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82 lines
2.2 KiB
C++
82 lines
2.2 KiB
C++
/*------------------------------------------------------------------------------
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* Copyright (c) 2023 by Bai Bing (seread@163.com)
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* See COPYING file for copying and redistribution conditions.
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*
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* Alians IT Studio.
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*----------------------------------------------------------------------------*/
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#pragma once
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#include "_Define.h"
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#include "utils/EssentiallyEqual.h"
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#include "ASPoint.h"
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namespace ais
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{
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template <typename PT = ais::Point>
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inline int cross(const PT &a, const PT &b, const PT &c)
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{
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return ais::dcmp((b.x - a.x) * (c.y - a.y) - (c.x - a.x) * (b.y - a.y));
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}
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template <typename PT = ais::Point>
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inline bool line_cross(const PT &p1, const PT &p2, const PT &q1, const PT &q2)
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{
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if (std::max(p1.x, p2.x) >= std::min(q1.x, q2.x) &&
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std::max(q1.x, q2.x) >= std::min(p1.x, p2.x) &&
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std::max(p1.y, p2.y) >= std::min(q1.y, q2.y) &&
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std::max(q1.y, q2.y) >= std::min(p1.y, p2.y))
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{
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if (cross(p1, p2, q1) * cross(p1, p2, q2) <= 0 && cross(q1, q2, p1) * cross(q1, q2, p2) <= 0)
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{
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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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template <typename PT = ais::Point>
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inline bool line_intersect(const std::vector<PT> &line, const std::vector<PT> &polygon)
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{
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for (auto &p : line)
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{
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if (p.in_polygon(polygon))
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return true;
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}
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size_t n = polygon.size();
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for (auto i = 0; i != n; i++)
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if (line_cross(line[0], line[1], polygon[i], polygon[((i + 1) % n)]))
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return true;
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return false;
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}
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template <typename PT = ais::Point>
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bool polygon_intersect(const std::vector<PT> &p1, const std::vector<PT> &p2)
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{
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for (auto &p : p1)
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{
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if (p.in_polygon(p2))
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return true;
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}
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for (auto &p : p2)
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{
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if (p.in_polygon(p1))
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return true;
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}
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size_t n = p1.size();
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size_t m = p2.size();
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for (auto i = 0; i != n; i++)
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for (auto j = 0; j != m; j++)
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if (line_cross(p1[i], p1[((i + 1) % n)], p2[j], p2[((j + 1) % m)]))
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return true;
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return false;
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}
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}
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