Photoreal mipmapping

[Guest JohnC]

I am mystified about still another aspect of my photoreal scenery, made using Terrabuilder which uses FS Texture Converter. Why do the mip mapping rules seem to change for ground textures that are made with alpha masks to create real water? If I make two separate side by side sceneries, the ground textures made using alpha masks have a clearly coarser texture than the adjoining textures compiled without the alpha mask. So I can only suspect the mipmapping rules use a lower size texture when alpha masks are present. Can anyone suggest a fix?

[arno 1]

Hi,I have never seen something like that and I don't think the alpha channel should have an influence like that. But could it maybe be that they use different texture formats (DXT1 for the non-alpha ones and DXT3 for the alpha ones)? DXT3 textures are bigger (twice the size of a DXT1). I always thought this was due to the increased alpha channel, but maybe there are more differences.

[bob.bernstein 0]

I noticed that the fstexture converter does produce a bit of "different" appearance when there is an alpha channel included and combined using that converter. You might try to load the offending textures into imagetool and re-outputthem from imagetool. That made a nice difference for me.Bob

[Guest JohnC]

Thanks for the reply, guys...The FSTexture Converter by Elrond Elvish had a seting using DXT1 with alpha "FS2k2 method. I will continue to experiment, but this method produces very nice results without an alpha mask so I am not sure what is going on here. I did notice the same degradation with an all white alpha mask which produces no "water" at all, thinking that perhaps FS9 triggered a coarser bitmap when water needed to be displayed, but the coarse images were still there. More later.PS Arno, all my textures are 43kb.

[GHD 21]

If they are 43Kb, they must be DXT1 with alpha and mipmaps. I see no degradation with or without alpha.George

[bob.bernstein 0]

do this simple experiment.Take one of the "odd looking" dxt1 with alpha textures from Elrond's utility.open it in ms imagetoolsave it out as a 32bit tga file or bmp.Then open it again in imagetool, and save it out as dxt1 +alpha.Tell me if you see a difference now in the appearance.

[Guest JohnC]

I took a texture. opened it in imagetool,saved it im BMP format as bob1.bmp. Opened it again in image tool but there is no way I see to resave it in dxt1+alpha...I just saved it and I see no difference....I did find a solution.....that the way to maintain the same appearance "no alpha" conversions give (my preference...they seem higher resolution) is to merely switch to Elrond's nvidia method when you have alpha masks. I have a GeForce videocard..but don't know if that's the reason.Kirk Olsson's F-86 over Morrisville, Vermont....I've come a long way, baby.

[LuisFelizTirado 33]

Hello John,Way back then, Elvish used Martin Wright's graphics dlls for his tool; he did not develop image conversion algorathims of his own.Martin had extensively documented the degradation and had recommended the use of the nVidia method instead. It was so long ago that it is no wonder that it is creating some confusion now. So, you have found the best solution.Anyway, your image is gorgeous and those ground textures look great, with very nice color. Congratulations!Best regards.Luis