use crate::mass_properties::MassProperties;
use crate::math::{Point, PrincipalAngularInertia, Real, Vector};
impl MassProperties {
pub(crate) fn cuboid_volume_unit_inertia(
half_extents: Vector<Real>,
) -> (Real, PrincipalAngularInertia<Real>) {
#[cfg(feature = "dim2")]
{
let volume = half_extents.x * half_extents.y * 4.0;
let ix = (half_extents.x * half_extents.x) / 3.0;
let iy = (half_extents.y * half_extents.y) / 3.0;
(volume, ix + iy)
}
#[cfg(feature = "dim3")]
{
let volume = half_extents.x * half_extents.y * half_extents.z * 8.0;
let ix = (half_extents.x * half_extents.x) / 3.0;
let iy = (half_extents.y * half_extents.y) / 3.0;
let iz = (half_extents.z * half_extents.z) / 3.0;
(volume, Vector::new(iy + iz, ix + iz, ix + iy))
}
}
pub fn from_cuboid(density: Real, half_extents: Vector<Real>) -> Self {
let (vol, unit_i) = Self::cuboid_volume_unit_inertia(half_extents);
let mass = vol * density;
Self::new(Point::origin(), mass, unit_i * mass)
}
}