[glTF] Load buffers and images in parallel

[dmnsgn]

As convenient as it is, a for-of loop will run sequentially. Need to use:

   await Promise.all(images.map(async (image) => {
    await loadImage(image)
   // ...
  }));

pex-renderer/loaders/glTF.js

Lines 916 to 942 in ed823d4

	for (let image of json.images) {
	// https://github.com/KhronosGroup/glTF/blob/master/specification/2.0/README.md#uris
	if (isBinary || image.bufferView) {
	const bufferView = json.bufferViews[image.bufferView]
	bufferView.byteOffset = bufferView.byteOffset || 0
	const buffer = json.buffers[bufferView.buffer]
	const data = buffer._data.slice(
	bufferView.byteOffset,
	bufferView.byteOffset + bufferView.byteLength
	)
	const blob = new Blob([data], { type: image.mimeType })
	const uri = URL.createObjectURL(blob)
	image._img = await loadImage({ url: uri, crossOrigin: 'anonymous' })
	} else if (isBase64(image.uri)) {
	image._img = await loadImage({
	url: image.uri,
	crossOrigin: 'anonymous'
	})
	} else {
	// TODO why are we replacing uri encoded spaces?
	image._img = await loadImage({
	url: [basePath, image.uri].join('/').replace(/%/g, '%25'),
	crossOrigin: 'anonymous'
	})
	}
	}
	}

pex-renderer/loaders/glTF.js

Lines 882 to 892 in ed823d4

	for (let buffer of json.buffers) {
	if (isBinary) {
	buffer._data = bin
	} else {
	if (isBase64(buffer.uri)) {
	buffer._data = decodeBase64(buffer.uri)
	} else {
	buffer._data = await loadBinary([basePath, buffer.uri].join('/'))
	}
	}
	}

[vorg]

Revisit when refactoring glt loader. Pushed to v5