Struct DistanceConstraint 

pub struct DistanceConstraint {
    pub body_a: BodyHandle,
    pub body_b: BodyHandle,
    pub anchor_a: Vec2,
    pub anchor_b: Vec2,
    pub rest_length: f32,
    pub compliance: f32,
    /* private fields */
}

Maintain a fixed distance between two local anchor points on two bodies. With compliance = 0 this is a rigid rod; compliance > 0 gives spring behavior.

Fields

body_a: BodyHandle

body_b: BodyHandle

anchor_a: Vec2

anchor_b: Vec2

rest_length: f32

compliance: f32

0.0 = rigid rod, >0 = soft spring (XPBD compliance).

Implementations

impl DistanceConstraint

pub fn new( body_a: BodyHandle, anchor_a: Vec2, body_b: BodyHandle, anchor_b: Vec2, rest_length: f32, ) -> Self

pub fn rigid_rod( body_a: BodyHandle, anchor_a: Vec2, body_b: BodyHandle, anchor_b: Vec2, rest_length: f32, ) -> Self

Create a rigid rod (exact distance, zero compliance).

pub fn soft( body_a: BodyHandle, anchor_a: Vec2, body_b: BodyHandle, anchor_b: Vec2, rest_length: f32, compliance: f32, ) -> Self

Create a soft spring (positive compliance = 1/k).

pub fn with_compliance(self, c: f32) -> Self

Trait Implementations

impl Clone for DistanceConstraint

fn clone(&self) -> DistanceConstraint

Returns a duplicate of the value.

fn clone_from(&mut self, source: &Self)

Performs copy-assignment from source.

impl Constraint for DistanceConstraint

fn compute_cdot(&self, bodies: &HashMap<BodyHandle, BodyState>) -> f32

Compute the velocity constraint violation (Cdot = J * v).

fn compute_c(&self, bodies: &HashMap<BodyHandle, BodyState>) -> f32

Compute the position constraint violation (C).

fn get_compliance(&self) -> f32

XPBD compliance (inverse stiffness). 0 = rigid.

fn effective_mass(&self, bodies: &HashMap<BodyHandle, BodyState>) -> f32

Compute effective constraint mass (1 / (J M^-1 J^T)).

fn apply_impulse( &self, bodies: &mut HashMap<BodyHandle, BodyState>, lambda: f32, )

Apply the corrective impulse to body states.

fn accumulated_impulse(&self) -> f32

Accumulated impulse for warm starting.

fn reset_accumulated(&mut self)

fn add_accumulated(&mut self, d: f32)

fn body_handles(&self) -> Vec<BodyHandle>

Bodies involved in this constraint.

fn bias(&self, bodies: &HashMap<BodyHandle, BodyState>, dt: f32) -> f32

Baumgarte position bias.

fn prepare(&mut self, _bodies: &HashMap<BodyHandle, BodyState>, _dt: f32)

Prepare the constraint for the current step (pre-compute cached values).

fn solve_velocity( &mut self, bodies: &mut HashMap<BodyHandle, BodyState>, dt: f32, )

Solve velocity constraint (one iteration).

fn solve_position( &mut self, bodies: &mut HashMap<BodyHandle, BodyState>, dt: f32, )

Solve position constraint using XPBD (one sub-step).

fn impulse_bounds(&self) -> (f32, f32)

Whether this constraint has an upper/lower impulse clamp.

impl Debug for DistanceConstraint

fn fmt(&self, f: &mut Formatter<'_>) -> Result

Formats the value using the given formatter.