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d95794ec8a
As many open source projects have started doing it, we're removing the current year from the copyright notice, so that we don't need to bump it every year. It seems like only the first year of publication is technically relevant for copyright notices, and even that seems to be something that many companies stopped listing altogether (in a version controlled codebase, the commits are a much better source of date of publication than a hardcoded copyright statement). We also now list Godot Engine contributors first as we're collectively the current maintainers of the project, and we clarify that the "exclusive" copyright of the co-founders covers the timespan before opensourcing (their further contributions are included as part of Godot Engine contributors). Also fixed "cf." Frenchism - it's meant as "refer to / see".
403 lines
14 KiB
C++
403 lines
14 KiB
C++
/**************************************************************************/
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/* delaunay_3d.h */
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/**************************************************************************/
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/* This file is part of: */
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/* GODOT ENGINE */
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/* https://godotengine.org */
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/**************************************************************************/
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/* Copyright (c) 2014-present Godot Engine contributors (see AUTHORS.md). */
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/* Copyright (c) 2007-2014 Juan Linietsky, Ariel Manzur. */
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/* */
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/* Permission is hereby granted, free of charge, to any person obtaining */
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/* a copy of this software and associated documentation files (the */
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/* "Software"), to deal in the Software without restriction, including */
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/* without limitation the rights to use, copy, modify, merge, publish, */
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/* distribute, sublicense, and/or sell copies of the Software, and to */
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/* permit persons to whom the Software is furnished to do so, subject to */
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/* the following conditions: */
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/* */
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/* The above copyright notice and this permission notice shall be */
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/* included in all copies or substantial portions of the Software. */
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/* */
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/* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, */
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/* EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF */
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/* MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. */
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/* IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY */
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/* CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, */
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/* TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE */
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/* SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE. */
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/**************************************************************************/
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#ifndef DELAUNAY_3D_H
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#define DELAUNAY_3D_H
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#include "core/io/file_access.h"
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#include "core/math/aabb.h"
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#include "core/math/projection.h"
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#include "core/math/vector3.h"
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#include "core/templates/local_vector.h"
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#include "core/templates/oa_hash_map.h"
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#include "core/templates/vector.h"
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#include "core/variant/variant.h"
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#include "thirdparty/misc/r128.h"
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class Delaunay3D {
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struct Simplex;
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enum {
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ACCEL_GRID_SIZE = 16
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};
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struct GridPos {
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Vector3i pos;
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List<Simplex *>::Element *E = nullptr;
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};
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struct Simplex {
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uint32_t points[4];
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R128 circum_center_x;
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R128 circum_center_y;
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R128 circum_center_z;
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R128 circum_r2;
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LocalVector<GridPos> grid_positions;
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List<Simplex *>::Element *SE = nullptr;
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_FORCE_INLINE_ Simplex() {}
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_FORCE_INLINE_ Simplex(uint32_t p_a, uint32_t p_b, uint32_t p_c, uint32_t p_d) {
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points[0] = p_a;
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points[1] = p_b;
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points[2] = p_c;
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points[3] = p_d;
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}
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};
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struct Triangle {
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uint32_t triangle[3];
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bool bad = false;
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_FORCE_INLINE_ bool operator==(const Triangle &p_triangle) const {
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return triangle[0] == p_triangle.triangle[0] && triangle[1] == p_triangle.triangle[1] && triangle[2] == p_triangle.triangle[2];
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}
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_FORCE_INLINE_ Triangle() {}
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_FORCE_INLINE_ Triangle(uint32_t p_a, uint32_t p_b, uint32_t p_c) {
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if (p_a > p_b) {
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SWAP(p_a, p_b);
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}
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if (p_b > p_c) {
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SWAP(p_b, p_c);
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}
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if (p_a > p_b) {
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SWAP(p_a, p_b);
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}
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triangle[0] = p_a;
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triangle[1] = p_b;
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triangle[2] = p_c;
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}
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};
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struct TriangleHasher {
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_FORCE_INLINE_ static uint32_t hash(const Triangle &p_triangle) {
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uint32_t h = hash_djb2_one_32(p_triangle.triangle[0]);
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h = hash_djb2_one_32(p_triangle.triangle[1], h);
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return hash_fmix32(hash_djb2_one_32(p_triangle.triangle[2], h));
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}
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};
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_FORCE_INLINE_ static void circum_sphere_compute(const Vector3 *p_points, Simplex *p_simplex) {
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// the only part in the algorithm where there may be precision errors is this one, so ensure that
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// we do it as maximum precision as possible
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R128 v0_x = p_points[p_simplex->points[0]].x;
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R128 v0_y = p_points[p_simplex->points[0]].y;
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R128 v0_z = p_points[p_simplex->points[0]].z;
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R128 v1_x = p_points[p_simplex->points[1]].x;
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R128 v1_y = p_points[p_simplex->points[1]].y;
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R128 v1_z = p_points[p_simplex->points[1]].z;
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R128 v2_x = p_points[p_simplex->points[2]].x;
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R128 v2_y = p_points[p_simplex->points[2]].y;
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R128 v2_z = p_points[p_simplex->points[2]].z;
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R128 v3_x = p_points[p_simplex->points[3]].x;
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R128 v3_y = p_points[p_simplex->points[3]].y;
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R128 v3_z = p_points[p_simplex->points[3]].z;
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//Create the rows of our "unrolled" 3x3 matrix
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R128 row1_x = v1_x - v0_x;
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R128 row1_y = v1_y - v0_y;
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R128 row1_z = v1_z - v0_z;
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R128 row2_x = v2_x - v0_x;
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R128 row2_y = v2_y - v0_y;
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R128 row2_z = v2_z - v0_z;
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R128 row3_x = v3_x - v0_x;
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R128 row3_y = v3_y - v0_y;
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R128 row3_z = v3_z - v0_z;
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R128 sq_lenght1 = row1_x * row1_x + row1_y * row1_y + row1_z * row1_z;
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R128 sq_lenght2 = row2_x * row2_x + row2_y * row2_y + row2_z * row2_z;
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R128 sq_lenght3 = row3_x * row3_x + row3_y * row3_y + row3_z * row3_z;
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//Compute the determinant of said matrix
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R128 determinant = row1_x * (row2_y * row3_z - row3_y * row2_z) - row2_x * (row1_y * row3_z - row3_y * row1_z) + row3_x * (row1_y * row2_z - row2_y * row1_z);
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// Compute the volume of the tetrahedron, and precompute a scalar quantity for re-use in the formula
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R128 volume = determinant / R128(6.f);
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R128 i12volume = R128(1.f) / (volume * R128(12.f));
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R128 center_x = v0_x + i12volume * ((row2_y * row3_z - row3_y * row2_z) * sq_lenght1 - (row1_y * row3_z - row3_y * row1_z) * sq_lenght2 + (row1_y * row2_z - row2_y * row1_z) * sq_lenght3);
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R128 center_y = v0_y + i12volume * (-(row2_x * row3_z - row3_x * row2_z) * sq_lenght1 + (row1_x * row3_z - row3_x * row1_z) * sq_lenght2 - (row1_x * row2_z - row2_x * row1_z) * sq_lenght3);
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R128 center_z = v0_z + i12volume * ((row2_x * row3_y - row3_x * row2_y) * sq_lenght1 - (row1_x * row3_y - row3_x * row1_y) * sq_lenght2 + (row1_x * row2_y - row2_x * row1_y) * sq_lenght3);
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//Once we know the center, the radius is clearly the distance to any vertex
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R128 rel1_x = center_x - v0_x;
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R128 rel1_y = center_y - v0_y;
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R128 rel1_z = center_z - v0_z;
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R128 radius1 = rel1_x * rel1_x + rel1_y * rel1_y + rel1_z * rel1_z;
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p_simplex->circum_center_x = center_x;
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p_simplex->circum_center_y = center_y;
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p_simplex->circum_center_z = center_z;
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p_simplex->circum_r2 = radius1;
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}
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_FORCE_INLINE_ static bool simplex_contains(const Vector3 *p_points, const Simplex &p_simplex, uint32_t p_vertex) {
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R128 v_x = p_points[p_vertex].x;
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R128 v_y = p_points[p_vertex].y;
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R128 v_z = p_points[p_vertex].z;
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R128 rel2_x = p_simplex.circum_center_x - v_x;
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R128 rel2_y = p_simplex.circum_center_y - v_y;
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R128 rel2_z = p_simplex.circum_center_z - v_z;
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R128 radius2 = rel2_x * rel2_x + rel2_y * rel2_y + rel2_z * rel2_z;
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return radius2 < (p_simplex.circum_r2 - R128(0.00001));
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}
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static bool simplex_is_coplanar(const Vector3 *p_points, const Simplex &p_simplex) {
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Plane p(p_points[p_simplex.points[0]], p_points[p_simplex.points[1]], p_points[p_simplex.points[2]]);
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if (ABS(p.distance_to(p_points[p_simplex.points[3]])) < CMP_EPSILON) {
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return true;
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}
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Projection cm;
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cm.columns[0][0] = p_points[p_simplex.points[0]].x;
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cm.columns[0][1] = p_points[p_simplex.points[1]].x;
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cm.columns[0][2] = p_points[p_simplex.points[2]].x;
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cm.columns[0][3] = p_points[p_simplex.points[3]].x;
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cm.columns[1][0] = p_points[p_simplex.points[0]].y;
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cm.columns[1][1] = p_points[p_simplex.points[1]].y;
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cm.columns[1][2] = p_points[p_simplex.points[2]].y;
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cm.columns[1][3] = p_points[p_simplex.points[3]].y;
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cm.columns[2][0] = p_points[p_simplex.points[0]].z;
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cm.columns[2][1] = p_points[p_simplex.points[1]].z;
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cm.columns[2][2] = p_points[p_simplex.points[2]].z;
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cm.columns[2][3] = p_points[p_simplex.points[3]].z;
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cm.columns[3][0] = 1.0;
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cm.columns[3][1] = 1.0;
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cm.columns[3][2] = 1.0;
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cm.columns[3][3] = 1.0;
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return ABS(cm.determinant()) <= CMP_EPSILON;
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}
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public:
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struct OutputSimplex {
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uint32_t points[4];
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};
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static Vector<OutputSimplex> tetrahedralize(const Vector<Vector3> &p_points) {
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uint32_t point_count = p_points.size();
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Vector3 *points = (Vector3 *)memalloc(sizeof(Vector3) * (point_count + 4));
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{
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const Vector3 *src_points = p_points.ptr();
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AABB rect;
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for (uint32_t i = 0; i < point_count; i++) {
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Vector3 point = src_points[i];
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if (i == 0) {
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rect.position = point;
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} else {
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rect.expand_to(point);
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}
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points[i] = point;
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}
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for (uint32_t i = 0; i < point_count; i++) {
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points[i] = (points[i] - rect.position) / rect.size;
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}
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float delta_max = Math::sqrt(2.0) * 20.0;
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Vector3 center = Vector3(0.5, 0.5, 0.5);
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// any simplex that contains everything is good
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points[point_count + 0] = center + Vector3(0, 1, 0) * delta_max;
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points[point_count + 1] = center + Vector3(0, -1, 1) * delta_max;
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points[point_count + 2] = center + Vector3(1, -1, -1) * delta_max;
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points[point_count + 3] = center + Vector3(-1, -1, -1) * delta_max;
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}
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List<Simplex *> acceleration_grid[ACCEL_GRID_SIZE][ACCEL_GRID_SIZE][ACCEL_GRID_SIZE];
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List<Simplex *> simplex_list;
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{
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//create root simplex
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Simplex *root = memnew(Simplex(point_count + 0, point_count + 1, point_count + 2, point_count + 3));
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root->SE = simplex_list.push_back(root);
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for (uint32_t i = 0; i < ACCEL_GRID_SIZE; i++) {
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for (uint32_t j = 0; j < ACCEL_GRID_SIZE; j++) {
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for (uint32_t k = 0; k < ACCEL_GRID_SIZE; k++) {
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GridPos gp;
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gp.E = acceleration_grid[i][j][k].push_back(root);
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gp.pos = Vector3i(i, j, k);
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root->grid_positions.push_back(gp);
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}
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}
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}
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circum_sphere_compute(points, root);
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}
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OAHashMap<Triangle, uint32_t, TriangleHasher> triangles_inserted;
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LocalVector<Triangle> triangles;
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for (uint32_t i = 0; i < point_count; i++) {
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bool unique = true;
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for (uint32_t j = i + 1; j < point_count; j++) {
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if (points[i].is_equal_approx(points[j])) {
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unique = false;
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break;
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}
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}
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if (!unique) {
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continue;
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}
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Vector3i grid_pos = Vector3i(points[i] * ACCEL_GRID_SIZE);
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grid_pos.x = CLAMP(grid_pos.x, 0, ACCEL_GRID_SIZE - 1);
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grid_pos.y = CLAMP(grid_pos.y, 0, ACCEL_GRID_SIZE - 1);
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grid_pos.z = CLAMP(grid_pos.z, 0, ACCEL_GRID_SIZE - 1);
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for (List<Simplex *>::Element *E = acceleration_grid[grid_pos.x][grid_pos.y][grid_pos.z].front(); E;) {
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List<Simplex *>::Element *N = E->next(); //may be deleted
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Simplex *simplex = E->get();
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if (simplex_contains(points, *simplex, i)) {
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static const uint32_t triangle_order[4][3] = {
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{ 0, 1, 2 },
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{ 0, 1, 3 },
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{ 0, 2, 3 },
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{ 1, 2, 3 },
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};
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for (uint32_t k = 0; k < 4; k++) {
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Triangle t = Triangle(simplex->points[triangle_order[k][0]], simplex->points[triangle_order[k][1]], simplex->points[triangle_order[k][2]]);
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uint32_t *p = triangles_inserted.lookup_ptr(t);
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if (p) {
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triangles[*p].bad = true;
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} else {
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triangles_inserted.insert(t, triangles.size());
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triangles.push_back(t);
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}
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}
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//remove simplex and continue
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simplex_list.erase(simplex->SE);
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for (uint32_t k = 0; k < simplex->grid_positions.size(); k++) {
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Vector3i p = simplex->grid_positions[k].pos;
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acceleration_grid[p.x][p.y][p.z].erase(simplex->grid_positions[k].E);
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}
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memdelete(simplex);
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}
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E = N;
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}
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for (uint32_t j = 0; j < triangles.size(); j++) {
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if (triangles[j].bad) {
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continue;
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}
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Simplex *new_simplex = memnew(Simplex(triangles[j].triangle[0], triangles[j].triangle[1], triangles[j].triangle[2], i));
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circum_sphere_compute(points, new_simplex);
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new_simplex->SE = simplex_list.push_back(new_simplex);
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{
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Vector3 center;
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center.x = double(new_simplex->circum_center_x);
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center.y = double(new_simplex->circum_center_y);
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center.z = double(new_simplex->circum_center_z);
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float radius2 = Math::sqrt(double(new_simplex->circum_r2));
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radius2 += 0.0001; //
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Vector3 extents = Vector3(radius2, radius2, radius2);
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Vector3i from = Vector3i((center - extents) * ACCEL_GRID_SIZE);
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Vector3i to = Vector3i((center + extents) * ACCEL_GRID_SIZE);
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from.x = CLAMP(from.x, 0, ACCEL_GRID_SIZE - 1);
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from.y = CLAMP(from.y, 0, ACCEL_GRID_SIZE - 1);
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from.z = CLAMP(from.z, 0, ACCEL_GRID_SIZE - 1);
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to.x = CLAMP(to.x, 0, ACCEL_GRID_SIZE - 1);
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to.y = CLAMP(to.y, 0, ACCEL_GRID_SIZE - 1);
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to.z = CLAMP(to.z, 0, ACCEL_GRID_SIZE - 1);
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for (int32_t x = from.x; x <= to.x; x++) {
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for (int32_t y = from.y; y <= to.y; y++) {
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for (int32_t z = from.z; z <= to.z; z++) {
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GridPos gp;
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gp.pos = Vector3(x, y, z);
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gp.E = acceleration_grid[x][y][z].push_back(new_simplex);
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new_simplex->grid_positions.push_back(gp);
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}
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}
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}
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}
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}
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triangles.clear();
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triangles_inserted.clear();
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}
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//print_line("end with simplices: " + itos(simplex_list.size()));
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Vector<OutputSimplex> ret_simplices;
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ret_simplices.resize(simplex_list.size());
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OutputSimplex *ret_simplicesw = ret_simplices.ptrw();
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uint32_t simplices_written = 0;
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for (Simplex *simplex : simplex_list) {
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bool invalid = false;
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for (int j = 0; j < 4; j++) {
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if (simplex->points[j] >= point_count) {
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invalid = true;
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break;
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}
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}
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if (invalid || simplex_is_coplanar(points, *simplex)) {
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memdelete(simplex);
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continue;
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}
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ret_simplicesw[simplices_written].points[0] = simplex->points[0];
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ret_simplicesw[simplices_written].points[1] = simplex->points[1];
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ret_simplicesw[simplices_written].points[2] = simplex->points[2];
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ret_simplicesw[simplices_written].points[3] = simplex->points[3];
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simplices_written++;
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memdelete(simplex);
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}
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ret_simplices.resize(simplices_written);
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memfree(points);
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return ret_simplices;
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}
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};
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#endif // DELAUNAY_3D_H
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