Module compound 

Baked compound collision shape.

Port of box3d-cpp-reference/src/compound.c and the compound group of include/box3d/types.h / collision.h.

Layout:

• types — CompoundDef/Data, child accessors, SurfaceMaterial consumers
• create — create/destroy with material/hull/mesh sharing
• serialize — convert to/from contiguous bytes
• cast — AABB, overlap, ray cast, shape cast
• query — AABB query, collide mover

Deferred: world shape attach. Compound CCD TOI lives in shape::toi (matching the live path in C shape.c; compound.c’s copy is #if 0).

SPDX-FileCopyrightText: 2025 Erin Catto SPDX-License-Identifier: MIT

Structs

ChildShape

Child shape of a compound. (b3ChildShape)

CompoundCapsule

A capsule that lives in a compound. (b3CompoundCapsule)

CompoundCapsuleDef

Definition for a capsule in a compound shape. (b3CompoundCapsuleDef)

CompoundData

The runtime data for a baked compound shape. (b3CompoundData)

CompoundDef

Definition for creating a compound shape. (b3CompoundDef)

CompoundHull

A hull that lives in a compound. (b3CompoundHull)

CompoundHullDef

Definition for a convex hull in a compound shape. (b3CompoundHullDef)

CompoundMesh

A mesh with non-uniform scale that lives in a compound. (b3CompoundMesh)

CompoundMeshDef

Definition for a triangle mesh in a compound shape. (b3CompoundMeshDef)

CompoundSphere

A sphere that lives in a compound. (b3CompoundSphere)

CompoundSphereDef

Definition for a sphere in a compound shape. (b3CompoundSphereDef)

Enums

ChildGeometry

Child geometry of a compound. (union half of b3ChildShape)

Constants

COMPOUND_VERSION

The compound version depends on the tree, mesh, and hull versions. (B3_COMPOUND_VERSION)

MAX_COMPOUND_MESH_MATERIALS

Meshes used in compounds have limited space for materials. (B3_MAX_COMPOUND_MESH_MATERIALS)

Functions

collide_mover_and_compound

Collide a capsule mover against a compound. (b3CollideMoverAndCompound)

compute_compound_aabb

Compute the AABB of a compound. (b3ComputeCompoundAABB)

convert_bytes_to_compound

Restore a compound from a byte buffer. (b3ConvertBytesToCompound)

convert_compound_to_bytes

Scrub and return the compound as a byte buffer. (b3ConvertCompoundToBytes)

create_compound

Create a baked compound shape. (b3CreateCompound)

destroy_compound

Destroy a compound shape. (b3DestroyCompound)

get_compound_capsule

Capsule at index. (b3GetCompoundCapsule)

get_compound_child

Child shape by flat index (capsules → hulls → meshes → spheres). (b3GetCompoundChild)

get_compound_hull

Hull at index. (b3GetCompoundHull)

get_compound_materials

Compound materials. (b3GetCompoundMaterials)

get_compound_mesh

Mesh at index. (b3GetCompoundMesh)

get_compound_sphere

Sphere at index. (b3GetCompoundSphere)

make_compound_child_sweep

Static compound-child sweep for TOI (child fixed in compound frame). xf = compoundTransform * childTransform. (b3MakeCompoundChildSweep)

overlap_compound

Test overlap between a compound and a shape proxy. (b3OverlapCompound)

query_compound

Query an AABB against compound children. (b3QueryCompound)

ray_cast_compound

Ray cast versus a compound. (b3RayCastCompound)

shape_cast_compound

Shape cast versus a compound. (b3ShapeCastCompound)