269 lines
6.5 KiB
C++
Executable File
269 lines
6.5 KiB
C++
Executable File
#ifndef LINE2D_H
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#define LINE2D_H
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//#include <KLib/geo/Line.h>
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#include "Point2.h"
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#include "Ray2.h"
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class Line2 {
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public:
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Point2 p1;
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Point2 p2;
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public:
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/** empty ctor */
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Line2() : p1(), p2() {;}
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/** value ctor */
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Line2(const Point2 p1, const Point2 p2) : p1(p1), p2(p2) {;}
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/** value ctor */
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Line2(const float x1, const float y1, const float x2, const float y2) : p1(x1,y1), p2(x2,y2) {;}
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Line2 operator * (const float v) const {return Line2(p1*v, p2*v);}
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// bool getSegmentIntersection(const Line& other) const {
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// static K::Point p;
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// return K::Line::getSegmentIntersection(other, p);
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// }
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float getAngle() const {
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return std::atan2(p2.y-p1.y, p2.x-p1.x);
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}
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void reverse() {
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std::swap(p1, p2);
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}
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float getLength() const {
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return p1.getDistance(p2);
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}
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/** get intersection between these two lines (unlimited length!) */
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bool getLineIntersection(const Line2& other, Point2& result) const {
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double bx = p2.x - p1.x;
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double by = p2.y - p1.y;
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double dx = other.p2.x - other.p1.x;
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double dy = other.p2.y - other.p1.y;
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double b_dot_d_perp = bx*dy - by*dx;
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if(b_dot_d_perp == 0) {return false;}
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double cx = other.p1.x - p1.x;
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double cy = other.p1.y - p1.y;
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double t = (cx*dy - cy*dx) / b_dot_d_perp;
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result.x = p1.x + t * bx;
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result.y = p1.y + t * by;
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return true;
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}
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bool getSegmentIntersection(const Line2& other) const {
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const float p0_x = p1.x, p1_x = p2.x, p2_x = other.p1.x, p3_x = other.p2.x;
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const float p0_y = p1.y, p1_y = p2.y, p2_y = other.p1.y, p3_y = other.p2.y;
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const float s1_x = p1_x - p0_x;
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const float s1_y = p1_y - p0_y;
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const float s2_x = p3_x - p2_x;
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const float s2_y = p3_y - p2_y;
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const float s = (-s1_y * (p0_x - p2_x) + s1_x * (p0_y - p2_y)) / (-s2_x * s1_y + s1_x * s2_y);
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const float t = ( s2_x * (p0_y - p2_y) - s2_y * (p0_x - p2_x)) / (-s2_x * s1_y + s1_x * s2_y);
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if (s >= 0 && s <= 1 && t >= 0 && t <= 1) {
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// Collision detected
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// if (i_x != NULL)
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// *i_x = p0_x + (t * s1_x);
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// if (i_y != NULL)
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// *i_y = p0_y + (t * s1_y);
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return true;
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}
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return false; // No collision
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// const double delta = 0.0000001;
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// const double bx = p2.x - p1.x;
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// const double by = p2.y - p1.y;
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// const double dx = other.p2.x - other.p1.x;
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// const double dy = other.p2.y - other.p1.y;
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// const double b_dot_d_perp = bx*dy - by*dx;
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// if (std::abs(b_dot_d_perp) == 0) {return false;}
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// const double cx = other.p1.x - p1.x;
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// const double cy = other.p1.y - p1.y;
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// const double t = (cx * dy - cy * dx) / b_dot_d_perp;
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// if(t < 0+delta || t > 1-delta) {
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// return false;}
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// const double u = (cx * by - cy * bx) / b_dot_d_perp;
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// if(u < 0+delta || u > 1-delta) {
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// return false;}
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// return true;
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}
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bool getSegmentIntersection(const Line2& other, Point2& result) const {
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const float delta = 0.000001;
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const float bx = p2.x - p1.x;
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const float by = p2.y - p1.y;
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const float dx = other.p2.x - other.p1.x;
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const float dy = other.p2.y - other.p1.y;
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const float b_dot_d_perp = bx*dy - by*dx;
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if(b_dot_d_perp == 0) {return false;}
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const float cx = other.p1.x - p1.x;
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const float cy = other.p1.y - p1.y;
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const float t = (cx * dy - cy * dx) / b_dot_d_perp;
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if(t < 0+delta || t > 1-delta) {
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return false;}
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const float u = (cx * by - cy * bx) / b_dot_d_perp;
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if(u < 0+delta || u > 1-delta) {
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return false;}
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result.x = p1.x + t * bx;
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result.y = p1.y + t * by;
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return true;
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}
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bool getSegmentIntersectionInt(const Line2& other, Point2& result) const {
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int mul = 100;
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const float p0_x = std::round(p1.x*mul), p1_x = std::round(p2.x*mul), p2_x = std::round(other.p1.x*mul), p3_x = std::round(other.p2.x*mul);
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const float p0_y = std::round(p1.y*mul), p1_y = std::round(p2.y*mul), p2_y = std::round(other.p1.y*mul), p3_y = std::round(other.p2.y*mul);
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const float s1_x = p1_x - p0_x;
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const float s1_y = p1_y - p0_y;
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const float s2_x = p3_x - p2_x;
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const float s2_y = p3_y - p2_y;
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const float s = (-s1_y * (p0_x - p2_x) + s1_x * (p0_y - p2_y)) / (-s2_x * s1_y + s1_x * s2_y);
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const float t = ( s2_x * (p0_y - p2_y) - s2_y * (p0_x - p2_x)) / (-s2_x * s1_y + s1_x * s2_y);
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if (s >= 0 && s <= 1 && t >= 0 && t <= 1) {
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result.x = (p0_x + (t * s1_x)) / mul;
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result.y = (p0_y + (t * s1_y)) / mul;
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return true;
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}
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return false;
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}
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/** does the line intersect with the given ray? */
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bool intersects(const Ray2& ray, Point2& result) const {
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//https://stackoverflow.com/questions/563198/how-do-you-detect-where-two-line-segments-intersect/565282#565282
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const float p0_x = p1.x, p1_x = p2.x;
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const float p0_y = p1.y, p1_y = p2.y;
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const float p2_x = ray.start.x;//, p3_x = other.p2.x;
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const float p2_y = ray.start.y;//, p3_y = other.p2.y;
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const float s1_x = p1_x - p0_x;
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const float s1_y = p1_y - p0_y;
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const float s2_x = ray.dir.x; // p3_x - p2_x;
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const float s2_y = ray.dir.y; // p3_y - p2_y;
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// ray_start + s * ray_dir
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const float s = (-s1_y * (p0_x - p2_x) + s1_x * (p0_y - p2_y)) / (-s2_x * s1_y + s1_x * s2_y);
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// before the ray's start?
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if (s < 0) {return false;}
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// line.p1 + t * (line.p2-line.p1)
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const float t = ( s2_x * (p0_y - p2_y) - s2_y * (p0_x - p2_x)) / (-s2_x * s1_y + s1_x * s2_y);
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// t must be between 0 and 1, otherwise we are before the line's start / after the line's end
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if (t < 0 || t > 1) {return false;}
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// intersection
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result.x = (p0_x + (t * s1_x));
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result.y = (p0_y + (t * s1_y));
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return true;
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}
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};
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static inline bool intersects(const Line2& l1, const Line2& l2, bool limit, Point2& pos) {
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// (sx1,sy1) + (dx1, dy1)*u = (sx2, sy2) + (dx2, dy2)*v
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// solve((c+d*v-a)/b = (g+h*v-e)/f, v)
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// solve((a+b*u-c)/d = (e+f*u-g)/h, u)
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// bf != 0
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// dh != 0
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// df != bh // kollinear (b/d != f/h)
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const float sx1 = l1.p1.x; // a
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const float sy1 = l1.p1.y; // e
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const float dx1 = l1.p2.x - l1.p1.x; // b
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const float dy1 = l1.p2.y - l1.p1.y; // f
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const float sx2 = l2.p1.x; // c
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const float sy2 = l2.p1.y; // g
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const float dx2 = l2.p2.x - l2.p1.x; // d
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const float dy2 = l2.p2.y - l2.p1.y; // h
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// collinear?
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const float a1 = dx2*dy1;
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const float a2 = dx1*dy2;
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if (std::abs(a1-a2) < 0.0001) {return false;}
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const float v = (dy1*(sx1-sx2) + dx1*(sy2-sy1)) / (dx2*dy1 - dx1*dy2);
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const float u = (dy2*(sx1-sx2) + dx2*(sy2-sy1)) / (dx2*dy1 - dx1*dy2);
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//const float x = sx2 + v*dx2;
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//const float y = sy2 + v*dy2;
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const float x = sx1 + u*dx1;
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const float y = sy1 + u*dy1;
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if (!limit || (u >= 0 && v >= 0 && u <= 1 && v <= 1)) {
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pos = Point2(x,y);
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return true;
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}
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return false;
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}
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#endif // LINE2D_H
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