parsnip_plucker/src/physics.rs

use bevy::{ecs::component::Component, math::I64Vec2};

const MAX_SPEED: i64 = 256;

#[derive(Default, Debug, Component)]
pub struct PhysicsBody2D {
    pub pos: I64Vec2,
    pub vel: I64Vec2,
}

impl PhysicsBody2D {
    pub fn tick(&mut self) {
        self.pos += self.vel;
    }

    pub fn add_vel(&mut self, force: I64Vec2) {
        let mut vel = self.vel + force;
        if vel.length_squared() >= MAX_SPEED.pow(2) {
            let l = vel.length_squared();
            let x = vel.x * vel.x;
            let y = vel.y * vel.y;

            vel.x = match vel.x {
                ..0 => (x * -MAX_SPEED) / l,
                _ => (x * MAX_SPEED) / l,
            };
            vel.y = match vel.y {
                ..0 => (y * -MAX_SPEED) / l,
                _ => (y * MAX_SPEED) / l,
            };
        }
        self.vel = vel;
    }
}