# Objective
Give easy methods for uniform point sampling in a variety of primitive
shapes (particularly useful for circles and spheres) because in a lot of
cases its quite easy to get wrong (non-uniform).
## Solution
Added the `ShapeSample` trait to `bevy_math` and implemented it for
`Circle`, `Sphere`, `Rectangle`, `Cuboid`, `Cylinder`, `Capsule2d` and
`Capsule3d`. There are a few other shapes it would be reasonable to
implement for like `Triangle`, `Ellipse` and `Torus` but I'm not
immediately sure how these would be implemented (other than rejection
which could be the best method, and could be more performant than some
of the solutions in this pr I'm not sure). This exposes the
`sample_volume` and `sample_surface` methods to get both a random point
from its interior or its surface. EDIT: Renamed `sample_volume` to
`sample_interior` and `sample_surface` to `sample_boundary`
This brings in `rand` as a default optional dependency (without default
features), and the methods take `&mut impl Rng` which allows them to use
any random source implementing `RngCore`.
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## Changelog
### Added
Added the methods `sample_interior` and `sample_boundary` to a variety
of primitive shapes providing easy uniform point sampling.
948ea3137a