ry-physics

Physics module for Ry-Dit — Projectile motion, Gravity, N-body simulation

Overview

ry-physics is a physics simulation library for the Ry-Dit game engine. It provides projectile motion calculations, gravitational N-body simulations, and more — all accessible via a clean JSON-based API.

Installation

[dependencies]
ry-physics = "0.7.34"
ry-core = "0.8.2"
serde_json = "1.0"

Quick Start

use ry_physics::PhysicsModule;
use ry_core::RyditModule;
use serde_json::json;

let module = PhysicsModule;

// Projectile motion: x0, y0, velocity (m/s), angle (degrees)
let result = module.execute("projectile", json!([0.0, 0.0, 50.0, 45.0]))?;
// Returns: [x_final, y_final, flight_time, max_height, range]

// N-body gravity: 2 bodies
let force = module.execute("nbody_2", json!([100.0, 200.0, 0.0, 0.0, 10.0, 0.0, 1.0]))?;
// Returns: [fx1, fy1, fx2, fy2, distance]

// N-body simulation: multiple bodies over time
let bodies = json!([
    [[100.0, 0.0, 0.0, 0.0, 0.0, 0.0],   // mass, x, y, vx, vy, is_static
     [100.0, 10.0, 0.0, 0.0, 0.0, 0.0],
     [50.0, 5.0, 5.0, 0.0, 0.0, 0.0]],
    0.016,   // dt (delta time)
    1.0      // G (gravitational constant)
]);
let result = module.execute("nbody_simulate", bodies)?;
// Returns: [[x, y, vx, vy], ...] updated positions

API Reference

Projectile Motion

module.execute("projectile", json!([x0, y0, velocity, angle_degrees]))

Returns: [x_final, y_final, flight_time, max_height, range]

Formulas:

• Flight time: 2 * vy / g
• Max height: vy² / (2 * g)
• Range: vx * flight_time

N-Body (2 Bodies)

module.execute("nbody_2", json!([m1, m2, x1, y1, x2, y2, G]))

Returns: [fx1, fy1, fx2, fy2, distance]

Formula: F = G * m1 * m2 / r²

N-Body Simulation (Multiple Bodies)

module.execute("nbody_simulate", json!([bodies, dt, G]))

Returns: [[x, y, vx, vy], ...] — updated positions and velocities

Algorithm: O(n²) pairwise gravitational computation with Euler integration.

Examples

Ball Trajectory

// Kick a ball at 20 m/s, 30 degrees from ground level
let result = PhysicsModule.execute("projectile", json!([0.0, 0.0, 20.0, 30.0]));

let data = result.unwrap().as_array().unwrap();
let flight_time = data[2].as_f64().unwrap();
let max_height = data[3].as_f64().unwrap();
let range = data[4].as_f64().unwrap();

println!("Ball flies for {:.2}s, reaches {:.2}m high, lands {:.2}m away",
    flight_time, max_height, range);

Orbital Simulation

// Sun + Earth + Moon simplified
let bodies = json!([
    // Sun: massive, static at center
    [1000.0, 0.0, 0.0, 0.0, 0.0, 1.0],
    // Earth: orbiting
    [10.0, 100.0, 0.0, 0.0, 3.0, 0.0],
    // Moon: orbiting Earth
    [1.0, 105.0, 0.0, 0.0, 5.0, 0.0],
]);

for step in 0..1000 {
    let result = PhysicsModule.execute("nbody_simulate", json!([bodies, 0.01, 1.0])).unwrap();
    println!("Step {}: {:?}", step, result);
}

LAZOS Protocol

# Projectile
echo '{"method":"physics::projectile","params":[0,0,50,45]}' | rydit-rs --lazos

# N-body gravity
echo '{"method":"physics::nbody_2","params":[100,200,0,0,10,0,1]}' | rydit-rs --lazos

# N-body simulation
echo '{"method":"physics::nbody_simulate","params":[[[100,0,0,0,0,0],[100,10,0,0,0,0]],0.016,1]}' | rydit-rs --lazos

Performance

• O(n²) N-body: Suitable for up to ~500 bodies in real-time
• Zero allocations in projectile calculation (pure math)
• 6 unit tests ensuring correctness across all functions

Dependencies

Roadmap

• RK4 integration (more accurate than Euler)
• Collision detection between bodies
• Soft-body physics
• Fluid dynamics (simplified)
• Electromagnetism simulation

Contributing

Contributions are welcome! This crate is part of the Ry-Dit game engine project.

• Repository: https://github.com/lapumlbb18-blip/Ry-dit
• Issues: https://github.com/lapumlbb18-blip/Ry-dit/issues
• Pull Requests: Welcome!

Please read CONTRIBUTING.md for guidelines.

License

MIT License - See LICENSE for details.

ry-physics — Physics simulations for Ry-Dit game engine 🚀🌍

6 tests · 296 lines · Projectile + N-body gravity