Struct FixedJoint 

pub struct FixedJoint<const D: usize> {
    pub body_a: BodyHandle,
    pub body_b: BodyHandle,
    pub anchor_a: SVector<f64, D>,
    pub anchor_b: SVector<f64, D>,
    pub stiffness: f64,
}

Fixed joint: locks two bodies at a fixed relative position.

The joint maintains the initial relative offset anchor_b - anchor_a (in world space at the time of creation). All translational DOF are removed.

Fields

body_a: BodyHandle

body_b: BodyHandle

anchor_a: SVector<f64, D>

Local-space anchor on body A.

anchor_b: SVector<f64, D>

Local-space anchor on body B.

stiffness: f64

Constraint stiffness [0, 1]. 1.0 = rigid, <1.0 = allows some drift.

Implementations

impl<const D: usize> FixedJoint<D>

pub fn new(body_a: BodyHandle, body_b: BodyHandle) -> Self

Create a fixed joint connecting body A and body B at their current positions. The anchors default to the body origins.

pub fn with_anchors( body_a: BodyHandle, body_b: BodyHandle, anchor_a: SVector<f64, D>, anchor_b: SVector<f64, D>, ) -> Self

Create with specific local-space anchors.

Trait Implementations

impl<const D: usize> Constraint<D> for FixedJoint<D>

fn bodies(&self) -> (BodyHandle, BodyHandle)

The two bodies this constraint connects.

fn as_any(&self) -> &dyn Any

Cast to std::any::Any for downcasting in tests/lab.

fn as_any_mut(&mut self) -> &mut dyn Any

Cast to std::any::Any for downcasting in tests/lab.

fn solve(&self, body_a: &mut RigidBody<D>, body_b: &mut RigidBody<D>, _dt: f64)

Solve the constraint by applying positional corrections. Called multiple times per frame for iterative convergence.

fn solve_velocity( &self, body_a: &mut RigidBody<D>, body_b: &mut RigidBody<D>, _dt: f64, _callback: Option<&mut dyn PhysicsCallback<D>>, )

Optional velocity-level correction (impulse-based, Fix 7). Called after position solve for hybrid PBD+impulse dynamics. Default: no-op (pure PBD).