Compressed texture cannot be displayed

[秦时明月]

The detection of compressed texture cannot be displayed on the page.
For example, this page uses ktx texture:
https://threejs.org/examples/webgl_loader_texture_ktx.html

[sebavan]

We can not read them easily and it would require to interject a special render pass to copy them into another texture which is to risky as it would change a lot of states in the context.