flying-balls/polygons.h

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#ifndef POLYGONS_H_INCLUDED
#define POLYGONS_H_INCLUDED
#include "vec2d.h"
#include <cmath>
#include <gtk/gtk.h>
#include <utility>
#include <vector>
typedef std::pair<vec2d, vec2d> rect;
class polygon {
private:
void update_global_points();
public:
vec2d center;
double angle;
std::vector<vec2d> points;
double inertia;
double mass;
std::vector<vec2d> global_points = points;
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vec2d speed;
double angular_speed;
void draw(cairo_t* cr) const;
void draw_bounding_rect(cairo_t* cr) const;
rect get_bounding_box() const {
vec2d tl{INFINITY, INFINITY}, tr{-INFINITY, -INFINITY};
for (auto& point : this->global_points) {
if (point.x < tl.x)
tl.x = point.x;
if (point.y < tl.y)
tl.y = point.y;
if (point.x > tr.x)
tr.x = point.x;
if (point.y > tr.y)
tr.y = point.y;
}
return {tl, tr};
}
polygon& set_center(vec2d c) {
center = c;
update_global_points();
return *this;
}
polygon& set_speed(vec2d s) {
speed = s;
return *this;
}
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polygon& set_angular_speed(double as) {
angular_speed = as;
return *this;
}
polygon& set_angle(double a) {
angle = a;
update_global_points();
return *this;
}
polygon& set_mass(double m) {
mass = m;
return *this;
}
polygon& translate(vec2d delta) {
center += delta;
update_global_points();
return *this;
}
polygon& rotate(double delta) {
angle += delta;
update_global_points();
return *this;
}
vec2d centroid() const {
double x = 0, y = 0;
for (auto& p : global_points)
x += p.x, y += p.y;
return vec2d{x, y} / points.size();
}
};
extern polygon* polygons;
extern uint n_polygons;
extern void polygons_init_state();
extern void polygons_update_state();
extern void polygons_draw(cairo_t* cr);
#endif