ASTC single channel format support.

General Feedback & Requests
1

It would be really beneficial to support single channel compression for ASTC. On DX11 we can use BC4 for multiple things like ao, roughness, metalness, alpha, masks and even for stationary shadowmaps(area shadows don’t mind compression artefacts that much)
This would save lot of package size, memory and bandwith. With quality settings of 3 this format compression ratio is 0.445. With quality settings of 2 compression ratio is 0.33375.
ASTC support various texture formats so there really isn’t any reasons not to support single channel format.
https://www.khronos.org/opengl/wiki/ASTC_Texture_Compression

Shadowmap compression PR. https://github.com/EpicGames/UnrealEngine/pull/3746

2

No one has any opinions?

3

Well, for what it’s worth I too think that this would be very useful addition to the engine. It’s also a shame that your shadowmap compression PR got rejected.