VGDS textures - potential problem?

Hi Arno et al -

I have had an interesting discussion from the AIG forums sent to me, that highlights a potential problem with textures that are missing alpha channels. The reason I've posted this here is because the VGDS models created by the Tweaker use one of two textures that are allegedly missing alpha channels!

One AIG mamber states:

"The DXT3 texture format must have an associated alpha, its how the format was designed.
What happens is that once an alpha-less DXT3 texture is displayed by the card the card tries to apply an alpha to it to display properly. This is quite hard work for the card, and once you get a few of these textures the card suddenly becomes overwhelmed and you get horrible stuttering while it tries to apply alpha's (sic) to all these alpha-less DXT3 textures.

So for once its not an FS issue - This will crop up regardless of the game you are playing. Its to do with the format and the display of it in the game engine by the card."

I believe there are two textures that have this problem in the VGDS models, one relating to the safedock and the other to the sasfegate model.

Unfortunately I wasn't given the texture names, and I'm not an AIG member, so I don't have access to the threads concerned. I just thought I'd flag this up since it affects probably a considerable number of sceneries that use thees VGDS.
 

arno

Administrator
Staff member
FSDevConf team
Resource contributor
Hi,

I just checked, but all of the textures as I included them with the VGDS Tweaker tool are DXT1. None of them as an alpha channel, so I would not use DXT3 for them in that case anyway.

I also do not understand the discussion about DXT3 without alpha channel completely. As far as I understand the format it would not be possible to make that.
 

n4gix

Resource contributor
In every case where I've created a DXT3 compressed bitmap using only a 24bit image, the resultant file had a "black Alpha" channel automatically generated...
 
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