EXTTextureWebP

EXT_texture_webp enables WebP images for any material texture.

WebP offers greatly reduced transmission size, but requires browser support. Like PNG and JPEG, a WebP image is fully decompressed when uploaded to the GPU, which increases upload time and GPU memory cost. For seamless uploads and minimal GPU memory cost, it is necessary to use a GPU texture format like Basis Universal, with the KHR_texture_basisu extension.

Defining no ExtensionProperty types, this Extension is simply attached to the Document, and affects the entire Document by allowing use of the image/webp MIME type and passing WebP image data to the Texture.setImage method. Without the Extension, the same MIME types and image data would yield an invalid glTF document, under the stricter core glTF specification.

Properties:

• N/A

Example

import { EXTTextureWebP } from '@gltf-transform/extensions';

// Create an Extension attached to the Document.
const webpExtension = document.createExtension(EXTTextureWebP)
    .setRequired(true);
document.createTexture('MyWebPTexture')
    .setMimeType('image/webp')
    .setImage(fs.readFileSync('my-texture.webp'));

WebP conversion is not done automatically when adding the extension as shown above — you must convert the image data first, then pass the .webp payload to Texture.setImage.

When the EXT_texture_webp extension is added to a file by glTF-Transform, the extension should always be required. This tool does not support writing assets that "fall back" to optional PNG or JPEG image data.