orbital mechanics :D

main
Charlotte Som 2021-08-28 02:22:58 +01:00
parent fc8f7775ba
commit 6bb5d90d54
5 changed files with 79 additions and 16 deletions

4
.gitignore vendored
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@ -1 +1,5 @@
/target /target
# ffmpeg -framerate 60 -i recordings/%05d.png -pix_fmt yuv420p recording.mp4
/recordings
/recording.mp4

1
Cargo.lock generated
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@ -2240,6 +2240,7 @@ name = "sketch-gravity"
version = "0.1.0" version = "0.1.0"
dependencies = [ dependencies = [
"nannou", "nannou",
"once_cell",
"rayon", "rayon",
] ]

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@ -7,4 +7,5 @@ edition = "2018"
[dependencies] [dependencies]
nannou = "0.17.1" nannou = "0.17.1"
once_cell = "1.8.0"
rayon = "1.5.1" rayon = "1.5.1"

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@ -1,14 +1,21 @@
use nannou::prelude::*; use nannou::prelude::*;
use rayon::prelude::*; use rayon::prelude::*;
mod recording;
fn main() { fn main() {
nannou::app(model).update(update).simple_window(view).run(); nannou::app(model)
.size(1440, 1440)
.update(update)
.simple_window(view)
.run();
} }
#[derive(Clone)] #[derive(Clone)]
struct Body { struct Body {
pos: DVec2, pos: DVec2,
vel: DVec2, vel: DVec2,
mass: i64,
} }
struct Model { struct Model {
@ -18,17 +25,33 @@ struct Model {
fn model(_app: &App) -> Model { fn model(_app: &App) -> Model {
let mut bodies = Vec::new(); let mut bodies = Vec::new();
let mut theta = 0.0; const MASS_SUN: i64 = 150000000000000000;
for r in 0..512 {
let r = r as f64; bodies.push(Body {
let r = 10.0 * r.sqrt(); pos: (0.0, 0.0).into(),
vel: (0.0, 0.0).into(),
mass: MASS_SUN,
});
const G: f64 = 6.67408e-11;
const COPIES: i32 = 1;
let d_theta: f64 = (360.0 / COPIES as f64).to_radians();
for i in 0..COPIES {
let theta = i as f64 * d_theta;
for i in 10..250 {
let r = 5.0 * i as f64;
let m = 10000000 / i;
bodies.push(Body { bodies.push(Body {
pos: (r * theta.cos(), r * theta.sin()).into(), pos: (r * theta.cos(), r * theta.sin()).into(),
vel: (0.0, 0.0).into(), vel: (0.0, (G * MASS_SUN as f64 / r).sqrt()).into(),
mass: m,
}); });
}
theta += 1.94161103873;
} }
Model { bodies } Model { bodies }
@ -38,7 +61,7 @@ fn update(app: &App, model: &mut Model, _update: Update) {
const G: f64 = 6.67408e-11; const G: f64 = 6.67408e-11;
let bodies = model.bodies.clone(); let bodies = model.bodies.clone();
let delta_t = app.duration.since_prev_update.as_secs_f64(); let delta_t = recording::delta_t(&app);
model model
.bodies .bodies
@ -59,10 +82,9 @@ fn update(app: &App, model: &mut Model, _update: Update) {
return; return;
} }
let force = G * /* × mass_a × mass_b = */ 1e14 / dist_sq; let acceleration = G * other_body.mass as f64 / dist_sq;
acc += delta * force / dist_sq.sqrt(); acc += delta * acceleration / dist_sq.sqrt();
acc -= 0.5 * delta / (dist_sq * 0.5);
}); });
body.vel += acc * delta_t; body.vel += acc * delta_t;
@ -73,12 +95,14 @@ fn update(app: &App, model: &mut Model, _update: Update) {
fn view(app: &App, model: &Model, frame: Frame) { fn view(app: &App, model: &Model, frame: Frame) {
// let t = app.duration.since_start.as_secs_f64(); // let t = app.duration.since_start.as_secs_f64();
let draw = app.draw(); let draw = app.draw().scale(2.0);
draw.background().color(BLACK); draw.background().color(BLACK);
for body in model.bodies.iter() { for body in model.bodies.iter() {
draw.ellipse().w_h(10.0, 10.0).xy(body.pos.as_f32()); let diameter = (body.mass as f32).log10(); // should be proportional to cuberoot but this is so we can actually see the small ones
draw.ellipse().w_h(diameter, diameter).xy(body.pos.as_f32());
} }
draw.to_frame(app, &frame).unwrap(); draw.to_frame(app, &frame).unwrap();
recording::record(app, &frame);
} }

33
src/recording.rs Normal file
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@ -0,0 +1,33 @@
use nannou::prelude::*;
use once_cell::sync::Lazy;
static RECORDING: Lazy<bool> = Lazy::new(|| {
let args: Vec<String> = std::env::args().collect();
args.iter().any(|s| s == "--record")
});
pub fn record(app: &App, frame: &Frame) {
if !*RECORDING {
return;
}
// save frame
let path = app
.project_path()
.expect("failed to locate `project_path`")
// Capture all frames to a directory called `/<path_to_nannou>/nannou/simple_capture`.
.join("recordings")
// Name each file after the number of the frame.
.join(format!("{:05}", frame.nth()))
// The extension will be PNG. We also support tiff, bmp, gif, jpeg, webp and some others.
.with_extension("png");
println!("frame: {} {:.05}", frame.nth(), frame.nth() as f32 / 60.0);
app.main_window().capture_frame(path);
}
pub fn delta_t(app: &App) -> f64 {
if *RECORDING {
1.0 / 60.0
} else {
app.duration.since_prev_update.as_secs_f64()
}
}