geometry/cross.hpp

• View this file on GitHub
• Last update: 2026-08-30 15:33:14+09:00
• Include: #include "geometry/cross.hpp"

Depends on

• geometry/base.hpp

Required by

• geometry/ccw.hpp
• geometry/convex-cut.hpp
• geometry/convex-hull.hpp
• geometry/cross-point.hpp
• geometry/distance-between-line-and-point.hpp
• geometry/distance-between-segment-and-point.hpp
• geometry/distance-between-segments.hpp
• 幾何ライブラリ (geometry/geometry.hpp)
• geometry/is-contained.hpp
• geometry/is-convex.hpp
• geometry/is-intersect.hpp
• geometry/is-parallel.hpp
• geometry/is-point-on-line.hpp
• geometry/polygon-area.hpp
• geometry/tangent-to-circle.hpp

Verified with

• test/mytest/geometry/geometry.test.cpp

Code

#pragma once

#include "base.hpp"

namespace geometry {
    // 外積(cross product) : a×b = |a||b|sinΘ
    inline D cross(const Point &a, const Point &b) {
        return (a.real() * b.imag() - a.imag() * b.real());
    }
} // namespace geometry

#line 2 "geometry/cross.hpp"

#line 2 "geometry/base.hpp"

#include <cmath>
#include <complex>

namespace geometry {
    // Point : 複素数型を位置ベクトルとして扱う
    // 実軸(real)をx軸、挙軸(imag)をy軸として見る
    using D = long double;
    using Point = std::complex<D>;
    const D EPS = 1e-7;
    const D PI = std::acos(D(-1));

    inline bool equal(const D &a, const D &b) { return std::fabs(a - b) < EPS; }
} // namespace geometry
#line 4 "geometry/cross.hpp"

namespace geometry {
    // 外積(cross product) : a×b = |a||b|sinΘ
    inline D cross(const Point &a, const Point &b) {
        return (a.real() * b.imag() - a.imag() * b.real());
    }
} // namespace geometry

Back to top page