Small but complete C++ physics engine. It works as a standalone physics library that can be plugged into any project that needs simulation, this way it serves as a submodule of the game engine BulletEngine.

Until now it grew on its own, in a vacuum, though always with the game engine in mind. From here it grows alongside it, driven by what the engine turns out to need.

Features

• Bodies carry mass and inertia tensor, come as dynamic, kinematic or static, take forces and torques
• 6DOF carried through the whole solver, so every body moves and turns as freely as it is allowed to
• Constraints freeze position or rotation along chosen axes
• Colliders of box, sphere, cylinder and infinite ground, each holds a material, a layer and a mask
• Materials define friction and restitution
• Islands group bodies that touch and put them to sleep together
• Timer runs the simulation on a fixed step
• Queries cast rays and swept spheres through the world
• Continuous detection sweeps the path a fast body travels between steps
• Triggers report overlap without resolving it

Dependencies

Requires C++20 and has no external dependencies.

Structure

src/
├── collision/    shapes, materials, queries
├── dynamics/     world, bodies, solver
└── math/         vectors, matrices, quaternions

Someday

Infrastructure for plugging in modules, and the modules themselves:

• Joints
• Ragdolls
• Vehicles
• Destruction
• Ballistics