nphysics

nphysics is a 2 and 3-dimensional physics engine for games and animations. It uses ncollide for collision detection, and nalgebra for vector/matrix math.

Its most distinctive feature is its genericity wrt the simulation dimension. That means you can use it for both 2-dimensional physics and 3-dimensional physics. Higher dimensions could be possible, but nphysics has not be written/tested with those in thought.

Examples are available on the examples directory. There is also a short (outdated) demonstration video.

An on-line version of this documentation is available here.

Why another physics engine?

There are a lot of physics engine out there. However having a physics engine written in rust is much more fun than writing bindings and has several advantages:

• it shows that rust is suitable for soft real-time applications
• it shows how well rust behaves with highly generic code
• it shows that there is no need to write two separate engine for 2d and 3d: genericity wrt the dimension is possible (modulo low level arithmetic specializations for each dimension).
• in a not-that-near future, C++ will die of ugliness. Then, people will search for a physics engine and nphysics will be there, proudly exhibiting its rusty sexyness.

Compilation

You will need the last nightly build of the rust compiler and the official package manager: cargo.

Simply add the following to your Cargo.toml file if you want the 3d version of nphysics, using 32-bits foalting point numbers:

[dependencies.nphysics3df32] git = "https://github.com/sebcrozet/nphysics"

Depending on the accuracy or the dimension that you need, nphysics3df32 may be replaced by:

• nphysics2df32 − for 2d collision detection and 32 bits precision.
• nphysics3df32 − for 3d collision detection and 32 bits precision.
• nphysics2df64 − for 2d collision detection and 64 bits precision.
• nphysics3df64 − for 3d collision detection and 64 bits precision.

Use make examples to build the demos and execute ./your_favorite_example_here --help to see all the cool stuffs you can do.

Features

• static and dynamic rigid bodies
• common convex primitives: cone, box, ball, cylinder
• concave geometries build from convex primitives (aka. compound geometries)
• stable stacking
• island based sleeping (objects deactivation)
• ray casting
• swept sphere based continuous collision detection
• ball-in-socket joint
• fixed joint

What is missing?

nphysics is a very young library and needs to learn a lot of things to become a grown up. Many missing features are because of missing features on ncollide. Features missing from nphysics itself include:

• kinematic bodies
• efficient signaling system
• more joints, joint limits, joint motors and breakable joints.
• soft-bodies (see https://github.com/natal/roft for a draft)
• parallel pipeline
• GPU-based pipeline

Dependencies

All dependencies are automatically cloned with a recursive clone. The libraries needed to compile the physics engine are:

• ncollide: the collision detection library.
• nalgebra: the linear algebra library.

The libraries needed to compile the examples are:

• kiss3d: the 3d graphics engine.
• rust-sfml: the 2d graphics engine.