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add nature::gravitational_acceleration, incl. test

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yuni 2024-06-08 03:15:25 +02:00
parent c6750eae46
commit 169b9ee257
1 changed files with 18 additions and 0 deletions
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18
src/nature.rs
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@ -28,9 +28,11 @@ pub const G: f64 = 6.6743015e-11; // Gravitational constant in Nm²/kg²
pub const SOL_RADIUS: f64 = 696_300_000.0;
pub const JUPITER_RADIUS: f64 = 71_492_000.0;
pub const JUPITER_RING_RADIUS: f64 = 229_000_000.0;
pub const EARTH_RADIUS: f64 = 6_371_000.0;
pub const SOL_MASS: f64 = 1.9885e30;
pub const JUPITER_MASS: f64 = 1.8982e27;
pub const EARTH_MASS: f64 = 5.972168e24;
// Each star's values: (x, y, z, magnitude, color index, distance, name)
pub const STARS: &[(f32, f32, f32, f32, f32, f32, &str)] = &include!("data/stars.in");
@ -180,6 +182,22 @@ pub fn orbital_velocity(coords: Vec3, mass: f64) -> Vec3 {
return perpendicular * speed;
}
/// Calculates the acceleration towards a mass in m/s
pub fn gravitational_acceleration(coords: Vec3, mass: f64) -> Vec3 {
let r_squared = coords.length_squared() as f64;
let acceleration_magnitude = G * mass / r_squared;
return -acceleration_magnitude as f32 * (coords / r_squared.sqrt() as f32);
}
#[test]
fn test_gravitational_acceleration() {
let coords = Vec3::new(EARTH_RADIUS as f32, 0.0, 0.0);
let mass = EARTH_MASS;
let g = gravitational_acceleration(coords, mass);
let g_rounded = (g * 10.0).round() / 10.0;
assert_eq!(g_rounded, Vec3::new(-9.8, 0.0, 0.0));
}
pub fn phase_dist_to_coords(phase_radians: f64, distance: f64) -> DVec3 {
return DVec3::new(
distance * phase_radians.cos(),