This repo contains the source for a physics library. The simulation uses the method of eXtended Position Based Dynamics (XPBD) which works on positions directly which allows for real-time simulation. Accuracy is achieved by substepping (splitting a physics steps into many smaller steps). The API allows users to create worlds and add entities to these worlds. A world can be stepped forward, queried and modified.
A collection of demos can be found online at https://patricklbell.github.io/xpbd/. The source
for each demo, located under each folder src/demos/*, acts as an informal documentation.
- Rigid bodies with discrete collision detection (with non-tunnelling guarantees)
- Sphere
- Concave polytope
- Constraints with substep independent compliance
- Distance (eg. fixed, unilateral, offset)
- Hinge
- Swing
- Twist
- Lock orientations
- Linear DOF (eg. prismatic)
- Softbodies (eg. soft ball or cloth)
- Particle body with hashgrid collision detection
- Edge distance constraints
- Tetrahedral volume constraints
- Internal pressure constraint
- Self-collision
- Collision with rigid bodies
- Raycasting
- Kinematic bodies
- Static and dynamic friction
- Linux x86/x64/ARM32/ARM64
- WebAssembly (but there are no bindings)
No special CPU instructions are required.
The build is managed through the build.sh script, refer to the help message for usage instructions.
- Cross-compiles as C and C++
- gcc/g++/clang/clang++ recent enough to support C11
- Library only depends on libc and libm
The graphics run on both Wayland and X11 and requires
X11 development libraries and support for EGL. Following the dependencies on
this page should cover all the dependencies.
For reference, the build links X11 and Xext.
The demos can be built for web by installing Emscripten and adding it to your path.
Support for profiling with Tracy can be included by adding --trace. A submodule is
included in the repo under src/third_party/tracy which needs to be
initialised and is where you can build the profiling tools. Profiling
requires a C++ compiler.