One more small update for this thread before I retreat temporarily into work mode - as per relevant info. in my previous post, have now done further tests and it is indeed possible to load DDS terrain files directly into FE2 (simplest is to point to relevant DDS files from within the general data ini file that resides in the "Terrains" folder).
Having said that, one peculiarity about loading of DDS terrains, instead of BMP ones - is that trees, buildings, other objects, etc., do not show up anymore. Once DDS files are converted to BMP format, on the other hand (as seen in the pics. in my previous post) - trees and buildings once again nicely come through.
So, unlike FlightGear that siphons in PNG-to-DDS converted satellite imagery (when its photo-scenery option is set up), FE2/SF2 would require conversion of DDS to BMP files, so as not to smother out the added immersion of objects and trees already present in/on the ThirdWire terrains.
Couple of pics. below with DDS ortho/photo-scenery being tested in the Mesopotamian theater in FE2. Graphics look quite good to me but unfortunate is the loss of trees and whatnot - so it's back to conversion to BMP format. Also, as evident in the pics. below, with careful choice of satellite photos the effects are not too jarring between different tiles when all are placed together. Not too bad for initial, manual placement of tiles - but very tricky to place correctly once you get towards rivers, seas/oceans, shorelines, and so on.
The job of a terrain modeler is not an easy one - virtual drinks on the house for all terra-formers, also for object-placement ini file crunchers.
One thing I particularly like about the satellite photo-scenery options in FlightGear is that, if you like, you can set things up in such a way that the scenery downloading/siphoning mechanism follows your aircraft as you fly, and nicely drops correctly placed terrains below, around, and in front of your flying path. Such a feature requires, once the photo-scenery siphoning system is set up, that you make sure to feed the following command/property to FlightGear itself:
--telnet=5000
The photo-siphoning mechanism then connects to local IP no. 127.0.0.1 (i.e., "localhost") on port 5000 and "feeds" satellite imagery to FlightGear as soon as terrain images are downloaded. Such an automatized process makes unnecessary the hassle of manually attempting to place photo-scenery tiles in correct places and positions. (Scenery can also be saved locally, for later offline use - without always having to re-download images.)
While there is no multiplayer capability in FE2 - theoretically, if the "telnet=5000" command could somehow be fed to the FE2.exe itself - then a simple re-duplication of one of the more accessible photo-siphoning mechanisms used by FlightGear (e.g., the Julia programming app linked to a photo-scenery Julia add-on) - might work for FE2 too.
Will post further thoughts in this thread if I find that there is any way to get the photo-scenery siphoning system to "talk" (establish a telnet connection) with FE2. Otherwise, it will be a very slow process of manually picking through, and choosing, satellite tiles - and that will be called up via the general data ini that's in the terrains folder.
Cheers all (& good dreams about auto-loading of satellite imagery in FE2),