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Guest JoeW

VTP Textures - Friendly Warning

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I am sure that many of you already know this, but you need to be real careful with the chosen file format for VTP textures.I have spent a good part of the last 3 days fighting sporatic problems with my airport skirtings. The problem turned out to be with the texture file format, but it gave the appearence of a problem with the VTP code.I was using 8 bit 256x256 textures. I did this, because some of the Landclass textures are 8-bit normal bitmaps (at least they appeared to be, since they could be loaded into a standard graphics package).Unfortunately, I had eliminated the problem being with the textures, because the scenery would load correctly some times. However, when I added more textures to the BGL file, then the program would crash. Normally, if the texture format is incorrect, you would expect FS2002 to crash or not be display the texture at all.This was one heck of a frustrating battle, since I was off in the wrong direction the whole time (code not textures).I finally went with the Dx1 Opaque format, and things are working fine now.I am, however, curious about the 8-bit formats used by some of the Landclass textures. As I mentioned, these files are loaded as non-extended 8-bit bitmap formats, but they do not appear to be RGB or RLE encoded bitmaps (the file sizes are larger). If anybody knows the answer, I would like to hear it.Cheers,Allen

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By the way....I just downloaded Christian Stock's TMF manual. What a piece of work ! Thanks Christian.Allen

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I agree, we (NL2000 Team) came to the same conclusion while testing our new VTP scenery.Unless you use DXT texture you can get a crash while starting FS.Arno


Member Netherlands 2000 Scenery Team[a href=http://home.wanadoo.nl/arno.gerretsen]http://home.wanadoo.nl/arno.gerretsen/banner.jpg[/a]

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Hi Allen.8-bit is perfectly alright. But the textures must be mipped and flipped vertically. Alpha is allowed, and is the way to use transparency with VTP. 8-bit mipped & flipped.This is the format of CFS2 ground textures, and the format for FS2002 and CFS2 VTP line textures. It is the only way to get transparency with VTP.Dick

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But the textures must be mippedAhh...That explains the increased file size. I also did not know that you could have transparent VTP textures. I tried using transparent DX1 textures, but it did not work for VTP. That is good information to know.Allen

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Hi Dick,I might be making this much harder than it needs to be, but how do you add an alpha channel to an 8-bit image? Do you just add the channel in Photoshop and export the image as DXT1, or is there a more involved procedure? And if it's DXT1 only, then do you only get a 1-bit mask?thx,

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Hi Bill.I use PaintShopPro7, but the process should be the same. I save 32-bit alphaed images as PHOTOSHOP (*.psd), then open them with MS'Imagetool... from there I create the mips and save as 8-bit.You could also convert from DXT1 with alpha, or whatever from within Imagetool. The only thing Imagetool lacks is the ability to merge an alpha channel to an image... Elrond Elvish created such a tool with ... and that tool might be worth investigating.Martin Wright has [link:www.mnwright.btinternet.co.uk/programs/bmp2000.htm]Bitmap2000, which can load an 8-bit image, create an alpha ( transparency ) from a color ( save the pallete ), then call imagetool to mip to the 9 mips we need. It then can save as what he calls Extended format... 8-bit mipped with alpha.Imagetool can also be run in batch mode from a Dos Command window.The only odd part is really the flipping of the textures, required by VTP. I use XNView for that, as it allows a script to support batch processing of a whole folder at a time.Martin Wright also has DXTBmp, which includes a flipping function, but it cannot save as 8-bit... DXT1 non-nVidia works well, and can be then made 8-bit by imagetool.Dick

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Thanks, I'll give that a shot. I usually do things like the batch flipping in Photoshop where I can just write batch actions, so they'd be flipped before they got to ImageTool.

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Hi Bill.Just keep in mind that CUSTOM textures ( "252" or "253" ) must be flipped for VTP use, but the autogen isn't flipped.Dick

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Roger that. So do the textures, do the autogen in Annotator, then flip 'em and mip 'em. Got it.

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Just bear in mind that the DXT1 doesn't have a 'real' alpha channel, it's just black = alpha. So in photoshop (or whatever) just use black (for water) and white, but no greyscales. DXT3 uses a full 256 colour alpha channel, but that's not for terrain.There's a paragraph on that in my TMF manual.Cheers, Christian

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Yeah, that's what I meant in an earlier post by a 1-bit mask. I think Dick was saying that you could just make an 8-bit bmp with an alpha channel, however, and that does provide for a gradated mask. That will work, yes?

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And Just where might one find this " TMF Manual" ?Or am I comming in to late on this?Joe WatsonI just read a little farther on down and found it.ThanksJoe

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