index.ts

import { 
  Assets,
  extensions,
} from 'pixi.js'
import { TauriFilesystemLoader } from './TauriFilesystemLoader'

extensions.add(TauriFilesystemLoader)

// Loads normally using the HTTP adapter
Assets.load('https://pixijs.com/bunny.png')

// Loads the file with the TauriFilesystemLoader since the path starts with `/fs`
Assets.load('/fs/images/bunny.png')

TauriFilesystemLoader.ts

// Module imports
import {
	ExtensionType,
	type LoaderParser,
	LoaderParserPriority,
} from 'pixi.js'
import { 
	BaseDirectory,
	exists,
	readFile,
	readTextFile,
} from '@tauri-apps/plugin-fs'

const EXTENSION_NAME = 'TauriFilesystemLoader'

export function TauriFilesystemLoader(): LoaderParser {
	return {
		name: EXTENSION_NAME,

		extension: {
			name: EXTENSION_NAME,
			priority: LoaderParserPriority.High,
			type: ExtensionType.LoadParser,
		},

		/** Handle loading the asset if it uses the `/fs` root path. */
		test(url: string) {
			return /^\/fs/iu.test(url)
		},

		/** Load the file. */
		async load(url: string) {
			const readOptions = { baseDir: BaseDirectory.Resources }
			const filePath = url.replace(/^\/fs/iu, '')

			// Throw if the file doesn't exist
			if (!exists(filePath, readOptions)) {
				throw new Error(`File ${filePath} does not exist.`)
			}

			// Load text content files as strings.
			if (/\.(json|txt)$/.test(filePath)) {
				return readTextFile(filePath, readOptions)
			}

			// Assume it's a binary file.
			return readFile(filePath, readOptions)
		},
	}
}