Now I have spent quite some time converting to dds with these programs and testing in CFS3:
ImageTool CFS3 188.8.131.52
ImageTool FS2004 184.108.40.206
ImageTool FSX SP1 10.0.61355.0
ImageTool FSX SP2 10.0.61472.0
Paint Net 3.5.8
Paint Shop Pro 7.02 Nvidia plugin 3.02
It’s only ImageTool 220.127.116.11 that makes terrain mipmaps as good as the original CFS3 terrain tiles, at least on my computer and I have an ATI videocard. It doesn’t matter if it’s dxt1 or dxt3 with or without alpha mask.
In these pictures you can clearly se the difference:
Converted to dds with mipmaps using the Nvidia plugin.
Converted to dds with mipmaps using ImageTool 18.104.22.168.
I have a sneaking feeling that imagetool does something special with the mipmaps that is optimised for FS/CFS.
DXTBmp uses the nVidia DDS library to output textures. The Photoshop plugin uses the same libraries and I wouldn`t be surprised if the other programs also use code based on the nVidia library. I would expect all these methods to create very similar results
I remember using the commandline options in imagetool and there is a flag you can set to specify that the output is to be used for terrain. My guess is that it sets something in the file that tells FS/CFS to switch mipmaps at a greater distance than normal so making it look slightly sharper for longer. Its not that the image data is any better just that it holds on to the higher mipmaps for longer. In the same way that aircraft can be made to look sharper by removing the mipmaps (so forcing the use of the full image at all distances) delaying the switch to the next mipmap will extend the distance before terrain switches to a smaller (blurrier) mipmap.
On the other hand it is possible that the mipmap scaling algorithm used by imagetool is different to nVidia and creates mipmaps that are particularly optimised for terrain. The nVidia code is not FS-Specific as most games these days use DDS. There are options available in the plugin (and DXTBmp) to use different scaling algorithms and it may be worth experimenting with these to see if they make any difference in this situation.
Or just use imagetool (for the final output at least)
Yes, I noticed there was a terrain flag, but I didn’t use it in my tests.
It was also a surprise to me that it was only the CFS3 ImageTool that gave a sharp terrain look in CFS3. DDS tiles converted by later ImageTool versions looked similar to those converted by the Nvidia plug-in, when I tested in CFS3.
If I open the converted dds files and compare the mipmaps created by different programs/settings they all look the same.
So I guess you are right about there’s some special optimizing in ImageTool for the Microsoft CFS/SF titles.
Thanks for sharing your insight regarding this!
Very much appreciated!