[WIP] Initial commit

2021-08-24 05:26:58 +01:00 · 2021-08-24 05:26:58 +01:00 · fc8f7775ba
commit fc8f7775ba
4 changed files with 2968 additions and 0 deletions
--- a/.gitignore
+++ b/.gitignore
@ -0,0 +1 @@
+/target
--- a/Cargo.lock
+++ b/Cargo.lock
--- a/Cargo.toml
+++ b/Cargo.toml
@ -0,0 +1,10 @@
+[package]
+name = "sketch-gravity"
+version = "0.1.0"
+edition = "2018"
+
+# See more keys and their definitions at https://doc.rust-lang.org/cargo/reference/manifest.html
+
+[dependencies]
+nannou = "0.17.1"
+rayon = "1.5.1"
--- a/src/main.rs
+++ b/src/main.rs
@ -0,0 +1,84 @@
+use nannou::prelude::*;
+use rayon::prelude::*;
+
+fn main() {
+    nannou::app(model).update(update).simple_window(view).run();
+}
+
+#[derive(Clone)]
+struct Body {
+    pos: DVec2,
+    vel: DVec2,
+}
+
+struct Model {
+    bodies: Vec<Body>,
+}
+
+fn model(_app: &App) -> Model {
+    let mut bodies = Vec::new();
+
+    let mut theta = 0.0;
+    for r in 0..512 {
+        let r = r as f64;
+        let r = 10.0 * r.sqrt();
+
+        bodies.push(Body {
+            pos: (r * theta.cos(), r * theta.sin()).into(),
+            vel: (0.0, 0.0).into(),
+        });
+
+        theta += 1.94161103873;
+    }
+
+    Model { bodies }
+}
+
+fn update(app: &App, model: &mut Model, _update: Update) {
+    const G: f64 = 6.67408e-11;
+
+    let bodies = model.bodies.clone();
+    let delta_t = app.duration.since_prev_update.as_secs_f64();
+
+    model
+        .bodies
+        .par_iter_mut()
+        .enumerate()
+        .for_each(|(i, body)| {
+            let mut acc: DVec2 = (0.0, 0.0).into();
+
+            bodies.iter().enumerate().for_each(|(j, other_body)| {
+                if i == j {
+                    return;
+                }
+
+                let delta = other_body.pos - body.pos;
+                let dist_sq = body.pos.distance_squared(other_body.pos);
+
+                if dist_sq < 1.0 {
+                    return;
+                }
+
+                let force = G * /* × mass_a × mass_b = */ 1e14 / dist_sq;
+
+                acc += delta * force / dist_sq.sqrt();
+                acc -= 0.5 * delta / (dist_sq * 0.5);
+            });
+
+            body.vel += acc * delta_t;
+            body.pos += body.vel * delta_t;
+        });
+}
+
+fn view(app: &App, model: &Model, frame: Frame) {
+    // let t = app.duration.since_start.as_secs_f64();
+
+    let draw = app.draw();
+    draw.background().color(BLACK);
+
+    for body in model.bodies.iter() {
+        draw.ellipse().w_h(10.0, 10.0).xy(body.pos.as_f32());
+    }
+
+    draw.to_frame(app, &frame).unwrap();
+}