Matti Laitinen's info

TRACK EDITING PROJECT

The aim of this project is to help people making new tracks for
F1GP or maybe even make a working track editor. If you want to
contribute to this project, please email any info/ideas etc. to
f1gp@alphaf1.com!

Here is what I've discovered so far:

Note!
* the offsets on this page are in decimal format

 byte = 1 byte  =  8 bits  (example: 0xAA)
short = 2 bytes = 16 bits  (example: 0xEE84)
 long = 4 bytes = 32 bits  (example: 0xE2D6AADD)


Open F1CT??.DAT to a hex editor.


4096:
always 0x1010 (short)

4098 short = 4102 short

4104:
offset checksum
read as short and add 4112 (=0x1010)
=> checksum offset = file_size-4

4108:
track data offset
read as short and add 4112 (=0x1010)

example: monza 8606+4112=12718



Track data
==========

28 bytes structure, same as in GP2

example:
 +0 angle start (short),
    angle=(signed integer)/(65536/360)=(signed integer)/(182.0444) 
 +2 height start (short)
 +4 start Y
 +6 start Z
 +8 start X
+16 right verge width at track sector 0 (unsigned byte)
+17 left verge width at track sector 0 (unsigned byte)


After this structure begins track sectors:
* Track sector 0 commands defination
* Track sector 0 attributes
* ...
* ...
* Track sector n commands defination
* Track sector n attributes


1. Track sector commands
- same as in GP2
- example: 
     * 0x80 object:
        -> arg0=distance from start of sector, arg1=object description
        offset
- command library documentation needed
  - 0xAC 5 args
  - 0xAA 4 args
  - 0x81 2 args
  - 0x99 4 args
  - 0x82 2 args
  - 0x85 3 args
  - 0x95 2 args
  - 0xAB 3 args
  - 0x90 2 args
  - ...


Note! Command number and arg0 are always unsigned byte
      arg1, arg2,... are always short type

Note!
 reading order: arg0, command number, arg1, arg2, arg3, ...


2. Track sector attributes
- Always stored in a 10 bytes structure (same as in GP2)
  +0 sector length (unsigned byte), 1 unit=16 feet=4.87 metres
  +2 sector arc (short),
     angle=(signed integer)/(65536/360)=(signed integer)/(182.0444)
  +4 height (short)
  +6 flags (short) kerbs, road signs, etc. (probably same as in GP2 ???)
  +8 right verge width (unsigned byte)
  +9 left verge width (unsigned byte)


Track data ends to 0xFFFF (short)

----------------