bevy_heavy

bevy_heavy is a crate for computing mass properties (mass, angular inertia, and center of mass) for the geometric primitives in the Bevy game engine. This is typically required for things like physics simulations.

Features

• MassProperties2d and MassProperties3d structs containing the mass, angular inertia, and local center of mass
• Mass property computation for all of Bevy's geometric primitives
• Eigensolver for symmetric 3x3 matrices
• Support for bevy_reflect and serde through the bevy_reflect and serialize feature flags

Usage

Mass properties can be computed individually for shapes using the mass, angular_inertia, and center_of_mass methods:

use bevy_heavy::{ComputeMassProperties2d, MassProperties2d};
use bevy_math::{primitives::Rectangle, Vec2};

let rectangle = Rectangle::new(2.0, 1.0);
let density = 2.0;

let mass = rectangle.mass(density);
let angular_inertia = rectangle.angular_inertia(mass);
let center_of_mass = rectangle.center_of_mass();

You can also compute all mass properties at once, returning MassProperties2d for 2D shapes, or MassProperties3d for 3D shapes. This can be more efficient when more than one property is needed.

let mass_props = rectangle.mass_properties(density);

The mass property types have several helper methods for various transformations and operations:

let shifted_inertia = mass_props.shifted_angular_inertia(Vec2::new(-3.5, 1.0));
let global_center_of_mass = mass_props.global_center_of_mass(Vec2::new(5.0, 7.5));

You can also add and subtract mass properties:

let mass_props_2 = MassProperties2d::new(mass, angular_inertia, Vec2::new(0.0, 1.0));
let sum = mass_props + mass_props_2;
approx::assert_relative_eq!(sum - mass_props_2, mass_props);

To support mass property computation for custom shapes, implement ComputeMassProperties2d or ComputeMassProperties3d for them.

Supported bevy_math Versions

bevy_math	bevy_heavy
0.17	0.3
0.16	0.2
0.15	0.1

License

bevy_heavy is free, open source, and permissively licensed! Except where noted (below and/or in individual files), all code in this repository is dual-licensed under either:

• MIT License (LICENSE-MIT or http://opensource.org/licenses/MIT)
• Apache License, Version 2.0 (LICENSE-APACHE or http://www.apache.org/licenses/LICENSE-2.0)

at your option. This dual-licensing approach is the de-facto standard in the Rust ecosystem, and there are very good reasons to include both.