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Egbert Drenth

BMP to DXT3...

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Hi,I have converted some aircraft texture bitmaps from BMP to DXT3 format.I wondered if I can do this to any bmp file, thus also textures files of sceneries etc.I know I will loose some crispiness but that is no problem.Does anyone else has already converted all his/her bmp's to DXT3?Are There any no-no's?

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yes and no. First, the basics. (btw, dont do this unless you know exactly how FS9 works...so you can repair it if break anything. And always make backups before messing with files).32bit BMP files allows for smooth colors and gradients. However, they are huge (usually about 4megs in size in FS9). DXT3s are compressed, but it gets rid of a lot of color/gradient info. So a smooth black to white gradient will have "banding" when converted to DXT3. The benefit is of course a much small file.AIRCRAFT:Textures - You can convert almost all, but i don't recommend converting the following:Panels - don't convert the BMP files found in your panel's folder. You will see them show up black if you do. I actually dont use any 2D panels, so i've deleted all the BMPs and commented out the file=*.bmp from the panel config. You can still pull up the 2D window, but it'll be missing the bmp background...however, since i only use it to turn on a switch, it doesnt bother me. The rest of the 99% time im in the VC. (but dont do this if you fly a lot of heavies....keep those BMPs around).Props - Any props converted will have a terrible result. You will see heavy banding. Thus, leave any prop textures as 32bit BMPsGlass/Reflections - Most are okay to convert, but some will leave you with heavy banding and ugliness. You can always make a backup and experiment. If the file is small, then it's best to leave it be.Super Smooth Glossy Paints - If you convert these, you will likely see banding on the texture. For example, the bare-metal paint on American Airlines. However, experiment with it by making backups.Lighting - Most lighting BMPs have a "L" in their name, such as Wings_L.bmp. These BMPs contain a smooth alpha layer which is the light's opacity. If you convert these, the smooth light will have banding. However, you probably won't notice it much.DXT1 - i've converted all my AI plane's textures to DXT1. Since i dont stare at AI all day, i dont see much of a difference from a distance (or even close up).TERRAIN/SCENERY/CLOUDS:I highly recommend you to NOT convert scenery BMPs. Yes you can convert most, however, you will notice some weird graphics. For example, the runways can appear completely black, or trees loose their transparency, etc. This is because many scenery BMPs use a lot of alpha masking. By converting, some alpha layers loose certain information, which makes them no longer transparent. FS9's ROOT Files:Don't convert stuff in your root Texture folder. There are sky/water/cloud BMPs in there, which will loose their alphas if converted (you will see black squares all over the sky).so yeah, convert planes, not scenery. -feng

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Egbert,if you do convert to DXT3, use DXTBmp. In my experience, DXTBmp does a much better job than Imagetool. Try to convert a texture with a gradual transition between two colours with both programs and you will see what I mean. Regards,Jure

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Hi Feng & Jure,Thanks a lot for your replies!You have saved me a lot of work (and aggravation afterwards) because I planned to convert my scenery and default texture files, but this seems not to be a good idea.

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Egbert,the key with converting textures is to be careful with transparencies. If you have a 32-bit bmp with alpha channel, be sure to convert it to DXT3 with alpha channel and so forth. 24-bit bmp's can usually be converted to DXT1 safely. Just like Feng said, make backup first and experiment. I did convert quite a few scenery textures, mostly add-on airports - some of them have huge 1024x1024 ground textures which eat a lot of memory if in 32-bit. Sometimes it doesn't work, sometimes it works...Same with clouds, have my main cloud file in DXT3 (the name escapes me right now, but FE will do that for you if you have it) One more thing to consider are mip maps. If you save (scenery) textures with mip maps, there won't be as much shimmering - but it can lead to stutters. Be careful here. I often mip map textures with lots of patterns, like buildings with lots of windows, fences and such. I would advice strongly against mip-mapping aircraft textures. Yours and AI's alike. This is valid for nVidia graphic cards at least. :)Regards,Jure

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