Intersection between a line and a segment
(Mylib/Geometry/Float/intersect_line_segment.cpp)
Operations
Requirements
Notes
Problems
References
Depends on
Required by
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Code
#pragma once
#include <vector>
#include "Mylib/Geometry/Float/geometry_template.cpp"
namespace haar_lib {
namespace intersect_line_segment_impl {
enum class status_t { LEFTSIDE,
RIGHTSIDE,
OVERLAPPED,
CROSSED };
template <typename T>
struct result {
status_t status;
std::vector<point<T>> crosspoints;
bool is_leftside() const { return status == status_t::LEFTSIDE; }
bool is_rightside() const { return status == status_t::RIGHTSIDE; }
bool is_overlapped() const { return status == status_t::OVERLAPPED; }
bool is_crossed() const { return status == status_t::CROSSED; }
};
} // namespace intersect_line_segment_impl
template <typename T>
auto intersect_line_segment(const line<T> &l, const segment<T> &s) {
using namespace intersect_line_segment_impl;
const T a = cross(diff(l), s.from - l.from);
const T b = cross(diff(l), s.to - l.from);
if (a == 0 and b == 0) {
return result<T>({status_t::OVERLAPPED, {}});
} else if (a < 0 and b < 0) {
return result<T>({status_t::RIGHTSIDE, {}});
} else if (a > 0 and b > 0) {
return result<T>({status_t::LEFTSIDE, {}});
}
return result<T>(
{status_t::CROSSED,
{s.from + diff(s) * cross(diff(l), l.from - s.from) / cross(l, s)}});
}
} // namespace haar_lib
#line 2 "Mylib/Geometry/Float/intersect_line_segment.cpp"
#include <vector>
#line 2 "Mylib/Geometry/Float/geometry_template.cpp"
#include <cmath>
#include <iostream>
#line 5 "Mylib/Geometry/Float/geometry_template.cpp"
namespace haar_lib {
template <typename T>
struct vec {
T x, y;
vec() {}
vec(T x, T y) : x(x), y(y) {}
friend auto operator+(const vec &a, const vec &b) { return vec(a.x + b.x, a.y + b.y); }
friend auto operator-(const vec &a, const vec &b) { return vec(a.x - b.x, a.y - b.y); }
friend auto operator-(const vec &a) { return vec(-a.x, -a.y); }
friend bool operator==(const vec &a, const vec &b) { return a.x == b.x and a.y == b.y; }
friend bool operator!=(const vec &a, const vec &b) { return !(a == b); }
friend bool operator<(const vec &a, const vec &b) { return a.x < b.x or (a.x == b.x and a.y < b.y); }
friend std::istream &operator>>(std::istream &s, vec &a) {
s >> a.x >> a.y;
return s;
}
};
template <typename T, typename U>
auto operator*(const vec<T> &a, const U &k) { return vec<T>(a.x * k, a.y * k); }
template <typename T, typename U>
auto operator*(const U &k, const vec<T> &a) { return vec<T>(a.x * k, a.y * k); }
template <typename T, typename U>
auto operator/(const vec<T> &a, const U &k) { return vec<T>(a.x / k, a.y / k); }
template <typename T>
using point = vec<T>;
template <typename T>
T abs(const vec<T> &a) { return sqrt(a.x * a.x + a.y * a.y); }
template <typename T>
T abs_sq(const vec<T> &a) { return a.x * a.x + a.y * a.y; }
template <typename T>
T dot(const vec<T> &a, const vec<T> &b) { return a.x * b.x + a.y * b.y; }
template <typename T>
T cross(const vec<T> &a, const vec<T> &b) { return a.x * b.y - a.y * b.x; }
template <typename T>
auto unit(const vec<T> &a) { return a / abs(a); }
template <typename T>
auto normal(const vec<T> &p) { return vec<T>(-p.y, p.x); }
template <typename T>
auto polar(const T &r, const T &ang) { return vec<T>(r * cos(ang), r * sin(ang)); }
template <typename T>
T angle(const vec<T> &a, const vec<T> &b) { return atan2(b.y - a.y, b.x - a.x); }
template <typename T>
T phase(const vec<T> &a) { return atan2(a.y, a.x); }
template <typename T>
T angle_diff(const vec<T> &a, const vec<T> &b) {
T r = phase(b) - phase(a);
if (r < -M_PI)
return r + 2 * M_PI;
else if (r > M_PI)
return r - 2 * M_PI;
return r;
}
template <typename T>
struct line {
point<T> from, to;
line() : from(), to() {}
line(const point<T> &from, const point<T> &to) : from(from), to(to) {}
};
template <typename T>
using segment = line<T>;
template <typename T>
auto unit(const line<T> &a) { return unit(a.to - a.from); }
template <typename T>
auto normal(const line<T> &a) { return normal(a.to - a.from); }
template <typename T>
auto diff(const segment<T> &a) { return a.to - a.from; }
template <typename T>
T abs(const segment<T> &a) { return abs(diff(a)); }
template <typename T>
T dot(const line<T> &a, const line<T> &b) { return dot(diff(a), diff(b)); }
template <typename T>
T cross(const line<T> &a, const line<T> &b) { return cross(diff(a), diff(b)); }
template <typename T>
using polygon = std::vector<point<T>>;
template <typename T>
struct circle {
point<T> center;
T radius;
circle() : center(), radius(0) {}
circle(const point<T> ¢er, T radius) : center(center), radius(radius) {}
};
template <typename T>
std::ostream &operator<<(std::ostream &s, const vec<T> &a) {
s << "(" << a.x << ", " << a.y << ")";
return s;
}
template <typename T>
std::ostream &operator<<(std::ostream &s, const line<T> &a) {
s << "(" << a.from << " -> " << a.to << ")";
return s;
}
template <typename T>
std::ostream &operator<<(std::ostream &s, const circle<T> &a) {
s << "("
<< "center: " << a.center << ", "
<< "radius: " << a.radius << ")";
return s;
}
} // namespace haar_lib
#line 4 "Mylib/Geometry/Float/intersect_line_segment.cpp"
namespace haar_lib {
namespace intersect_line_segment_impl {
enum class status_t { LEFTSIDE,
RIGHTSIDE,
OVERLAPPED,
CROSSED };
template <typename T>
struct result {
status_t status;
std::vector<point<T>> crosspoints;
bool is_leftside() const { return status == status_t::LEFTSIDE; }
bool is_rightside() const { return status == status_t::RIGHTSIDE; }
bool is_overlapped() const { return status == status_t::OVERLAPPED; }
bool is_crossed() const { return status == status_t::CROSSED; }
};
} // namespace intersect_line_segment_impl
template <typename T>
auto intersect_line_segment(const line<T> &l, const segment<T> &s) {
using namespace intersect_line_segment_impl;
const T a = cross(diff(l), s.from - l.from);
const T b = cross(diff(l), s.to - l.from);
if (a == 0 and b == 0) {
return result<T>({status_t::OVERLAPPED, {}});
} else if (a < 0 and b < 0) {
return result<T>({status_t::RIGHTSIDE, {}});
} else if (a > 0 and b > 0) {
return result<T>({status_t::LEFTSIDE, {}});
}
return result<T>(
{status_t::CROSSED,
{s.from + diff(s) * cross(diff(l), l.from - s.from) / cross(l, s)}});
}
} // namespace haar_lib
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