parallel_for(
				positions.index_range().drop_back(1).drop_front(1), grain_size, [&](IndexRange range) {
				for (const int i : range) {
				const IndexRange evaluated_range = offsets_to_range(evaluated_offsets, i - 1);
				if (evaluated_range.size() == 1) {
				evaluated_positions[evaluated_range.first()] = positions[i];
				}
				else {
				evaluate_segment(positions[i],
				handles_right[i],
				handles_left[i + 1],
				positions[i + 1],
				evaluated_positions.slice(evaluated_range));
				}
				}
				});

				/* Evaluate the final cyclic segment if necessary. */
				const IndexRange evaluated_range = offsets_to_range(evaluated_offsets, positions.size() - 2);
				if (evaluated_range.size() == 1) {
				evaluated_positions.last() = positions.last();
				}
				else {
				evaluate_segment(positions.last(),
				handles_right.last(),
				handles_left.first(),
				positions.first(),
				evaluated_positions.slice(evaluated_range));
				}
				}

				/** \} */

				} // namespace blender::bke::curves::bezier