N16: Add Rapier and Salva (#400)

Author: sebcrozet

content/posts/newsletter-016/index.md

@@ -534,6 +534,63 @@ in 0.11.0.
 
 [glam]: https://github.com/bitshifter/glam-rs
 
+### [Rapier]
+
+[![Rapier logo](rapier-logo.svg)][Rapier]
+
+[Rapier] is a set of 2D and 3D physics engines for games, animation and
+robotics written in Rust.
+
+[This month][rapier-november] the version 0.4.0 has been released with
+exciting new features:
+
+- the ability to read contact and proximity information from the narrow-phase.
+- the ability to lock some translations and/or rotations for a rigid-body
+  without using joints.
+
+The following demo shows examples of translation locking (on the blue cuboid)
+and rotation locking (full locking on the capsule, partial locking on the
+cuboid):
+
+![Rapier features](rapier-demo.gif)
+
+A cross-platform determinism bug appearing on MacOS with the new Apple M1
+ARM processor has also been fixed.
+
+The [bevy_rapier] plugin for the Bevy game engine has been updated to support
+all the aforementioned features. In addition, it supports:
+
+- the automatic removal of rigid-bodies, colliders, and joints when the entity
+  they are attached to are removed from the Bevy ECS.
+- the ability to attach multiple colliders to a single rigid-body using Bevy
+  Hierarchy.
+
+[Rapier]: https://rapier.rs
+[rapier-november]: https://www.dimforge.com/blog/2020/12/01/this-month-in-dimforge/
+[bevy_rapier]: https://www.rapier.rs/docs/user_guides/rust_bevy_plugin/getting_started
+
+### [Salva]
+
+[![Salva logo](salva-logo.svg)][Salva]
+
+[Salva] is a set of 2D and 3D particle-based fluids simulation engines for
+games and animation written in Rust.
+
+Starting [this month][salva-november] Salva 0.5.0 no longer supports
+[nphysics] for simulating rigid-bodies. Instead, it implements two-ways
+coupling with [Rapier] (see the
+[demo](https://twitter.com/dimforge/status/1329467380158898183)).
+
+In addition to the Rapier integration, it is now possible to query Salva
+to retrieve all the fluid particles located inside an AABB. This can be
+useful for, e.g., spawning new particles ensuring there isn't anything
+there already.
+
+[Salva]: https://salva.rs
+[salva-november]: https://www.dimforge.com/blog/2020/12/01/this-month-in-dimforge/
+[salva-demo]: https://twitter.com/dimforge/status/1329467380158898183
+[nphysics]: https://nphysics.org
+
 ### [rib]
 
 ![rib](rib.gif)