Problem with .gtx files

[Prom]

Good evening everyone,

Im currently looking into some files. This whole stuff is about game developement ( I know im kind of completly wrong in this forum for that matter ), to be accurate about terrains, tiles, heights, coordiante systems, positions, vectors, directions and so on. So basically everything needed to build up a proper 3D world. I already searched in magic google for like four days but hell i cant find any fitting answer and i downloaded like thousand programms already. I guess i just lack the knowledge...

Well, to the problem. I do have a heightmap in form of a .raw file. No problem. I now do have a layer (.lay) file given which seems to store some textures ( seen in hex editor, cant open it tho ). And other than that a folder containing .ilc files and several .gtx files. The map seems to be build up with a raster of 8x8 fields ( called polygon?? ), those fields seem to be represented by the .ilc files since the numaration is from 0-0 to 7-7 so 8x8 files. I assume that those files correspond to some kind of texture stored client sided or hold some data . And a changing number of .gtx files from map to map. I guess ( but i dont know, thats what im asking ) that those files hold some data of directions, vectors, maybe points or heightlevels of the map, i seriously dont know. But what i know is that, when opening it with a hex editor, the first lines say "geo" from which i came to the assumption that it has something to do with "vertical datum shift". Anyways i cant open those/that file so i wanted to ask if some knows an answer to this. Other than that a explanation of this .gtx file case would be great.
By the way, i already tried to open it with GDAL but for some case it say wrong dimension 1 x -1 something.

I attached examplefiles for each, .ilc, .lay and .gtx.
http://depositfiles.com/files/l1bpnn3kd
http://depositfiles.com/files/sml7rhw51
http://depositfiles.com/files/z0r6l8z7b

Thanks in advance ;)