Support KTX2 Texture Compression Format

[Lin Qin]

Hello,

Currently, most HTMLImageElement formats (e.g. JPEG / WebP / AVIF) focus on getting smaller size to download faster.

But video games (including WebGL) prefer texture compression formats which take much less memory (https://docs.unity3d.com/2020.3/Documentation/Manual/class-TextureImporterOverride.html).

Previously, the limitations of texture compression formats may:

    1. gpu raster is required;

    2. different platforms support different texture compression formats;

    3. some old formats (e.g. ETC2) are not smaller enough;

Now

    1. gpu raster is enabled by default;

    2. Basis Universal compression technology introduced in KTX2 can cross platform;

    3. ETC1S / ASTC can get smaller size.

         https://www.phoronix.com/scan.php?page=news_item&px=Khronox-KTX2-Format 

         https://github.com/ARM-software/astc-encoder/blob/main/Docs/FormatOverview.md#block-sizes

If HTMLImageElement supports texture compression formats, can reduce 75%~97% memory and some decoding time (or no decoding at all), then reduce power consumption.

The Khronos Group has published KTX-Software as open-source tools around dealing with KTX 2.0 compressed textures (https://github.com/KhronosGroup/KTX-Software).

I have tried integrating KTX-Software into chromium. It works well on Android.

So does it make sense to support KTX2 texture compression format?