GEOSCAPE.EXE

The "Geoscape" program that handles base management and aircraft, a.k.a. XCOM outside of tactical combat. TACTICAL.EXE handles combat.

NOTE: In the WinCE version, GEOSCAPE and TACTICAL are one executable, "UFO Defense.exe". Due to this confusion (what wiki pages place things on, when they're practically identical), currently GEOSCAPE, TACTICAL, and UFO Defense information appear here. (Unless and until someone wants to break everything up... then again, having highly related stuff in one place is a good thing.)

XCOM: UFO Defense (U.S. DOS) version 1.4

• Is 382,957 bytes long for the virgin 1.4 executable
• Has alien statistics starting at (non-offset) byte 379,729. There are 33 records of 39 bytes each. No alien names, though.
• If you have installed XcomUtil, it may alter the length of GEOSCAPE. Does anybody have a modified version, so we can put the length here? --MikeTheRed

XCOM Windows Collector's Edition

• Variously called the Win CE or Gold version on the wiki
• Is 495,616 bytes long
• Starting at byte 648, reads:

XCOM: UFO Defense Gold Edition
This awesome game was compiled on Sep  8 1999 at 08:57:11
Copyright - 1999 Hasbro Interactive/MicroProse Software
Party on dude.

• If you install XcomUtil, it separates your UFO Defense.exe into GEOSCAPE and TACTICAL executables. They are almost identical copies of UFO Defense.exe, however they start at the right place when run. This allows the game to closely mimick the Dos version by having its main loop run in a batch file.
• Has alien statistics starting at (non-offset) byte 480,145. There are 33 records of 39 bytes each. No alien names, though.
• Has tank & inbuilt alien weapon stats at byte 447,868 (see below)

Alien Stats

This section is for the structure of the alien stats, as found in GEOSCAPE. For actual data and additional information, see the alien statistics page. Also see Zombie's excellent alien stats page at StrategyCore. (Have YOU made your StratCore and XCOMUFO accounts yet?)

Alien stats are found as 33 records of 39 bytes each, in all versions of X-COM. They are identical in all versions. This data actually represents the "core" alien stats; modifiers are used to determine the final stats relative to game difficulty level. (In most, but not all, cases, the core stats are the same as the Beginner level stats.)

Alien stats start in each version of X-COM at the following location. This is a byte count, not an offset; with counts, the first byte in the file is byte 1:

Version        Location
DOS 1.4         379,729  (GEOSCAPE.EXE)  
WinCE Gold      480,145  (UFO Defense.exe)
Playstation     501,212
TFTD            486,930

Alien names are not actually found in Geoscape; it just has 33 strings of data... the alien each string applies to has been inferred by matching against aliens in the game.

The 39 bytes correspond to the following values. For the below, statements also apply to TFTD, since it's relevant to understanding the bytes:

0: Race

1: Rank

2: Unknown - Always 0

3: Can Fly

4: TUs

5: Health

6: Energy

7: Reactions

8: Strength

9: Firing Accuracy

10: Throwing Accuracy

11: Melee Accuracy

12: Armor - Front

13: Armor - Left Side

14: Armor - Right Side

15: Armor - Rear

16: Armor - Underside

17: Unknown - Always 0

18: Energy Recharge

19: Unknown - Always 0

20: Unknown - Always 1

21: Unknown - Always 0

22: Equals Unitref[48] and [52], whatever they are (see below)

23: Equals Unitref[48] and [52], whatever they are (see below)

These Unitref bytes ([48] and [52]) and now Geoscape Core values have long stumped us hardcore X-Commies. The two bytes always equal the same value for a given alien, including all aliens of the same race (the N's below). And, they're the same between Geoscape and Unitref. Clearly it must be important (or a goof!), but exactly what it is, who knows. Although this page is for X-COM, I've included TFTD in the hopes it helps folks - but it's been so long since I've played TFTD, I can't remember those units at all.

How's this for a thought?...

Dimension   Byte(s)

       X     22

       Y     23

       Z     24  (top when standing)
             25  (top when kneeling)
             26  (bottom)

Maybe they represent the "size in profile" ("width"), affecting likelihood to hit. A game could be tried with a target 20 squares away, set 22 and 23 alternately to 5 or 2 (or 1 or 0?), and see if it affects the successful shots percentage. 0 or even 1 might break the game, though.

Also, how do these values (2 to 5) correlate with the "pixel drawings" of units? I can't seem to find that info at the moment... aren't units and tiles defined as something like 16x16x28? If so, then perhaps the values (2 to 5) are multiplied by 3 or something to get their final "width" for bullet interception?? --MikeTheRed 05:20, 17 September 2006 (PDT)

I finally got the OSG (w00t!), and noticed the following: The section on weapon accuracy says (p. 221) that target size affects the chance to hit, and "the 'size' of each alien is listed along with all other alien statistics in Chapter 9". But the alien stats tables (p. 250 ff.) only lists Height as a possible 'size' stat, and the text write-ups don't otherwise address "target size" with any precision. This discrepancy - that Chapter 8 talks about size, but Chapter 9 only has height - might (might!) mean there are more variables that determine target area size, but somehow they didn't make it to the alien stats tables.

The description for Height (p. 249) does say, "Taller creatures are easier to hit than short ones are. An alien with a height of 40, for example, is twice as easy to hit as an alien with a height of 20." (Note: The tallest Height is actually 23. And also notice, Float is never mentioned.) This might mean only height affects this, or it could be read in a general way; other dimensions (X and Y in addition to Z) might also affect it.

Somebody should do some firing accuracy tests while hacking these potential X & Y bytes! But I still don't know how the values for [22] & [23] compare to what X-COM considers tile width... we know the Height byte accurately reflects the full range of possible values (0 to 23), but I doubt 5 is the full (pixel?) width of a tile. This might mean it's not width, then (or maybe [22] & [23] are added, or they are individually multiplied by 3 or something??) If anyone who knows about tile width could say something, I'd appreciate it. --MikeTheRed 11:24, 1 October 2006 (PDT)

In any event, here's a summary of bytes [22] and [23], in the hopes we can figure it out. They're always identical for a given race, and [22] always equals [23].

                 X-COM                            TFTD

         Value   Alien           N        Value   Alien           N

           2     Sectoid         6          2     Aquatoid        6   
                                                  Bio-Drone       1 
           3     Celatid         1                Tentaculat      1   
                 Chryssalid      1
                 Civilian        2          3     Calcinite       1   
                 Ethereal        3                Civilian        2   
                 Floater         6                Deep_One        1   
                 Muton           3                Gill_Man        4   
                 Snakeman        5                Tasoth          2   

           4     Cyberdisc       1          4     Coelacant       1   
                 Hovertank       1                Displacer       1   
                 Reaper          1                Hallucinoid     1   
                 Sectopod        1                Lobster_Man     5   
                 Tank            1                Triscene        1   
                                                  Xarquid         1 
           5     Silacoid        1  

24: Standing Height

25: Kneeling Height

26: Floating Height

27: Damage Modifier Category

This field is simply a look-up table, or more directly, a way to categorize the units into similar groups. The actual modifiers are listed elsewhere in the executable. A value of 1 indicates the first DM category, a value of 4 indicates the 4th, etc. The values of 2 and 3 are not seen in the alien stats as they refer to X-COM soldier armor info. I'm not sure about 13 as the Zombie's stats haven't been found yet, but I think there is a category in the DM's for it.

Column    Unit Type(s)
   1      Civilian, Sectoid, Celatid, Floater
   2      Personal Armor
   3      Power Suit, Flying Suit
   4      Tanks, Hovertanks
   5      Snakemen
   6      Ethereal
   7      Muton
   8      Silacoid
   9      Chryssalid
  10      Reaper
  11      Sectopod
  12      Cyberdisc
  13      Zombie

28: Psi Skill

29: Psi Strength

30: Bravery (encoded)

31: Motion scanner size

32: 1 for Cyberdisc, 0 for all others including TFTD... isn't "Explodes"; the TFTD Bio-Drone also explodes...

I edited the Cyberdisc's field to 0 and checked to see if it exploded. It still did. Obviously this field is for something else. I'll work on this some more. --Zombie 20:15, 15 September 2006 (PDT)

33: Unknown - Always 0

34: Corpse type

35: Big unit (2x2)

36: Victory point score

37: Aggression

38: Intelligence

Note: The fields that are always 0 or 1 could be modified to at least see where they appear in Unitref (fingers crossed). This may reveal what some of them are for (maybe they change during gameplay). --MikeTheRed

This data was just put together working heavily with Zombie and his great SC alien stats page.

Weapon Stats

The following info is for the WinCE version (UFO Defense.exe), but presumably is identical in other versions. It is probably in TACTICAL.EXE for the DOS version.

For WinCE, the tank and inbuilt alien weapon stats start at byte 447,868. These are 8 records of 20 bytes each. They're all stored in 16-bit (2 byte) words.

0: Damage type

1: Damage

2: Firing costs, etc.

Hmm... Ethereal, can you turn this into the usual offset structure? I'm not sure I'll get it right. (20 words must be 10 fields, but I see only 9 for the RTL example) --MikeTheRed 18:22, 15 September 2006 (PDT)

For example, the rocket tank's launcher will have values of: 2 (high explosive), 12 (default ammo), 85 (damage), 55, 45, 0 (aimed, snap, and auto costs), 115, 75, 0 (aimed, snap, and auto accuracies), etc.

Weapons are in this order:

Tank/Cannon

Tank/Rocket Launcher

Tank/Laser

Hovertank/Plasma

Hovertank/Launcher

Celatid

Cyberdisc

Sectopod