Normal map compression question

[demostenes]

Imagedds.py is converting NM into ATI2 DDS format. So normal map is 2x bigger than DXT5 albedo with same resolution (without alfa). It seems to me like waste of memory, is it slightly better quality really worthy 2x size? What was reasoning behind this? Or is there any hidden technical reason? I mean if I use dxt5 compression for NM and it will stay 3 channel, can I "break" something?

[silent]

Hi Jirka,

 

DXT5 is definitely not the right choice for normal compression - because you will loose precision in Red / Blue channels - and that will affect the lightning dramatically. You can just experiment with newly created project to get an idea what will be with the normalmap after DXT5 compression.

 

Using the ATI2 (BC5) will give you more detailed results: http://frustum.unigine.com/transfer/ati2_to_dxt5.gif

 

Thanks!

[demostenes]

Ok, thanks!