I'm struggling to read meaningful values from an image asset's Image.getPixels() method on the WebGL platform - everything is just set to 0,0,0,0;

The very first line of WebGLImage.getPixels() is
if (frameBuffer == null) return null;
so clearly the frameBuffer has to be set first - this only seems to happen in createTexture() when renderTarget is set to true, and renderTarget is not set to true for preloaded Assets.

Even so, I set renderTarget to true ( I had to change it's access to public ), called createTexure(), then getPixels(), but I still get an array of complete zeros.

Any clues as to how to read the pixles from an image asset?
Jake

For non-rendertargets use the at function instead (we should probably unify that). But for that to work, the images have be be loaded with the readable option. When your assets are defined in your khafile you can just add that option in there ala project.addAssets("Whatever/**", { readable: true }); and if you load your images manually readable is a parameter of Assets.loadImageFromPath. Ideally you only use readable for images which really need it because it doubles RAM usage (images have to be kept in GPU mem for rendering and in CPU mem for direct access).

Ah, thanks for this.
Strangely I did not have to set the readable attribute to true at all - the pixels were already available in the asset image without doing so. Perhaps it is because I'm reading the pixel values directly upon loading, prior to using it as a texture in a 3D scene, so it is still stored as a html Image.
Regards, Jake

The html5 backend is less aggressive in throwing out unnecessary data but that might change so be careful. It won't work at all in any of the native backends without readable set to true.