parry3d/mass_properties/
mass_properties_cuboid.rs

1use crate::mass_properties::MassProperties;
2use crate::math::{Point, PrincipalAngularInertia, Real, Vector};
3
4impl MassProperties {
5    pub(crate) fn cuboid_volume_unit_inertia(
6        half_extents: Vector<Real>,
7    ) -> (Real, PrincipalAngularInertia<Real>) {
8        #[cfg(feature = "dim2")]
9        {
10            let volume = half_extents.x * half_extents.y * 4.0;
11            let ix = (half_extents.x * half_extents.x) / 3.0;
12            let iy = (half_extents.y * half_extents.y) / 3.0;
13
14            (volume, ix + iy)
15        }
16
17        #[cfg(feature = "dim3")]
18        {
19            let volume = half_extents.x * half_extents.y * half_extents.z * 8.0;
20            let ix = (half_extents.x * half_extents.x) / 3.0;
21            let iy = (half_extents.y * half_extents.y) / 3.0;
22            let iz = (half_extents.z * half_extents.z) / 3.0;
23
24            (volume, Vector::new(iy + iz, ix + iz, ix + iy))
25        }
26    }
27
28    /// Computes the mass properties of a cuboid.
29    pub fn from_cuboid(density: Real, half_extents: Vector<Real>) -> Self {
30        let (vol, unit_i) = Self::cuboid_volume_unit_inertia(half_extents);
31        let mass = vol * density;
32        Self::new(Point::origin(), mass, unit_i * mass)
33    }
34}