UPDATED ON FEBRUARY 24, 1998 LP FILES ***************************************************************************** DESCRIPTION ***************************************************************************** LP files define the movement of the computer-controlled cars at a track. Each track must have all nine of these files to run properly. IndyCar Racing tracks do not have these LP files. ***************************************************************************** WHICH LP FILE DOES WHAT? ***************************************************************************** FILE PURPOSE ---- ------- RACE.LP - Determines the movement of the computer cars under green flag when not running near any other cars. MAXRACE.LP - The car will ride the inside of the race track at a very slow rate of speed (along the yellow or white line). Determines the inside of the racing surface. MINRACE.LP - The car will ride along the outside wall at a very slow rate of speed at a very slow rate of speed. Determines the outside of the racing surface. PASS1.LP - Determines the movement of the computer cars under green flag when being passed on the left. PASS2.LP - Determines the movement of the computer cars under green flag when being passed on the right. This lp file moves to the inside of the race.lp file on straights and to the outside of race.lp in corners. PACE.LP - Determines the movement of the computer cars under yellow flag conditions. This kicks in as soon as the car crosses the start/finish line to take the yellow flag. PIT.LP - Determines the movement of the computer cars during pit stops. MAXPANIC.LP - Drives along outside wall along straights and in corners drives from outside wall to inside of pit inner pit wall by start of next straight then suddenly juts out to outside wall on the straight. This would explain some of the weird ai movements during pitting and it leads me to believe this file is somehow associated with pitting. Also may provide escape during accidents for the ai. MINPANIC.LP - The strangest of all the ai files by far. This file follows the innermost lines possible. For example at Bristol the cars will follow the outside of the pitwall along the straight then turn suddenly left to the infield guardrail and follow it along through the turns until it reaches the next pitwall, turn suddenly right to the outside of the pitwall, follow it on the outside to the end, then turn suddenly left again to corner guardrail, then turn suddenly left and follow it to the next pit wall. In Nascar 2 this file has weird affects on the spotter voice. It's use is a real mystery and is probably best left alone until more is understood about it. This file seems to define the innermost driveable surface (whether grass or whatever available). SPOTTER.LP - Nascar 2 only. Unknown use as of yet. What I can tell you about it is this. At Bristol for example the ai ride the pit wall and then follow the white line along the corners to the next pit wall. The speeds are very slow. Since the other lp files define the inside and outside racing surfaces and such, I assume that this one defines the position on the race track and in someway works with the track.txt file to determine what *.wav file is played for the spotter voice. Sound logical? I haven't tested this yet, but it's the only theory I have at the moment. ***************************************************************************** STRUCTURE ***************************************************************************** An LP file consists of two sections only. The first section is the header containing the number of records in the file. The second section contains that many records. SECTION ONE: The Header ----------------------- The number of records is stored as an unsigned long integer in the first four bytes of the file. The number of records at a track is proportional to the length of the track. SECTION TWO: The Records ------------------------ Each record consists of three fields. Each field is a 4-byte signed long integer. The records are stored right after the header, starting with the record that represents the beginning of a lap, and eding with the record that represents the end of a lap, moving along the track in the same direction as the cars travel. Using the original nine NASCAR tracks, Chip Taylor calculated that records seem to correspond to positions that are approximately 11 feet apart, and that they start and end near the start/finish line. The first field contains a value that coresponds to the speed that the cars try to achieve at that point on the race track. If this record is for a position on the corner of a track, and the speed is great, the cars seem to slide into the outside walls (no damage though). The second field does some wierd stuff I haven't figured out yet... The third field coresponds to the line the cars take around the track. A value of zero places them on the middle of the track, a negative value places them farther to the right, and a positive value places them further to the left. ====================== SPECIAL NOTES by Chas: In ICR2 and the old N1 game (it has been corrected I think in N2) when the ai pitted they would bounce to the outside before pitting. This happened because control transferred from the race.lp file to the min files before finally transferring to the pit.lp file. I haven't seen this in n2 any longer. A second event I have noticed is this. When ai cars run bunched up (3 wide) control transfers momentarily to the min files before it transfers back to the pass or race files. This might be part of the reason we have been having some problem with having decent starts in the race in the N2 files but more research needs to be done one this. ------------------------- Corey Rueckheim Chas Bornemann 9/24/97 BB&B Track Project http://simcyberworld.simplenet.com/ Special thanks to Chip Taylor for info provided to Corey to start this file.