Struct ContactCache 

pub struct ContactCache { /* private fields */ }

Per-step contact impulses, keyed by feature, for warm starting.

Usage is two calls per step around the solve: ContactCache::warm_start before it to build the seed vector, ContactCache::store after it to record the result. store replaces the whole table rather than merging, so contacts that ended are dropped and the cache cannot grow without bound.

Implementations

impl ContactCache

pub const DEFAULT_CELL: f64 = 2e-3

Default quantization cell, in metres.

Coarse enough to absorb the sub-millimetre wander of a narrow-phase contact point on a resting face, fine enough to keep the corners of a centimetre-scale box distinct.

pub fn new(cell: f64) -> Self

Create a cache with a given quantization cell size, in metres.

pub fn key(&self, state: &State, c: &Collision) -> ContactKey

The feature key for one contact at the current state.

pub fn warm_start(&mut self, state: &State, contacts: &[Collision]) -> Vec<Vec3>

Seed impulses for contacts, in the same order, from the previous step.

Contacts with no cached match seed at zero, which is exactly the cold start. The returned vector is what crate::solve_contacts_warm takes.

pub fn store( &mut self, state: &State, contacts: &[Collision], impulses: &[Vec3], )

Record the solved impulses for the next step’s warm start.

pub fn clear(&mut self)

Forget every cached contact. Call after teleporting or resetting a state, where last step’s impulses are not a guess about this step.

pub fn stats(&self) -> (usize, usize)

(hits, misses) since construction or the last Self::clear.

A persistently low hit rate on a body that is visibly resting means the key is not identifying the feature — the cell size is likely wrong for the scale of the model.

pub fn len(&self) -> usize

Number of contacts currently remembered.

pub fn is_empty(&self) -> bool

Whether anything is remembered.

Trait Implementations

impl Clone for ContactCache

fn clone(&self) -> ContactCache

Returns a duplicate of the value.

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

Performs copy-assignment from source.

impl Debug for ContactCache

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

Formats the value using the given formatter.

impl Default for ContactCache

fn default() -> Self

Returns the “default value” for a type.