function onResourceLoaded(res) {
	delete failureLoadedAssets[res.src];
	// increment the loading counter
	loadCount++;

	// currrent progress
	const progress = loadCount / resourceCount;

	// call callback if defined
	if (typeof onProgress === "function") {
		// pass the load progress in percent, as parameter
		onProgress(progress, res);
	}
	eventEmitter.emit(LOADER_PROGRESS, progress, res);
}
just increment the number of already loaded resources
@ignore