Why KSP 1.8 only supports .DDS DXT5?

[FreeThinker]

Question: Are there any inherent advantages in using .DDS DXT5?

Edited October 30, 2019 by FreeThinker

[Electrocutor]

1 hour ago, FreeThinker said:

Question: Are there any inherent advantages in using .DDS DXT5?

https://docs.unity3d.com/Manual/class-TextureImporterOverride.html

Quote

While Unity supports many common image formats as source files for importing your Textures
 (such as JPG, PNG, PSD and TGA), these formats are not used during realtime rendering
 by 3D graphics hardware such as a graphics card or mobile device. 3D graphics hardware requires Textures to be compressed in specialized formats which are optimised for fast Texture sampling. The various different platforms and devices available each have their own different proprietary formats.

 

[Manwith Noname]

I thought this was due to the Unity upgrade (as in Unity no longer supports certain formats rather than Squad taking it out of KSP) but it does support more than DXT5 (BC3). It's worth noting, the RGB colour space across DXT1(BC1), 3(BC2) and 5(BC3) is the same. What changes is how alpha channels are handled. In this sense, DXT5 offer the "best" compression method for the alpha channel out of those 3. If you don't need information in the alpha (typically specular data), then you can still use DXT1.

I imagine it has got to the point where not many people use DXT3 for the small amount of memory saving and instead just use DXT5 anyway. Also, maybe BC7 is supported now?