forked from bartvdbraak/blender
cba3498629
This brings new copyright header which supports GPL2 and 3. It wasn't really an issue before because we had agreement with Tobias, but now it's all documented in sources.
101 lines
2.7 KiB
C++
101 lines
2.7 KiB
C++
// Begin License:
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// Copyright (C) 2006-2014 Tobias Sargeant (tobias.sargeant@gmail.com).
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// All rights reserved.
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//
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// This file is part of the Carve CSG Library (http://carve-csg.com/)
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//
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// This file may be used under the terms of either the GNU General
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// Public License version 2 or 3 (at your option) as published by the
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// Free Software Foundation and appearing in the files LICENSE.GPL2
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// and LICENSE.GPL3 included in the packaging of this file.
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//
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// This file is provided "AS IS" with NO WARRANTY OF ANY KIND,
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// INCLUDING THE WARRANTIES OF DESIGN, MERCHANTABILITY AND FITNESS FOR
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// A PARTICULAR PURPOSE.
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// End:
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#if defined(HAVE_CONFIG_H)
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# include <carve_config.h>
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#endif
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#include <carve/csg.hpp>
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#include <carve/convex_hull.hpp>
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#include <algorithm>
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namespace {
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bool grahamScan(const std::vector<carve::geom2d::P2> &points,
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int vpp, int vp,
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const std::vector<int> &ordered,
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int start,
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std::vector<int> &result, int _i = 0) {
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carve::geom2d::P2 v1 = points[vp] - points[vpp];
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if (start == (int)ordered.size()) return true;
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for (int i = start; i < (int)ordered.size(); ++i) {
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int v = ordered[i];
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carve::geom2d::P2 v2 = points[v] - points[vp];
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double cp = v1.x * v2.y - v2.x * v1.y;
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if (cp < 0) return false;
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int j = i + 1;
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while (j < (int)ordered.size() && points[ordered[j]] == points[v]) j++;
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result.push_back(v);
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if (grahamScan(points, vp, v, ordered, j, result, _i + 1)) return true;
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result.pop_back();
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}
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return false;
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}
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}
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namespace carve {
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namespace geom {
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std::vector<int> convexHull(const std::vector<carve::geom2d::P2> &points) {
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double max_x = points[0].x;
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unsigned max_v = 0;
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for (unsigned i = 1; i < points.size(); ++i) {
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if (points[i].x > max_x) {
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max_x = points[i].x;
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max_v = i;
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}
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}
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std::vector<std::pair<double, double> > angle_dist;
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std::vector<int> ordered;
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angle_dist.reserve(points.size());
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ordered.reserve(points.size() - 1);
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for (unsigned i = 0; i < points.size(); ++i) {
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if (i == max_v) continue;
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angle_dist[i] = std::make_pair(carve::math::ANG(carve::geom2d::atan2(points[i] - points[max_v])), distance2(points[i], points[max_v]));
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ordered.push_back(i);
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}
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std::sort(ordered.begin(),
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ordered.end(),
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make_index_sort(angle_dist.begin()));
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std::vector<int> result;
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result.push_back(max_v);
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result.push_back(ordered[0]);
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if (!grahamScan(points, max_v, ordered[0], ordered, 1, result)) {
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result.clear();
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throw carve::exception("convex hull failed!");
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}
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return result;
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}
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}
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}
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