model-cache

An optionally asynchronous class for cache object instances including three.js objects so they can be retrieved without duplicating the objects.

!> Note that geometry and material instances are not cloned by default so they should be changed before modifying.

Use

Caching async model loads

Creates a copy of the model when the asynchronous load resolves.

import { ModelCache } from '@gov.nasa.jpl.honeycomb/model-cache';

const cache = new ModelCache();

async function getModel(url) {
    if (cache.has(url)) {
        return cache.getClone(url);
    } else {
        const modelPromise = new Promise(resolve => loader.load(res => resolve(res.scene)));
        cache.add(url, modelPromise);
        return modelPromise;
    }
}

Caching created models

import { ModelCache, hash } from '@gov.nasa.jpl.honeycomb/model-cache';

const cache = new ModelCache();

function createArc(length, angle) {
    const str = hash(length, angle);
    if (cache.has(str)) {
        return cache.getClone(str);
    } else {
        const arc = new LineArc(length, angle);
        cache.add(str, arc);
        return arc;
    }
}

API

Functions

hash

hash( args : ...any ) : String

Converts the given objects into a hash.

ModelCache

Cache for three.js models and objects

add

add( hash : String, model : Object | Promise<Object> ) : void

Adds the given object to the cache indexed by hash.

has

has( hash : String ) : Boolean

Returns whether or not the given hash exists in the cache.

isPending

isPending( hash : String ) : Boolean

Returns whether the object indexed by the given hash is pending a promise that hasn't resolved yet.

delete

delete( hash : String ) : Object | Promise<Object>

Removes the object at the given hash and returns the deleted object.

get

get( hash : String ) : Object | Promise<Object>

Returns the original object added into the cache.

getClone

getClone( hash : String ) : Object | Promise<Object>

Returns a clone of the object indexed by the given hash or a promise that will resolve with a copy.

markUnused

markUnused(  ) : void

Increments the amount of times a model has been left unused by one. If a model has never been marked unused then it is set to 1. Every time a model is retrieved using getClone the unused counter is reset.

cullUnused

cullUnused( unusedCount : Number = 1 ) : void

Removes any cached item that has been marked as unused >= count number of times. The number of models removed is returned.

clear

clear(  ) : void

Clears the cache entirely. The number of models removed is returned.