Generator now makes the polygons origin at their center of mass, easier for rotation

This commit is contained in:
Karma Riuk 2023-03-20 15:33:35 +01:00
parent e6a3979de1
commit d6bf526459
4 changed files with 68 additions and 18 deletions

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@ -44,6 +44,7 @@ void update_state() {
check_collisions(); check_collisions();
for (unsigned int i = 0; i < n_balls; ++i) for (unsigned int i = 0; i < n_balls; ++i)
ball_update_state(balls + i); ball_update_state(balls + i);
polygons_update_state();
spaceship_update_state(); spaceship_update_state();
} }

15
matrix.h Normal file
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@ -0,0 +1,15 @@
#ifndef MATRIX_H_INCLUDED
#define MATRIX_H_INCLUDED
#include "vec2d.h"
class matrix {
public:
vec2d b1, b2;
};
inline vec2d operator*(matrix m, vec2d v) {
return vec2d{v.x * m.b1.x + v.y * m.b2.x, v.x * m.b1.y + v.y * m.b2.y};
}
#endif

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@ -3,27 +3,35 @@
#include <cassert> #include <cassert>
#include <cmath> #include <cmath>
#define PI 3.141592653589793238462643323
static double to_rad(double angle_in_deg) { static double to_rad(double angle_in_deg) {
static double PI_180 = PI / 180; static double PI_180 = M_PI / 180;
return angle_in_deg * PI_180; return angle_in_deg * PI_180;
} }
polygon poly_generate::rectangle(double width, double height) { polygon poly_generate::rectangle(double width, double height) {
assert(width > 0); assert(width > 0);
assert(height > 0); assert(height > 0);
return polygon{ return polygon{{0, 0},
{0, 0}, 0, {{0, 0}, {width, 0}, {width, height}, {0, height}}}; 0,
{{-width / 2, -height / 2},
{width / 2, -height / 2},
{width / 2, height / 2},
{-width / 2, height / 2}}};
} }
polygon poly_generate::triangle(double side1, double side2, double angle) { polygon poly_generate::triangle(double side1, double side2, double angle) {
assert(side1 > 0); assert(side1 > 0);
assert(side2 > 0); assert(side2 > 0);
return polygon{{0, 0}, vec2d points[] = {{0, 0},
0,
{{0, 0},
{side1, 0}, {side1, 0},
{side2 * std::cos(to_rad(angle)), {side2 * std::cos(to_rad(angle)), side2 * std::sin(to_rad(angle))}};
side2 * std::sin(to_rad(angle))}}};
vec2d barycenter = {
(points[0].x + points[1].x + points[2].x) / 3,
(points[0].y + points[1].y + points[2].y) / 3,
};
for (unsigned int i = 0; i < 3; ++i)
points[i] -= barycenter;
return polygon{{0, 0}, 0, {std::begin(points), std::end(points)}};
} }

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@ -1,7 +1,9 @@
#include "polygons.h" #include "polygons.h"
#include "matrix.h"
#include "polygon_generator.h" #include "polygon_generator.h"
#include <cmath>
#include <iostream> #include <iostream>
polygon* polygons = nullptr; polygon* polygons = nullptr;
@ -10,19 +12,43 @@ uint n_polygons = 3;
void polygons_init_state() { void polygons_init_state() {
polygons = new polygon[n_polygons]; polygons = new polygon[n_polygons];
polygons[0] = poly_generate::triangle(200, 200, 30).set_center({300, 200}); polygons[0] = poly_generate::triangle(150, 150, 30)
polygons[1] = poly_generate::square(200).set_center({100, 400}); .set_center({400, 300})
polygons[2] = poly_generate::rectangle(200, 100).set_center({400, 400}); .set_angle(90);
polygons[1] = poly_generate::square(200).set_center({200, 600});
polygons[2] = poly_generate::rectangle(200, 100).set_center({600, 600});
}
static double to_rad(double angle_in_deg) {
static double PI_180 = M_PI / 180;
return angle_in_deg * PI_180;
}
void polygons_update_state() {
static double angle = 0;
for (polygon* p = polygons; p != polygons + n_polygons; ++p) {
p->rotate(1);
p->translate({2 * std::cos(angle), 0});
}
angle -= .03;
} }
void polygon::draw(cairo_t* cr) const { void polygon::draw(cairo_t* cr) const {
const vec2d& center = this->center; const vec2d& center = this->center;
cairo_set_source_rgb(cr, 1, 1, 1); cairo_set_source_rgb(cr, 1, 1, 1);
for (auto& point : this->points) double cos_theta = std::cos(to_rad(this->angle));
cairo_line_to(cr, center.x + point.x, center.y + point.y); double sin_theta = std::sin(to_rad(this->angle));
cairo_line_to(
cr, center.x + this->points[0].x, center.y + this->points[0].y); matrix rotation = matrix{{cos_theta, sin_theta}, {-sin_theta, cos_theta}};
vec2d final_point;
for (auto& point : this->points) {
final_point = rotation * point;
cairo_line_to(cr, center.x + final_point.x, center.y + final_point.y);
}
final_point = rotation * this->points[0];
cairo_line_to(cr, center.x + final_point.x, center.y + final_point.y);
cairo_stroke(cr); cairo_stroke(cr);
} }