Lightweight 3D physics engine for small games or prototyping

World world = create_world((WorldParams){ .gravity = {0, -9.81f, 0} });

Body floor = create_body(world, (BodyParams){ .mass = 0 }); // mass 0 = static
body_add_shape(world, floor, (ShapeParams){ .type = SHAPE_BOX, .box.half_extents = {10, 0.5, 10} });

Body ball = create_body(world, (BodyParams){ .mass = 1.0f, .position = {0, 5, 0} });
body_add_shape(world, ball, (ShapeParams){ .type = SHAPE_SPHERE, .sphere.radius = 0.5f });

while (running) {
    world_step(world, 1.0f / 60.0f);
    v3 pos = body_get_position(world, ball);
}
destroy_world(world);

• Pure C for strong perf and cross-platformness
• Really small API, nearly impossible to mess up
• Box/Sphere/Hull/Capsule/Mesh shape types
• Variety of common constraint/joints supported
• Unity build (todo: package as single-file-header script)

This is in early WIP state.

• Basic world step
• Add rigid bodies + shapes
• Discrete collision detection (no sweep/time of impact/continuous)
• Basic joints (rod/ball + socket)
• Barely working sleep + broadphase

• Incremental sub-island sleeping
• Mesh collisions
• Full suite of common constraint/joint implementations
• Swept physics step and collision detection
• Serialize/inspect tool (maybe remote visualizer??)
• Experiments! Different solvers, new constraint designs/formulations, new broadphase exploration, or CCD techniques

cmake -B build
cmake --build build
Requires SDL3 (fetched automatically) for the demo app. The physics engine itself has zero dependencies.

Nah. Public domain.