AGN (FSX)

Applicable
MS Flight
FSXA
FSX
FS2004
FS2002

This document describes the FSX format for autogen (AGN) files. This description is not yet complete, so feel free to add more information if you have any.

Sections

The AGN file uses the RIFF format (like MDL files), this means that the file consists of different sections. Each section starts with a four character label, followed by the length of the section in bytes (this length without the header itself).

The main RIFF section itself has one additional parameter, this is a four character string that indicates the type of RIFF AGN file. For an FSX AGN file the value should always be AGNX.

The following subsection show more details about the content of these different sections.

VERS

Contains versions information about the AGN file.

 int32 version (normally 1091777331)

GBDD

Contains information about autogen generic buildings

 int32 percentage of 1 and 2 floor buildings (normally 10)
 int32 percentage of 3 to 5 floor buildings (normally 10)
 int32 percentage of 6 to 8 floor buildings (normally 10)
 int32 percentage of 9 to 12 floor buildings (normally 10)

Valid values for percentage are from 0x00 (0%) to 0x14 (100%).

GBLD

Contains building information. This section contains one or more GBLR sections.

GBLR

Contains information about Generic Buildings.

 GUID roof type (will use default roofs, if 0)

For each Generic Building:

 float X position of first point 
 float Y position of first point
 float X direction to the second point
 float Y direction to the second point
 float X offset of third point
 float Y offset of third point 

The x and y coordinates are given as offset from the middle of the LOD13 square (range -0.5 till 0.5).

PREG

Contains vegatation information. This section contains one or more PRDE sections.

PRDE

For vegatation polygon. Contains:

 GUID vegatation type

For each polygon:

 int number of vertices

For each vertex:

 single x
 single y

The x and y coordinates are given as offset from the top left of the LOD13 square (range 0 till 1).

VGRG

Contains information about pre-FSX style rectangular vegetation regions. This section contains one or more VGRE sections.

VGRE

 GUID vegetation type

For each rectangle:

 float X position of first point
 float Y position of first point
 float X offset to second point
 float Y offset to second point 

The x and y coordinates are given as offset from the middle of the LOD13 square (range -0.5 till 0.5).

ROWH

Contains information about row houses. The amount of houses is the length of the section divided by 24.

For each row house:

 float X position of first point
 float Y position of first point
 float X direction to second point
 float Y direction to second point
 float X offset to third point
 float Y offset to third point 

The x and y coordinates are given as offset from the middle of the LOD13 square (range -0.5 till 0.5).