FS X BGL file structure

I tried to put together evrything I have learned about the bgl file structure in FS X in one document which I want to make available to all of you; you find it attached to this post. I would be grateful for any comments and corrections.
Winfried

Thanks Winfried,

I have been doing the same thing as I develop SDE. I will let you know if there is anything that I have found which you do not have in your document

This is pretty much the showcase of when to use a Wiki indstead of a document maintained by a single person.

Given that Wifried is pretty much the only person that I know of who has identified the bgl format for both FS9 and FSX and made the information available to the community it seems fair enough to me at the moment. There is a section in the Wiki where he has put some of the information and I am sure it will end up there in due course

I am sorry, but my experience with the WIKI format was rather negative: it is much too difficult to put the data into a tabular format.

Hi Winfried

I would not be concerned about that. I have the same problem For me, the most important thing is that the information is available and Thank you.

I fully agree with Winfried and Jon.
The most important fact is to produce the materials and not where.

a Happy Newyear and a Happy design one too...
Bert

Many thanks for providing that information and keep up the good work !
It will for sure help me getting started with parsing them bgl's for stuff that i need to know in my addon.

And a happy new year to all of you!

Hi Winfried

I am looking at the 0x003b record which, as you say, is present in each FSX airport. I am wondering if it is related to the airport 'polygon' in some way. I seem to recall in FS9 there was a separate set of bgl files containing airport backgrounds. Are these now in the cvx files? The backgrounds obviously can't be made using bglComp - although that would have been rather nice

Thanks a ton, been looking forward to that.

Page 3, second table:
Airport data should have ID 0x3c. Have not checked the other ones yet, but that one caught my eye immediately.

EDIT
Actually I might be wrong - the ID within the pointer seems to have remained 0x0003 while the actual record has 0x3c. Shame on me.

bertvk said:

I fully agree with Winfried and Jon.
The most important fact is to produce the materials and not where.

a Happy Newyear and a Happy design one too...
Bert

Click to expand...

You use a Wiki because of how the material is created. Hence recommending the Wiki has abselutely nothing to do with where it is done.

Beacons

Winfried,

I can't find mention of Beacons in the document. They have an ID of 0x011 in FSX. I think you refer to them in attachedObject but they can also exist as a stand-alone object in FS9 and FSX. The Beacon code being nested in a SceneryObject. I have done a test with SDE and I can create a stand-alone beacon which compiles fine and decompiles also as a Scenery Object with type ID of 11.

EDIT
It is also interesting to note that the compiler throws out any MILITARY beacon which has a HELIPORT or SEA_BASE base type. The only acceptable option is AIRPORT. There is no mention of that in the SDK that I can find

Maybe I forgot those beacons being used as seperate objects. You are perfectly right, they can be used that way (although up to now I have not found an instance of that in the MS scenery files ...) The obvious use of them is the attachment on top of a tower or a special base, MS has some special base for that purpose in the objects library.

FS9 compatibility and Small fix

osman said:

I tried to put together evrything I have learned about the bgl file structure in FS X in one document which I want to make available to all of you; you find it attached to this post. I would be grateful for any comments and corrections.
Winfried

Click to expand...

Hello Winfried,
I am trying to use your document with FS9 BGL files and it almost works fine, except some little problems. Do you know the differences between FS9 and FSX formats?
Or do you have the same document available for FS9?

Anyway, I noticed a small problem in the longitude transformation formula. The one I use is the following:
(double) lon = lon * 360.0 / (3 * 0x10000000) - 180.0
Just moving a parenthesis changed the result...

Thanks,
Eric

scruffyduck said:

Given that Wifried is pretty much the only person that I know of who has identified the bgl format for both FS9 and FSX and made the information available to the community it seems fair enough to me at the moment. There is a section in the Wiki where he has put some of the information and I am sure it will end up there in due course

Click to expand...

Hi,
Can you please let me know where the FS9 document is available?

Thanks,
Eric

EDIT
Please forget my request, I found it ;-)

FSX BGL file structure

Some comments/additions to try and add to the FSX structure brilliantly outlined by Winfried Orthmann's PDF.

Analysing all the apx, brx, atx, nvx files in FSX...

Headers
The value 0x1992 does indeed appear in all files as the version number in the header.

Of the three unknowns in the header starting at offset 12, the DWORD at 16 always begins 0x01C?????, the DWORD at 20 is always the value 0x08051803 (a magic number for FSX perhaps?).

The other unknowns at the end of the header, if viewed as DWORD dwReserved[7] followed by a WORD could be perhaps positions as Winfried suggests. As a general rule the DWORDs tend to increase in steps as:
00081A70,00081A73,00081A75,00081A76,00081A79,00081A7A,00081A7B,069F
though there are a few exceptions to this:
00081AA0,00081AA2,00081AA3,000206A9,00081AA8,00081AA9,00081AAD,0000
One thing common to all headers however is that when one of the earlier DWORDS is zero then so are all the values that follow it. Some headers just make use of one non-zero DWORD so that might tend to indicate that they are something other positions specifying an area. The first position is always non-zero anyway (required).

Section types
As well as the listed section types there are the types; 0x028, 0x029 and 0x02A. All three appear in apx files, while only 0x002A appears in atx files and only 0x0028 and 0x0029 in nvx files.

Subrecords
Of the 1525 apx bgl files searched I have only found \fsx\scenery\0001\scenery\apx03130.bgl that doesn't have a 0x003B subrecord. All the rest have.

Some apx files also have an unknown 0x003D subrecord of variable length and unknown meaning.

The unknown in TaxiwayPoint subrecords is indeed always 0x0000 (reserved).

0x028 and 0x029 are Vor2 and ndb2 records respectively. I have mentioned them in another post. Each record of these types are 12 bytes long. I have not had time to investigate whether there is anything useful in them or whether they are there to make the Scenery Engines' job easier. I've not encountered 0x02A but I will look out for it now