persist.dat
The persist.dat file is the save-game and preference file for Oni. It can be edited most easily with GUI tools such as OSGE for Windows and OniLib for Mac, though OBD-style hex-based documentation of this file is given below.
The persist.dat file has nothing to do with Oni's .dat level files despite the ".dat" extension (it looks like Bungie West simply used .dat for every kind of file Oni read and wrote – saved_film####.dat, lvl_#_###_corpse.dat, etc. – until they later added .raw and then .sep as unique suffixes when they needed to break out some resource data from the levelX_Final.dat).
Progress saving
As players of Oni are well aware, the game does not allow arbitrary saving ("save anywhere"), but relies on the use of fixed save points activated by reaching certain places in each level, at which point the level scripting uses the BSL function save_game to mark your progress. This means that by deciding on a maximum number of levels and save points, Bungie West could store the total state of the player's progress in a fixed-size file – 206,496 bytes, to be exact.
As you will see below, many aspects of the game world are not saved in persist.dat; essentially, anything not pertaining to Konoko herself, such as the position of AIs and the presence of power-ups on the ground. What is stored is Konoko's position, health and inventory. Everything else is essentially hardcoded by the level scripting and will always be put in the same place when that save point is loaded.
Game preferences
In addition to save point data, persist.dat has a header section which stores Oni's preferences as chosen on the Options screen (note that this omits key bindings since they're stored in key_config.txt). It also records whether the cheats are enabled, i.e. whether you have beaten the game (however, cheats are unlocked at all times when playing with the Anniversary Edition or Daodan DLL installed or when using the Intel Mac build), as well as whether you killed Griffin in CHAPTER 13 . PHOENIX RISING.
Endianness
The Windows version of persist.dat stores its numbers in little-endian format. Bungie's original Mac game application and The Omni Group's Mac OS X port were built for PowerPC Macs, thus numbers were written big-endian (e.g., the 0x08 field in the header would be 00 0C 7F 5C). This meant that the save-game files were not compatible between Windows and Mac versions of Oni. However, with modern Macs running a native Intel build, the files are now saved in little-endian format and are thus interchangeable between Windows and Mac Oni.
Overview
The header of the file is 0x60=96 bytes long. It is followed by an array of 400 save points, 0x204=516 bytes each, grouped implicitly into 40 levels with 10 save points per level for a total of 206,400 bytes. The first 10 save points belong to level 0, which contains global game data rather than a specific level, thus they are never written to. The save points of the game's 14 levels follow. This leaves 25 unused level slots at the end of the save-game file.
Only the names of save points, not levels, are stored in this file (and they are all named uniformly as "Save Point n" even though they could say anything). The actual level names are taken from the ONLD resources in level0_Final, except for Chapter 1's name, "Syndicate Warehouse", which was hard-coded into the engine for a reason explained on the ONLD page.
Unlocking more levels
To unlock all possible levels, fill the range 0x08 to 0x28 with "FF". So far this has caused no problems, and allows you to add more levels to the game. Levels will not be visible unless there is a corresponding levelX_Final.dat in the GameDataFolder and an ONLD which matches this level number is found in level0_Final.dat. Levels above 39 are not unlockable due to the 40-level save point limit in the persist.dat.
Header data
| Offset | Type | Raw Hex | Value | Description |
|---|---|---|---|---|
| 0x00 | int32 | 0F 00 00 00 | 15 | version |
| 0x04 | int32 | 0E 0B D0 D0 | 0xD0D00B0E | signature |
| 0x08 | int32 | 5C 7F 0C 00 | 0x000C7F5C | level unlock flags for levels 0-31; each level has a corresponding bit:
|
| 0x0C | int32 | 00 00 00 00 | level unlock flags for levels 32-63 | |
| 0x10 | int32 | 00 00 00 00 | level unlock flags for levels 64-95 | |
| 0x14 | int32 | 00 00 00 00 | level unlock flags for levels 96-127 | |
| 0x18 | int32 | 00 00 00 00 | level unlock flags for levels 128-159 | |
| 0x1C | int32 | 00 00 00 00 | level unlock flags for levels 160-191 | |
| 0x20 | int32 | 00 00 00 00 | level unlock flags for levels 192-223 | |
| 0x24 | int32 | 00 00 00 00 | level unlock flags for levels 224-255 | |
| 0x28 | int32 | 01 00 00 00 | 1 | killed Griffin (0 = no, 1 = yes) |
| 0x2C | FE 1B 00 00 | 7166 | unlocked weapons; one bit for each weapon; the number of corresponding bit is given by the skill index value in the primary firing mode block of each ONWC | |
| 0x30 | 1F 00 00 00 | 31 | unlocked items; one bit for each item type (hypo, ammo etc.) | |
| 0x34 | 13 00 00 00 | 19 | last read diary page (level) | |
| 0x38 | 01 00 00 00 | 1 | last read diary page (page) | |
| 0x3C | int32 | 04 00 00 00 | 4 | level of graphical detail; the following options are possible:
|
| 0x40 | float | 00 00 80 3F | 1.0 | sound volume (0.0 = min, 1.0 = max) |
| 0x44 | int32 | 06 00 00 00 | 6 | option flags; the following values are possible:
|
| 0x48 | int32 | 02 00 00 00 | 2 | difficulty; the following values are possible:
|
| 0x4C | int16 | 20 03 | 800 | resolution: width |
| 0x4E | int16 | 02 58 | 600 | resolution: height |
| 0x50 | int16 | 20 00 | 32 | color depth |
| 0x52 | 00 00 | padding | ||
| 0x54 | float | 00 00 00 3F | 0.5 | gamma correction; from 0.0 to 1.0, 0.5 means no correction |
| 0x58 | int32 | 03 00 00 00 | 3 | last saved level |
| 0x5C | int32 | 02 00 00 00 | 3 | last saved save point |
- Killed Griffin
- Used in Chapters 13 and 14; set with killed_griffen, read with did_kill_griffen.
After this header is an array of 400 save points (40 levels, 10 save points per level). The size of a save point is 516 bytes so the array size is 206,400 bytes.
Save point data
| Offset | Type | Raw Hex | Value | Description |
|---|---|---|---|---|
| 0x00 | char[64] | "Save Point 2" | name of the save point in Load Game dialog | |
| 0x40 | int32 | 01 00 00 00 | 1 | valid (was saved previously), i.e. "Should we display this in Load Game?" (0 = no, 1 = yes) |
| 0x44 | int32 | BE 00 00 00 | 190 | current player health (HP) |
| 0x48 | int32 | C8 00 00 00 | 200 | max player health (HP) |
| 0x4C | float | AE 20 FB 43 | 502.255310 | x position of the player |
| 0x50 | float | 03 32 4B 42 | 50.798839 | y position of the player |
| 0x54 | float | 55 12 25 C4 | -660.286437 | z position of the player |
| 0x58 | float | 80 06 C1 3F | 1.508010 | player facing direction (radians) |
| 0x5C | int32 | 00 00 00 00 | 0 | number of ballistic ammo clips |
| 0x60 | int32 | 01 00 00 00 | 1 | number of energy cells |
| 0x64 | int32 | 00 00 00 00 | 0 | shield (percent) |
| 0x68 | int32 | 00 00 00 00 | 0 | invisibility (1/60 seconds) |
| 0x6C | int32 | 01 00 00 00 | 1 | number of hypos |
| 0x70 | int32 | 00 00 00 00 | 0 | door keys |
| 0x74 | int32 | 01 00 00 00 | 1 | whether player has LSI (0 = no, 1 = yes) |
| 0x78 | char[128] | "" | weapon name (unused) | |
| 0xF8 | int32 | 00 00 00 00 | 0 | weapon ammo (unused) |
| 0xFC | char[128] | "" | weapon name (unused) | |
| 0x17C | int32 | 00 00 00 00 | 0 | weapon ammo (unused) |
| 0x180 | char[128] | "w2_sap" | weapon name | |
| 0x200 | int32 | 1E 00 00 00 | 30 | weapon ammo |
- Player health
- Storing both the player's current HP and max HP allows the game to scale your health appropriately if the difficulty level is changed between saving the game and restoring from it.
- Weapon slots
- Yes, Virginia, Oni does seem to support saved data for three weapons, even though the player can only carry one in the final game. Perhaps the three weapon slots were planned to allow for, say, dual-wielded guns and a holstered weapon....