Reading BGL files

[Chris Knipe]

Hi,

I'm trying to read BGL files in .NET, following the documentation at https://www.fsdeveloper.com/wiki/in...GL file is made,dependent on the section type.

Using P3Dv5 as a test, and for consistency I am reading the same(?) BGL file as used in the example on the wiki article. For the header, below is my 56 bytes

C:\Games\Prepar3D\Scenery\0301\scenery\cvx2815.bgl
65 0 0 0 1 0 0 0 86 8 0 0 63 91 60 2 60 88 0 0 6 0 0 0 0 FA 81 0 0 0 0 0 44 3 0 0 F4 4 0 0 26 8 0 0 6F 3E 1 0 1B 1C 0 0 86 7D B0 CE
65

The second line, is my DWORD (Int32) generated from the first 4 bytes, 0x00 to 0x03.

Is this correct, because from what I am reading, the Magic number is not 0x01, 0x02, 0x19, or 0x92?

private void ScanBGL(string thisFile)
{
Console.WriteLine(thisFile);
byte[] thisHeader = new byte[56];
using (System.IO.BinaryReader thisStream = new System.IO.BinaryReader(new System.IO.FileStream(thisFile, System.IO.FileMode.Open)))
{
thisStream.BaseStream.Seek(0x38, 0);
thisStream.Read(thisHeader, 0, 56);
}

Console.WriteLine(ByteArrayToHex(ref thisHeader));
Console.WriteLine(Hex(BitConverter.ToInt32(thisHeader, 0)));
}

private string ByteArrayToHex(ref byte[] ByteArray)
{
long l;
string strRet = "";

for (l = Information.LBound(ByteArray); l <= Information.UBound(ByteArray); l++)
strRet = strRet + Hex(ByteArray[System.Convert.ToInt32(l)]) + " ";

ByteArrayToHex = Left(strRet, Strings.Len(strRet) - 1);
}

 

[DragonflightDesign]

The header is zero-based, IIRC In that case, the line should be

byte[] thisHeader = new byte[55];

 

[Chris Knipe]

Ok,

Granted I am reading one byte too many.

But we are talking (or I am asking), about the first 4 bytes? Surely, whether I read 55 or 56 bytes, the first 4 bytes will remain the same, as the offset in the file where they are being read from remains 0?

 

[WarpD]

I'm uncertain what actual language you're using... but...

Isn't this line:
thisStream.BaseStream.Seek(0x38, 0);

Actually saying to seek to position 0x38 after position 0... which would put you beyond the file header and instead put you at the first section in the BGL file??

 

[DragonflightDesign]

It's C# Ed; and yes, I agree - it looks like the OP has gotten caught by the zero-based start again.

 

[Chris Knipe]

I'm uncertain what actual language you're using... but...

Isn't this line:
thisStream.BaseStream.Seek(0x38, 0);

Actually saying to seek to position 0x38 after position 0... which would put you beyond the file header and instead put you at the first section in the BGL file??

Sorry, I feel like an idiot!! Seek(0, 0) to go to the start of the file, and I am getting 0x01, 0x02, 0x92, and 0x19 just like I am supposed too!

 

[DragonflightDesign]

It happens, trust me!

 

[Chris Knipe]

Getting there

Processing Section 1 of 11, C:\Games\Prepar3D\Scenery\0102\scenery\APX14160.bgl
Airport
Processing Section 2 of 11, C:\Games\Prepar3D\Scenery\0102\scenery\APX14160.bgl
170
Processing Section 3 of 11, C:\Games\Prepar3D\Scenery\0102\scenery\APX14160.bgl
ILSVOR
Processing Section 4 of 11, C:\Games\Prepar3D\Scenery\0102\scenery\APX14160.bgl
NDB
Processing Section 5 of 11, C:\Games\Prepar3D\Scenery\0102\scenery\APX14160.bgl
Marker
Processing Section 6 of 11, C:\Games\Prepar3D\Scenery\0102\scenery\APX14160.bgl
Waypoint
Processing Section 7 of 11, C:\Games\Prepar3D\Scenery\0102\scenery\APX14160.bgl
SceneryObject
Processing Section 8 of 11, C:\Games\Prepar3D\Scenery\0102\scenery\APX14160.bgl
VORILSICAOIndex
Processing Section 9 of 11, C:\Games\Prepar3D\Scenery\0102\scenery\APX14160.bgl
NDBICAOIndex
Processing Section 10 of 11, C:\Games\Prepar3D\Scenery\0102\scenery\APX14160.bgl
WaypointICAOIndex
Processing Section 11 of 11, C:\Games\Prepar3D\Scenery\0102\scenery\APX14160.bgl
NameList

Anyone that can be friendly and identify what Section Type 170 (0xAA) is?

 

[hervesors]

Hi Chris,

0xAA is the AirportSummary section identifier (P3DV5 and V6 only) - Was 0x2C in previous versions as well as in FSX

Hervé

 

[Chris Knipe]

Thanks a mil Herve!