re3

Intro

The aim of this project is to reverse GTA III for PC by replacing parts of the game one by one such that we have a working game at all times.

How can I try it?

• re3 requires game assets to work, so you need to own a copy of GTA III.
• Since re3 is a DLL that works with original GTA III for now, you need Simple DLL Loader. You can get it here.
• Build re3 or download it from one of the above links (Debug or Release).
• Make sure you included the re3 in plugins.cfg or dlls.cfg.
• re3 starts the script main_freeroam.scm that comes along with it by default, so you should copy it to from gamefiles/ to your game's data/ directory.

Notice

If you want to load original script/story, press and hold G while game is loading. This includes both starting new game and loading save game.

Notice if you will build it

There are various settings at the very bottom of config.h, you may want to take a look there. i.e. FIX_BUGS define fixes the bugs we've come across.

https://github.com/GTAmodding/re3/tree/master/src/core/config.h

I want to contribute, where should I start?

A good approach is to start at the fringes of the code base, i.e. classes that don't depend on code that we don't have reversed yet. If a function uses only few unreversed functions that would be inconvenient to reverse at the time, calling the original functions is acceptable.

Unreversed / incomplete classes (at least the ones we know)

cAudioManager - WIP
CBoat
CBulletInfo
CExplosion
CMenuManager - WIP
CObject
CPacManPickups
CPedPath
CPools - save/loading
CRecordDataForChase
CRecordDataForGame
CRoadBlocks
CSkidmarks
CStats
CTrafficLights
CWeapon
CWeather
CWorld
GenericLoad

The following classes have only unused or practically unused code left:

CCullZone - only mobile stuff
CCullZones - only mobile stuff
CFileLoader - almost done
CSceneEdit

Coding style

I started writing in Plan 9 style, but realize that this is not the most popular style, so I'm willing to compromise. Try not to deviate too much so the code will look similar across the whole project.

To give examples, these two styles (or anything in between) are fine:

type
functionname(args)
{
	if(a == b){
		s1;
		s2;
	}else{
		s3;
		s4;
	}
	if(x != y)
		s5;
}

type functionname(args)
{
	if (a == b) {
		s1;
		s2;
	} else {
		s3;
		s4;
	}
	if (x != y)
		s5;
}

This one (or anything more extreme) is heavily discouraged:

type functionname ( args )
{
  if ( a == b )
  {
    s1;
    s2;
  }
  else
  {
    s3;
    s4;
  }
  if ( x != y )
  {
    s5;
  }
}

i.e.

• Put the brace on the same line as control statements

• Put the brace on the next line after function definitions and structs/classes

• Put an else on the same line with the braces

• Don't put braces around single statements

• Put the function return type on a separate line

• Indent with TABS

As for the less cosmetic choices, here are some guidelines how the code should look:

• Don't use magic numbers where the original source code would have had an enum or similar. Even if you don't know the exact meaning it's better to call something FOOBAR_TYPE_4 than just 4, since 4 will be used in other places and you can't easily see where else the enum value is used.

• Don't just copy paste code from IDA, make it look nice

• Use the right types. In particular:

  • don't use types like __int16, we have int16 for that

  • don't use unsigned, we have typedefs for that

  • don't use char for anything but actual characters, use int8, uint8 or bool

  • don't even think about using win32 types (BYTE, WORD, &c.) unless you're writing win32 specific code

  • declare pointers like int *ptr;, not int* ptr;

• As for variable names, the original gta source code was not written in a uniform style, but here are some observations:

  • many variables employ a form of hungarian notation, i.e.:

  • m_ may be used for class member variables (mostly those that are considered private)

  • ms_ for (mostly private) static members

  • f is a float, i or n is an integer, b is a boolean, a is an array

  • do not use dw for DWORD or so, we're not programming win32

• Generally, try to make the code look as if R* could have written it

Environment Variables

Here you can find a list of variables that you might need to set in windows:

"GTA_III_RE_DIR" * path to "gta3_re" game folder usually where this plugin run.
"GTA_III_DIR" * path to "GTAIII" game folder.