rigid_body_locking_translations_rotations

It is sometimes useful to prevent a rigid-body from rotating or translating. One typical use-case for locking rotations is to prevent a player modeled as a dynamic rigid-body from tilting. These kind of degree-of-freedom restrictions could be achieved by joints, but locking translations/rotations of a single rigid-body wrt. the cartesian coordinate axes can be done in a much more efficient and numerically stable way. That's why rigid-bodies have dedicated methods for this.

Example 2D

/* Lock translations/rotations when the rigid-body is created. */
let rigidBodyDesc = RAPIER.RigidBodyDesc.dynamic()
    .lockTranslations() // prevent translations along along all axes.
    .lockRotations();   // prevent rotations.
let rigidBody = world.createRigidBody(rigidBodyDesc);

/* Lock translations/rotations after the rigid-body creation. */
// The last `true` argument makes sure the rigid-body is awake.
rigidBody.lockTranslations(true, true);
rigidBody.lockRotations(true, true);

Example 3D

/* Lock translations/rotations when the rigid-body is created. */
let rigidBodyDesc = RAPIER.RigidBodyDesc.dynamic()
    .lockTranslations() // prevent translations along along all axes.
    .lockRotations()   // prevent rotations along all axes.
    .enabledRotations(true, false, false); // only enable rotations along the X axis.
let rigidBody = world.createRigidBody(rigidBodyDesc);

/* Lock translations/rotations after the rigid-body creation. */
// The last `true` argument makes sure the rigid-body is awake.
rigidBody.lockTranslations(true, true);
rigidBody.lockRotations(true, true);
rigidBody.setEnabledRotations(true, false, false, true);