Dds Files And Normalmaps

[Gildoran]

I was wondering if anybody knew much about compressing normalmaps into DDS files... I've heard DXT1 isn't very suitable for normalmaps and usually results in artifacts, so DXT5 should be used instead. I found instructions on how to use The Compressionator to compress normalmaps, but I can't get it to work. (it either crashes, or D3 can't load the resulting DDS file) I've used DXT1 to compress diffusemaps just fine, however. Has anybody managed to get DXT5 to work with normalmaps?

 

PS, does anybody know what RxGB means? Does it have to do with swizzling? (why is there an x between red and green?)

[Dram]

Screw that, I have a prog which is excellent for conversions. Have'nt had a problem with it

 

DDS Converter 2

 

I use it all the time for Orbiter textures.

 

You can select a lot of textures (like tgas or jpgs etc) and convert them all at once, so yeah. You can select whether it uses mipmaps or not etc.

[Gildoran]

Thank you for the suggestion; DDS Converter 2 seems less prone to crashes than the Compressionator. However it still doesn't seem to work for normalmaps. (D3 can read it just fine as a diffuse map, but can't seem to use it as a normalmap)

[New Horizon]

Thank you for the suggestion; DDS Converter 2 seems less prone to crashes than the Compressionator. However it still doesn't seem to work for normalmaps. (D3 can read it just fine as a diffuse map, but can't seem to use it as a normalmap)

Hmmm, that's odd. id used compressonator for their dds, did they use dxt5 for their normals? There must be something we're missing. I'll look into it when i get home.

[OrbWeaver]

http://www.modwiki.net/wiki/Texturing#Comp...nd_uncompressed

 

There is no advantage in using DXT5/3 if you don't have an alpha channel, these formats have no difference in how colour is stored (AFAIK).

 

RxGB should be used for normals, as DXT can lead to horrible blockiness that only shows up at an acute lighting angle (look at TDS for examples).

 

EDIT: according to kat's tutorial (http://www.quake3bits.com/htm/tutorials/create_dds_ati_compressonator.htm) it sounds like RxGB might actually be a form of DXT5 after all.

 

EDIT2: This does indeed seem to be the case, from http://www.lucasforums.com/showpost.php?p=...mp;postcount=31

 

RXGB is Doom3 style normalmap compression which is just DXT5 compression but with the red channel moved into the alpha channel and the red channel set to 0 . This gives better encoding fidelity for normalmaps provided you can unswizzle in the pixel shader (ie. texcol.r = texcol.a)

[Gildoran]

Ah, I had thought that RxGB was a form of DXT5. Anyway, has anybody managed to get RxGB or any other DDS format to work for normalmaps in D3? I have a 1024x1024 normalmap for a texture that I made, but it'd be too large unless compressed.

[New Horizon]

Ah, I had thought that RxGB was a form of DXT5. Anyway, has anybody managed to get RxGB or any other DDS format to work for normalmaps in D3? I have a 1024x1024 normalmap for a texture that I made, but it'd be too large unless compressed.

 

 

I still haven't had a chance to look into this myself. Have you dropped into Doom 3 world? They should be able to help, I'll also take a look at the prey demo. Prey seems to have chosen to go with dds over tga as well.