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Now the borders of the windows are walls of infinite mass

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This commit is contained in:
Karma Riuk 2023-04-10 14:40:16 +02:00
parent c7b9500bc4
commit 1c58530e98
1 changed files with 58 additions and 47 deletions
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105
polygons.cc
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@ -10,24 +10,37 @@
#include <utility>
polygon* polygons = nullptr;
uint n_polygons = 2;
uint n_polygons = 6;
void polygons_init_state() {
polygons = new polygon[n_polygons];
polygons[0] = poly_generate::square(100, 1)
.set_center({200, 530})
.set_angle(-30)
.set_angular_speed(0)
.set_speed({200, -200});
int wall_thickness = 50;
// north wall
polygons[0] = poly_generate::rectangle(width, wall_thickness, INFINITY)
.set_center({width / 2., -wall_thickness / 2.});
// south wall
polygons[1] = poly_generate::rectangle(width, wall_thickness, INFINITY)
.set_center({width / 2., height + wall_thickness / 2.});
// west wall
polygons[2] = poly_generate::rectangle(wall_thickness, height, INFINITY)
.set_center({-wall_thickness / 2., height / 2.});
// east wall
polygons[3] = poly_generate::rectangle(wall_thickness, height, INFINITY)
.set_center({width + wall_thickness / 2., height / 2.});
// polygons[0] = poly_generate::triangle(150, 150, 30)
// .set_center({200, 400})
// .set_angle(13)
// .set_angular_speed(10)
// .set_speed({200, 50});
polygons[1] = poly_generate::rectangle(50, height / 2., INFINITY)
polygons[4] = poly_generate::rectangle(50, height / 2., INFINITY)
.set_center({25 + width * 1. / 2, height / 2.})
.set_angle(0);
polygons[5] = poly_generate::square(100, 1)
.set_center({200, 200})
.set_angle(-30)
.set_angular_speed(0)
.set_speed({200, -200});
}
static double to_rad(double angle_in_deg) {
@ -63,55 +76,57 @@ static double impulse_parameter(vec2d v_ab1,
double I_b,
double e) {
double nominator = -(1 + e) * vec2d::dot(v_ab1, n);
double denominator = 1 / m_a + 1 / m_b +
std::pow(vec2d::cross(r_ap, n), 2) / I_a +
std::pow(vec2d::cross(r_bp, n), 2) / I_b;
double r_ap_cross_n = vec2d::cross(r_ap, n);
double r_bp_cross_n = vec2d::cross(r_bp, n);
double denominator = 1 / m_a + 1 / m_b + r_ap_cross_n * r_ap_cross_n / I_a +
r_bp_cross_n * r_bp_cross_n / I_b;
return nominator / denominator;
}
static int8_t sign(double d) {
return d >= 0 ? 1 : -1;
}
static void handle_collision(collision& c, polygon* a, polygon* b) {
// see https://www.myphysicslab.com/engine2D/collision-en.html for the
// formulas
// avoid the polygons getting stuck if, on the frame after the impact,
// the polygon a is still inside of b
// std::cout << "sign(v_a x n) = " << << std::endl;
// if (vec2d::dot(a->speed, c.n) > 0 &&
// vec2d::dot(a->speed, c.impact_point - a->centroid()) > 0 &&
// sign(vec2d::cross(c.n, a->speed)) == -sign(a->angular_speed))
// // might have to tweak this condition
// return;
double omega_a1 = to_rad(a->angular_speed);
double omega_b1 = to_rad(b->angular_speed);
vec2d r_ap = c.impact_point - a->centroid();
vec2d v_ap1 = a->speed + vec2d::cross(omega_a1, r_ap);
std::cout << " "
<< "r_ap = " << r_ap << std::endl;
std::cout << " "
<< "v_ap1 = " << v_ap1 << std::endl;
std::cout << " r_ap = " << r_ap << std::endl;
std::cout << " v_ap1 = " << v_ap1 << std::endl;
vec2d r_bp = c.impact_point - b->centroid();
vec2d v_bp1 = b->speed + vec2d::cross(omega_b1, r_bp);
std::cout << " "
<< "r_bp = " << r_bp << std::endl;
std::cout << " "
<< "v_bp1 = " << v_bp1 << std::endl;
std::cout << " r_bp = " << r_bp << std::endl;
std::cout << " v_bp1 = " << v_bp1 << std::endl;
vec2d v_ab1 = v_ap1 - v_bp1;
std::cout << " "
<< "v_ab1 = " << v_ab1 << std::endl;
std::cout << " v_ab1 = " << v_ab1 << std::endl;
double I_a = a->inertia, I_b = b->inertia;
std::cout << " Parameters for j: " << std::endl;
std::cout << " "
<< "v_ab1 = " << v_ab1 << std::endl;
std::cout << " "
<< "n = " << c.n << std::endl;
std::cout << " "
<< "m_a = " << a->mass << std::endl;
std::cout << " "
<< "m_b = " << b->mass << std::endl;
std::cout << " "
<< "r_ap = " << r_ap << std::endl;
std::cout << " "
<< "r_bp = " << r_bp << std::endl;
std::cout << " "
<< "I_a = " << I_a << std::endl;
std::cout << " "
<< "I_b = " << I_b << std::endl;
std::cout << " v_ab1 = " << v_ab1 << std::endl;
std::cout << " n = " << c.n << std::endl;
std::cout << " m_a = " << a->mass << std::endl;
std::cout << " m_b = " << b->mass << std::endl;
std::cout << " r_ap = " << r_ap << std::endl;
std::cout << " r_bp = " << r_bp << std::endl;
std::cout << " I_a = " << I_a << std::endl;
std::cout << " I_b = " << I_b << std::endl;
double j = impulse_parameter(
v_ab1, c.n, a->mass, b->mass, r_ap, r_bp, I_a, I_b, 1);
@ -119,17 +134,13 @@ static void handle_collision(collision& c, polygon* a, polygon* b) {
vec2d v_a2 = a->speed + j * c.n / a->mass;
vec2d v_b2 = b->speed - j * c.n / b->mass;
std::cout << " "
<< "v_a2 = " << v_a2 << std::endl;
std::cout << " "
<< "v_b2 = " << v_b2 << std::endl;
std::cout << " v_a2 = " << v_a2 << std::endl;
std::cout << " v_b2 = " << v_b2 << std::endl;
double omega_a2 = omega_a1 + vec2d::cross(r_ap, j * c.n) / I_a;
double omega_b2 = omega_b1 - vec2d::cross(r_bp, j * c.n) / I_b;
std::cout << " "
<< "omega_a2 = " << omega_a2 << std::endl;
std::cout << " "
<< "omega_b2 = " << omega_b2 << std::endl;
std::cout << " omega_a2 = " << omega_a2 << std::endl;
std::cout << " omega_b2 = " << omega_b2 << std::endl;
a->speed = v_a2;
a->angular_speed = to_deg(omega_a2);
@ -148,7 +159,7 @@ static void check_collisions(polygon* current_p) {
rect other_bound = other_p->get_bounding_box();
if (bounding_rects_collide(cur_bound, other_bound) ||
bounding_rects_collide(other_bound, cur_bound)) {
// std::cout << "Bounding boxes do collide" << std::endl;
std::cout << "Bounding boxes do collide" << std::endl;
collision c = collides(*current_p, *other_p);
if (c.collides) {
std::cout << "colliding" << std::endl;
@ -188,7 +199,7 @@ void polygons_update_state() {
for (polygon* p = polygons; p != polygons + n_polygons; ++p) {
if (p->mass == INFINITY) // immovable objects don't need to be updated
continue;
check_border_collision(p);
// check_border_collision(p);
check_collisions(p);
p->rotate(delta * p->angular_speed);
p->translate(delta * p->speed);
@ -223,7 +234,7 @@ void polygon::draw_bounding_rect(cairo_t* cr) const {
}
void polygon::draw(cairo_t* cr) const {
this->draw_bounding_rect(cr);
// this->draw_bounding_rect(cr);
cairo_set_source_rgb(cr, 1, 1, 1);