Exposing functions - e.g. running textureCompress for individual textures

[marwie]

Is your feature request related to a problem? Please describe.
I'd like to use existing compression functions for individual textures/primitives/...

Describe the solution you'd like
Similarly to #767 It would be nice to be able to run the textureCompress function on individual textures (providing the texture compression options per texture?)

Describe alternatives you've considered
Copying and modifying the code I need (e.g. the inner textures.map loop of textureCompress to apply webp compression to individual textures)

Additional context

glTF-Transform/packages/functions/src/texture-compress.ts

Line 107 in 32dc66e

textures.map(async (texture, textureIndex) => {

Something like this:
needle-tools@45fedf0
https://github.com/needle-tools/glTF-Transform/blob/45fedf070b0983e9de384893497780a2fbf2bb27/packages/functions/src/texture-compress.ts#L164

[donmccurdy]

Related:

• Add Pattern Function #845
• Can textureResize become textureCompress on the web? #801

I think we could do a textureCompress function, yes — would you be up for writing a PR?

It's worth noting that texture compression can be done in less code than I'm using, and @gltf-transform/functions will never expose the entirety of Sharp's API. So being able to do skip the wrapping function and use Sharp directly is something that I hope users will feel very free to do, too:

import sharp from 'sharp';
import { BufferUtils, HTTPUtils } from '@gltf-transform/core';

for (const texture of document.getRoot().listTextures()) {
  const buffer = await sharp(texture.getImage()).toFormat('webp', {lossless: true}).toBuffer();
  texture
    .setMimeType('image/webp')
    .setImage(BufferUtils.toView(buffer))
    .setURI(HTTPUtils.basename(texture.getURI()) + '.webp');
}

document.createExtension(EXTTextureWebP).setRequired(true);

[marwie]

Yes happy to PR this, just wanted to run some tests before to make sure I didnt break anything and it's working as intended.

Thanks for the code snippet. That's goo to know and maybe something I'll be doing then instead in our code and just handle the settings we ship in our extension (that being said having a fallback to the default gltf-transform compression function is still handy in cases where no explicit compression settings were assigned to a texture but we still want to apply defaults)

[donmccurdy]

Fixed by #859.