256 vs. 16 million colors

[Guest]

Hi Gerrish1/ You guessed right about why DXT3 is always exactly twice the size of DXT1. Each 4x4 DXT block takes up 8 bytes and DXT3 just adds another 8 bytes (16 x 4bits) to each block for the plain uncompressed Alpha.(btw - CFS3 supports DXT5 which adds yet another variation. 4 bit-interpolated Alpha. Same size as DXT3 but with a theoretical 8 bit Alpha data)2/3/ Unfortunately DXTBmp is a bit tied down by the fact it now relies on the nVidia codec to create DXT. This takes care of all the mip processing so it is a bit of a "black box". I feed in the fullsized data, it spits out a mipped DXT file using the parameters supplied.You have more control if you use the nVidia DDS plugin with PhotoShop. It would be possible (though a bit tedious) to do your designing in DDS and use my DDStoBMP utility to convert the final DDS image to FS format. The DDS plugin has a lot of extra options for fading the mips towards a destination colour and other things.The nVidia download also comes with 2 tools for splitting a DDS file into individual mip files and joining them together again. This would allow for seperate editing of each mip levelIt might also be possible (if I ever get some spare time...) to work out some sort of standalone "mip splitting" program myself that would do something similar (but in a more user-friendly way than the nVidia commandline tools).And of course ImageTool has options to seperate images out into their seperate mips. In theory these could be individually edited via DXTBmp as long as you used the "no mips" option when saving afterwards.I have a suspicion that FS2004 will probably follow CFS3 and switch over to DDS textures for most things. This would be a "good" thing in some ways. There is more direct support for DDS out there because it is a standard format. The FS variation on the DXT theme adds just enough different data to require specialised conversion tools.

[Guest]

Hi ChristianDXT is DirectX-specific only in the sense that, as far as I know, it was originally developed for DirectX. The internal structure of the DDS file is basically just a DirectDrawSurface structure (hence the name) and can be read straight in to DirectX programs without doing any processing at all.Now it is an Industry standard for Graphics Display. As Cards have evolved to support it in hardware the other systems like OpenGL have taken it on board.FS is a bit of a special case as regards loading textures. If you are flying over large areas then the sim is constantly reading-ahead and loading in terrain textures. If it were having to do a "on the fly" compression I suspect the overhead would be too much for many machines to provide smooth flying.