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GOURANGA! Forums > Editing > General > Respawning Cars in GTA2 Multiplayer

Post 1 | New

Posted July 6th, 2008

Cerbera
Ben 'Cerbera' Millard

Joined: Feb '03
Posts: 1,808

How do you make cars respawn in multiplayer GTA2 levels?

Also, are there any desynchronisation problems with doing it?

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Grand Theft Auto Handling Editor
GTA Tutorials

Post 2 \| New	Posted July 10th, 2008. Updated July 10th, 2008
Sektor Joined: Feb '03 Posts: 298	Code: PLAYER_PED p1 = ( 12.5 , 18.5 , 2.0 ) 10 0 car_data car1 COUNTER gameloop = 1 LEVELSTART car1 = CREATE_CAR ( 11.5 , 17.5 ) 28 90 COPCAR END WHILE ( gameloop = 1 ) IF ( is_car_wrecked ( car1 )) car1 = CREATE_CAR ( 11.5 , 17.5 ) 28 90 COPCAR END ENDIF ENDWHILE LEVELEND That could create a chain reaction of explosions if the car is wrecked at the respawn location. You could avoid that by only respawning the car when it's not on the player's screen. Code: IF ( NOT ( IS_ITEM_ONSCREEN ( car1 ) ) ) IF ( is_car_wrecked ( car1 )) // DELETE_ITEM ( car1 ) // I don't think you need this car1 = CREATE_CAR ( 11.5 , 17.5 ) 28 90 COPCAR END ENDIF ENDIF Respawning cars doesn't cause sync problems but a chain reaction of explosions could make the game go out of sync or crash. ------------------ Stealing cars is the easy part

Post 2 | New

Posted July 10th, 2008. Updated July 10th, 2008

Sektor

Joined: Feb '03
Posts: 298

Code:

PLAYER_PED p1 = ( 12.5 , 18.5 , 2.0 ) 10 0

car_data car1

COUNTER gameloop = 1

LEVELSTART

car1 = CREATE_CAR ( 11.5 , 17.5 ) 28 90 COPCAR END

WHILE ( gameloop = 1 )

IF ( is_car_wrecked ( car1 ))
car1 = CREATE_CAR ( 11.5 , 17.5 ) 28 90 COPCAR END
ENDIF

ENDWHILE

LEVELEND

That could create a chain reaction of explosions if the car is wrecked at the respawn location. You could avoid that by only respawning the car when it's not on the player's screen.

Code:

IF ( NOT ( IS_ITEM_ONSCREEN ( car1 ) ) )
  IF ( is_car_wrecked ( car1 ))
   // DELETE_ITEM ( car1 ) // I don't think you need this
   car1 = CREATE_CAR ( 11.5 , 17.5 ) 28 90 COPCAR END
  ENDIF
ENDIF

Respawning cars doesn't cause sync problems but a chain reaction of explosions could make the game go out of sync or crash.

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Stealing cars is the easy part

Post 3 | New

Posted July 10th, 2008. Updated July 10th, 2008

Cerbera
Ben 'Cerbera' Millard

Joined: Feb '03
Posts: 1,808

Thanks for the help! I didn't even know where to start.

I only want the car to respawn when you can't see the spawnpoint. I found IS_POINT_ONSCREEN to do that.

To avoid chain reactions, the new car must only spawn when the spawnpoint is clear. I found IS_CAR_IN_BLOCK with a width and height of 2.0 does that nicely.
Code:

This works great for nearly all cases. It's currently released in MultiSlayer Ghetto arena.

However, if you wreck the car at the spawnpoint, the wreck never gets cleared. I need to clear the wreck when IS_CAR_IN_BLOCK is TRUE. I tried this:
Code:

// Respawning FBI Car:
IF (IS_CAR_WRECKED(fbicar))
IF (NOT (IS_POINT_ONSCREEN(184.5,149.5,2.0)))
  IF (NOT (IS_CAR_IN_BLOCK(fbicar, 184.5,149.5,2.0, 1.0,1.0)))
   // Cannot see spawnpoint and spawnpoint is clear:
   fbicar = CREATE_CAR (184.5,149.5) -1 000 EDSELFBI END
   GIVE_WEAPON (fbicar, CAR_MACHINE_GUN, 99)
  ELSE
   // Cannot see spawnpoint but wreck overlaps spawnpoint:
   DELETE_ITEM (fbicar) // clearing the wreck doesn't work?
   fbicar = CREATE_CAR (184.5,149.5) -1 000 EDSELFBI END
   GIVE_WEAPON (fbicar, CAR_MACHINE_GUN, 99)
  ENDIF
ENDIF
ENDIF

If I can clear the wreck from the spawnpoint, this respawn will be perfect!

I tried MISSION_HAS_FINISHED, running far away, waiting a long time, then returning but the wreck remained at the spawnpoint.

Would using a GENERATOR to create the vehicle as if it were a powerup be more successful?

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Grand Theft Auto Handling Editor
GTA Tutorials

Post 4 \| New	Posted July 11th, 2008. Updated July 13th, 2008
Sektor Joined: Feb '03 Posts: 298	DELETE_ITEM doesn't remove wrecks. GENERATOR can't create vehicles. PUT_CAR_ON_TRAILER works great for teleporting a wreck to another location and GTA2 doesn't seem to mind 100+ wrecks being put on the same trailer. Code: PARKED_CAR_DATA parked_trailer_1 = ( 178.1 , 153.0 ) 19 0 truktrns PARKED_CAR_DATA truck1 = ( 178.1 , 154.3 ) 19 0 TRUKCAB1 WHILE_EXEC (loopage = 1) // Respawning FBI Car: IF (IS_CAR_WRECKED(fbicar)) IF (NOT (IS_POINT_ONSCREEN(184.5,149.5,2.0))) PUT_CAR_ON_TRAILER ( fbicar, parked_trailer_1 ) fbicar = CREATE_CAR (184.5,149.5) -1 000 EDSELFBI END GIVE_WEAPON (fbicar, CAR_MACHINE_GUN, 99) ENDIF ENDIF ENDWHILE If you don't want the car to respawn as soon as it's offscreen then you can add a delay: Code: IF (NOT (DELAY (50))) fbicar = CREATE_CAR (184.5,149.5) -1 000 EDSELFBI END ENDIF If a vehicle spawns on top of a player, it will kill them and cause weird results (like turn them into a ped) but IS_POINT_ONSCREEN should prevent that. ------------------ Stealing cars is the easy part

Post 4 | New

Posted July 11th, 2008. Updated July 13th, 2008

Sektor

Joined: Feb '03
Posts: 298

DELETE_ITEM doesn't remove wrecks.

GENERATOR can't create vehicles.

PUT_CAR_ON_TRAILER works great for teleporting a wreck to another location and GTA2 doesn't seem to mind 100+ wrecks being put on the same trailer.
Code:

PARKED_CAR_DATA parked_trailer_1 = ( 178.1 , 153.0 ) 19 0 truktrns
PARKED_CAR_DATA truck1 = ( 178.1 , 154.3 ) 19 0 TRUKCAB1

WHILE_EXEC (loopage = 1)

// Respawning FBI Car:
IF (IS_CAR_WRECKED(fbicar))
   IF (NOT (IS_POINT_ONSCREEN(184.5,149.5,2.0)))
   PUT_CAR_ON_TRAILER ( fbicar, parked_trailer_1 )
   fbicar = CREATE_CAR (184.5,149.5) -1 000 EDSELFBI END
   GIVE_WEAPON (fbicar, CAR_MACHINE_GUN, 99)
  ENDIF
ENDIF

ENDWHILE

If you don't want the car to respawn as soon as it's offscreen then you can add a delay:
Code:

IF (NOT (DELAY (50)))
fbicar = CREATE_CAR (184.5,149.5) -1 000 EDSELFBI END
ENDIF

If a vehicle spawns on top of a player, it will kill them and cause weird results (like turn them into a ped) but IS_POINT_ONSCREEN should prevent that.

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Stealing cars is the easy part

Post 5 | New

Posted July 12th, 2008

Cerbera
Ben 'Cerbera' Millard

Joined: Feb '03
Posts: 1,808

That's a delightful bit of evil! The relevant parts I've ended with are this:
Code:

// Cars
CAR_DATA fbicar
PARKED_CAR_DATA trailer = (1.0,1.0) 19 90 TRUKTRNS

...

// Respawning FBI Car:
IF (IS_CAR_WRECKED(fbicar))
IF (NOT (DELAY (100))) // let explosion happen
  IF (NOT (IS_POINT_ONSCREEN(184.5,149.5,2.0)))
   IF (IS_CAR_IN_BLOCK(fbicar, 184.5,149.5,2.0, 1.0,1.0))
   // Cannot see spawnpoint but wreck is blocking spawnpoint:
   PUT_CAR_ON_TRAILER (fbicar, trailer)
   DELETE_ITEM (fbicar)
   ENDIF

   // Cannot see spawnpoint and spawnpoint is clear:
   fbicar = CREATE_CAR (184.5,149.5) -1 000 EDSELFBI END
   GIVE_WEAPON (fbicar, CAR_MACHINE_GUN, 99)
  ENDIF
ENDIF
ENDIF

This seems to work perfectly. You have to be away from the spawnpoint for a few seconds for any of the respawning stuff to happen, which is a nice touch. Thanks for your help!

I created a little piece of land in the top left of the map so the TRUKTRNS is very far away. default.txt says DELETE_ITEM is intended for use with any scripted item, including cars. Even if the item stays in the game world, at least it can recover the scripting resources?

If the car is wrecked away from the spawnpoint, I let the wreck remain in the level.

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

Grand Theft Auto Handling Editor
GTA Tutorials

Post 6 \| New	Posted July 13th, 2008. Updated July 14th, 2008
Sektor Joined: Feb '03 Posts: 298	Cerbera wrote: If the car is wrecked away from the spawnpoint, I let the wreck remain in the level. Good idea. That's a nice improvement. GTA2 Scripting.doc wrote: DELETE ITEM Orders the game to delete a previously created car/object/character/light. This generic command replaces the DELETE_CAR/CHAR/OBJECT commands Oh yeah, it does say it works with cars but Rockstar didn't use it on any cars (at least not in the Industrial level). I was having problems with delete_item crashing the game but it was probably trying to delete an item that didn't exist. I'll have to check that. You don't have to create land for the trailer, it works fine underwater (although probably not meant to be used that way). I think respawning cars are useful enough to add to your GTA2 scripting tutorials. ------------------ Stealing cars is the easy part

Post 6 | New

Posted July 13th, 2008. Updated July 14th, 2008

Sektor

Joined: Feb '03
Posts: 298

Cerbera wrote:

If the car is wrecked away from the spawnpoint, I let the wreck remain in the level.

Good idea. That's a nice improvement.

GTA2 Scripting.doc wrote:

DELETE ITEM
Orders the game to delete a previously created car/object/character/light. This generic command replaces the DELETE_CAR/CHAR/OBJECT commands

Oh yeah, it does say it works with cars but Rockstar didn't use it on any cars (at least not in the Industrial level). I was having problems with delete_item crashing the game but it was probably trying to delete an item that didn't exist. I'll have to check that.

You don't have to create land for the trailer, it works fine underwater (although probably not meant to be used that way).

I think respawning cars are useful enough to add to your GTA2 scripting tutorials.

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Stealing cars is the easy part

Post 7 | New

Posted July 17th, 2008. Updated July 18th, 2008

Cerbera
Ben 'Cerbera' Millard

Joined: Feb '03
Posts: 1,808

I have now written Respawning Vehicles in GTA2 Coding.

I'm guessing DELETE_ITEM is unused because they usually get released some other way. Such as parking in a garage, going into a DESTUCTOR, changing the driver into a civilian and things like that? Even if it does nothing, it seems like the right thing to do.

As you suggested writing the article, I'm guessing you're fine with people redistributing the code.

While I was there, I noticed the GTA2 Characters guide was really huge. So I've split a couple of sections from it:

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Grand Theft Auto Handling Editor
GTA Tutorials

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