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use raylib::prelude::*;
use physics::force::{drag::Drag, gravity::Gravity, spring::Spring};
use physics::nalgebra::Point as PointBase;
use physics::particle_system::{Particle, ParticleSystem};
use physics::algebra::{Point, Scalar, Vector, N};
use physics::renderer::Camera;
use physics::solver::Solver;
const SCALE: i32 = 5;
fn screen_space_to_raylib(p: PointBase<Scalar, 2>, d: &RaylibDrawHandle) -> PointBase<i32, 2> {
PointBase::<i32, 2>::new(
d.get_screen_width() / 2 + p.x as i32 * SCALE,
d.get_screen_height() / 2 - p.y as i32 * SCALE,
)
}
fn raylib_to_screen_space(p: PointBase<i32, 2>, d: &RaylibDrawHandle) -> PointBase<Scalar, 2> {
PointBase::<Scalar, 2>::new(
((p.x - d.get_screen_width() / 2) / SCALE) as Scalar,
((p.y - d.get_screen_height() / 2) / -SCALE) as Scalar,
)
}
fn main() {
let dt = 0.0001;
let mut system = ParticleSystem {
particles: vec![
Particle::new(Point::origin(), 4.0),
Particle::new(Point::new(-30.0, 0.0), 15.0),
Particle::new(Point::new(20.0, 0.0), 30.0),
Particle::new(Point::new(5.0, 20.0), 50.0),
Particle::new(Point::origin(), 25.0),
Particle::new(Point::new(50.0, 0.0), 10.0),
Particle::new(Point::new(-100.0, -100.0), 100.0),
],
constraints: vec![],
forces: vec![
Box::new(Gravity {
vector: Vector::y() * -9.8,
}),
Box::new(Drag { coefficient: 0.2 }),
Box::new(Spring {
particle_ids: [4, 2],
spring_constant: 0.75,
damping_constant: 0.1,
rest_length: 20.0,
}),
],
t: 0.0,
};
system.add_anchor_constraint(0);
system.add_beam_constraint([0, 2]);
system.add_beam_constraint([1, 2]);
system.add_beam_constraint([1, 3]);
system.add_beam_constraint([2, 3]);
system.add_slider_constraint(5, Vector::x());
system.add_beam_constraint([5, 4]);
let mut selected_particle_id = None;
let (mut rl, thread) = raylib::init()
.size(640, 480)
.title("Physics simulation")
.resizable()
.build();
while !rl.window_should_close() {
let mut d = rl.begin_drawing(&thread);
d.clear_background(Color::WHITE);
d.draw_text(
format!(
"Time: {:03.3}\n\nFPS: {}\n\nKinetic energy: {:03.0}",
system.t,
d.get_fps(),
system.get_kinetic_energy()
)
.as_str(),
12,
12,
20,
Color::BLACK,
);
let camera = Camera::new(Point::origin(), Vector::y(), Vector::x());
match selected_particle_id {
Some(particle_id) => {
// let p: &Particle = &system.particles[particle_id];
let mouse_point = PointBase::<i32, 2>::new(d.get_mouse_x(), d.get_mouse_y());
let screen_space = raylib_to_screen_space(mouse_point, &d);
let world_mouse = camera.screen_space_to_world(screen_space);
let mouse_particle_id = system.particles.len() - 1;
system.particles[mouse_particle_id].position = world_mouse;
system.forces.push(Box::new(Spring {
particle_ids: [mouse_particle_id, particle_id],
spring_constant: 0.99,
damping_constant: 0.99,
rest_length: 1.0,
}));
}
None => (),
}
for _ in 0..10 {
system.apply_forces();
system.enforce_constraints(dt);
system.step(dt);
}
match selected_particle_id {
Some(_) => {
system.forces.pop();
}
None => (),
}
if d.is_mouse_button_released(MouseButton::MOUSE_BUTTON_LEFT) {
selected_particle_id = None
}
for (particle_id, particle) in system.particles.iter().enumerate() {
let position =
screen_space_to_raylib(camera.world_to_screen_space(particle.position), &d);
let radius = particle.mass.powf(1.0 / (N as f64)) as f32 * SCALE as f32;
if d.is_mouse_button_down(MouseButton::MOUSE_BUTTON_LEFT)
&& selected_particle_id.is_none()
{
let mouse_point =
PointBase::<f32, 2>::new(d.get_mouse_x() as f32, d.get_mouse_y() as f32);
let position = PointBase::<f32, 2>::new(position.x as f32, position.y as f32);
if (position - mouse_point).norm() < radius {
selected_particle_id = Some(particle_id)
}
}
d.draw_circle(
position.x,
position.y,
radius,
if selected_particle_id.is_some_and(|v| v == particle_id) {
Color::RED
} else {
Color::BLACK
},
);
}
for c in &system.constraints {
let particle_ids = c.get_particles();
if particle_ids.len() == 2 {
let a = screen_space_to_raylib(system.particles[particle_ids[0]].position, &d);
let b = screen_space_to_raylib(system.particles[particle_ids[1]].position, &d);
d.draw_line(a.x, a.y, b.x, b.y, Color::GRAY);
}
}
{
// Hard-coded spring
let particle_ids = [4, 2];
let a = screen_space_to_raylib(system.particles[particle_ids[0]].position, &d);
let b = screen_space_to_raylib(system.particles[particle_ids[1]].position, &d);
d.draw_line(a.x, a.y, b.x, b.y, Color::GREEN);
}
{
// Hard-coded spring
match selected_particle_id {
Some(id) => {
let mouse_particle_id = system.particles.len() - 1;
let a = screen_space_to_raylib(system.particles[id].position, &d);
let b =
screen_space_to_raylib(system.particles[mouse_particle_id].position, &d);
d.draw_line(a.x, a.y, b.x, b.y, Color::GREEN);
}
None => (),
}
}
}
}
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