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SA ScrDebug

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TitleDownloadsFile sizeSubmitted
ScrDebug-0.570354.52 KB20 Sep 2012
ScrDebug-0.4r24158.24 KB11 Sep 2012
ScrDebug-0.44158.24 KB10 Sep 2012
ScrDebug.zip14756.68 KB29 Jun 2011
TitleSA ScrDebug
Games SA
SummaryRockstar-style script debugging reimplementation.
Rating5 (2 votes)
Submitted29 Jun 2011
Updated20 Sep 2012



During the development of GTA: San Andreas, Rockstar North used many features built-in to their scripting engine to aid debugging of scripts. Hacks, hidden modes, teleportation cheats, mission skippers, they had used them all. Obviously these features had to be locked away before San Andreas was released. This mods purpose is to re-implement them.

Little is known of Rockstars original debugging opcodes aside from what can be found in the GTA IV natives list and their usage within the main.scm and scripts in the script.img archive. However, I believe ScrDebug reimplements most opcodes with near exact functionality (if not, better).

There are several reasons to use this mod. One is that it enables certain "cheats" while playing San Andreas (gaining lives in arcade games, auto-aiming in pool game, skipping missions, increasing stats etc). Another is that, with some edits of SCM, it can be made to output information about SA Levels never before understood (see sapool.log in the ScrDebug folder).

But the best reason is for debugging of your own script mods. You can happily setup debug scripts and leave the debug code in there. The debug code is only enabled for those who have ScrDebug, thus not ruining a mod users gameplay with unexpected happenings. Even if you do want to remove the debug code after, most of these additional opcodes are very handy.


This mod supports the following .exe's:
  • HOODLUM 1.0 US
  • 1.0 US (Unknown, cracked variation)
  • 1.0 US Compact (listener's .exe)


An INI is included with this mod for customisation. You can toggle each opcode individually All opcodes are enabled by default. Feel free to disable opcodes when required.

There are two sections for opcodes. RsOpcodes contains opcodes that aim to simulate Rockstar's original debugging opcodes. NewOpcodes contains completely new opcodes which previously acted as NOP's (although similar opcodes may have existed of Rockstars).

In the Debug section, these settings exist:
  • Enable - inject opcodes (game must be restarted to stop using opcodes, as well as setting this to 0)
  • WriteToDebugFile - enables writing to debug log file
  • ShowRecentMessages - output messages on-screen (by 0662 and related opcodes)
  • MaxRecentMessages - max messages to display along the side of the screen (by 0662 and related opcodes)

New Opcodes



[No params]

When executed, the game will minimize and be frozen in it's current state. A HTML file named CRunningScript (open it in your web browser) will be placed in the SADebug folder which contains a list of the script variables (or mission variables, if a mission ran this opcode) and other information about the current script. Global Variables 2-1023 are also currently outputted (I will increase the range in a later version).

Information about the script object will also be written, including the address of it and the IP address, with which Cheat Engine can be used to further inspect the script.



0052 - PRINTVECTOR 98@ 100@ $TEMPVAR_FLOAT_3 99@ 100@ $TEMPVAR_FLOAT_3

[In] Float value
[In] Float value
[In] Float value
[In] Float value
[In] Float value
[In] Float value

Calculates the vector (difference between two 3D coord points) and prints the result on-screen.



[In] Int value

This opcode saves a number to the debug file, duh. Rockstar would have used it to check that values were correct.



[In] Float value

Just like 03A7 but for float numbers.



[No params]

Writes a newline to the debug file.



[In] void

This saves a string to the debug file. The value is an immediate 128 byte sequence. Unfortunately, Sanny removes this and replaces it with an integer, which refers to a place within it's debug.bin file - change that file if you wish to output strings. It's not easy, though.

In the example, it outputs "CURRENT_WANTED_LIST = " to the debug file. This goes right before the 03A7 example seen above. After that comes 03A9. So if the value of $CURRENT_WANTED_LIST was 2, it would output


To a line in the debug file. Effective.



[In] Int value
[In] 40 character string

This prints an integer, followed by a string, on-screen (a space is added between the string and integer automatically).



[In] 40 character string
[In] Float value

This prints a float, followed by a string, on-screen (a space is added between the string and integer automatically).


0661: "Message"

Prints a debug help message. This may have originally been a variation of PRINTSTRING, but as it's unused in the main.scm I decided to give a slightly different function for it.



[In] 40 character string

This prints a string on-screen. There can be a total of 12 strings printed onscreen at any time. The list of recent strings will appear at the side of the screen. This can be altered in the INI.



[In] 40 character string
[In] Int value

This prints a string, followed by an integer on-screen (a space is added between the string and integer automatically).



[In] 40 character string
[In] Float value

Like 0663 but with a float instead of an integer.



[In] See here: (also supports common ASCII keycodes)

This opcode is found to have the functionality of a keypress opcode. It tests if a key is being pressed. Most values found in the main.scm relate to ASCII keycodes exactly ("S" is used to skip most missions, number keys used to go to different mission stages, etc).

However, there are certain values found in the main.scm which do not relate to any ASCII keycode. I would assume either Rockstar had special values for certain keys or an alternate form of input was used while testing. Also consider that they would've developed SA with a PS2 Debugging Unit, so god knows what special hardware they could've hooked up to it...



[In] See here: (also supports common ASCII keycodes)

This opcode is like 0735. However when the key is pressed, this opcode only returns true once. Thus preventing looping of any key. So if the code was set to do something when that key was pressed, it would only happen once per press. Very useful. Especially over 0AB0.



[No params]

This opcode clears all the printed debug messages.



[Out] 16 character string (v$ or @v)

This opcode returns the last 16 characters of entered cheat input.

It's unknown how the input was originally produced, but the use is easily determinable from an exerpt of the GFAGNT script in the main.scm

08F8: show_update_stats 1
0004: $GF_WAIT_TIME = 500
0051: return

// a label would have been here, and a GOSUB to it would have been called elsewhere

091A: store_debug_command v$1221
    8846:   not is_string_null v$1221
    06D1: v$1225 = "DOCOOCHIE" // coochie == denise
        08F9: compare_string v$1225 v$1221

So somehow, the developers could input text and it could be recieved via 091A (and maybe elsewhere within the EXE?) in order to activate cheats within the scripts. The only use of this that still exists is in the GFAGNT script, but as that part of the script is never executed, main.scm modification is required to unlock the commands.

Or maybe they DID just use cheat input. If so, they would've had to have had another key somewhere to run 091B to clear the cheat string in case they made a typo while entering the cheat string.



[No params]

Clears the cheat code input.

RESET_CONSOLE_COMMAND is a NULL GTA4 native command name. A lot of NULL GTA4 functions are names of commands that existed in GTASA, however many aren't. Since this is the only remotely relatable name for 091B, and fits in with 091A, it gives room to believe that there could have been "console commands" used to trigger these cheats. But, maybe not.


ScrDebug 0.1b1
- Fixed some stability issues with text draw by clearing printed text on game restart.
ScrDebug 0.1b2
- Fixed all remaining stability issues with text draw by moving function position.
- Altered text style to look more like the debug text seen in early GTA:SA screenshots.
ScrDebug 0.2
- Added 086A
- Fixed bug where one of the debug messages would remain after game restart.
- Added 00CC
ScrDebug 0.3
- Extended 00CC
- Debug file name now chosen automatically based on script name (each script gets its own log file)
ScrDebug 0.4
- Added 091A
- Added 091B
ScrDebug 0.5
- Added 0052
- Added 065D
- Added 065E

SCM Features

One of the things that made me finally update ScrDebug to add 091A and 091B were because I wanted them for the Black Market mod. But I also realised how many debugging features in the SCM were still completely locked away, even with this mod. Perhaps one day I'll try to create a version of the main.scm which unlocks all of these without the need to start a new game. But for now, I'll just show you how to enable the most relevant one.

To enable cheat commands in the GFAGNT script WITHOUT having to start a new game, decompile the main.scm and make the following modifications...

Replace (offset = 141299):
ADD_BLIP_FOR_COORD 0.0 0.0 0.0 $GirlMarker[5]

00 00 00 00 00 00 00 00 00 00 00 00 00

Find (offset = 141401):


Find (offset = 152385):
091A: NOP v$1221


To use the offsets, decompile the main.scm with "CODE_OFFSETS" enabled in SB's Debug Options and use Ctrl+F (Find) to search for the line via it's offset, e.g. "{141299}".