Skill Book Configuration

Tools: Text and configuration editing.

BooksFile names an optional INI file that maps item prototype ids to skills and reading-result messages. sfall adds this configuration to Fallout 2, and Fallout 2 CE implements a compatible subset with some different loader behavior. Vanilla Fallout 2 has five built-in mappings; it does not read this INI itself.

The file changes which items count as skill books. Reading time, consumption, skill gains, and Comprehension remain engine behavior unless separately modified. The details below were checked against sfall's Books.cpp, its distributed books.ini, and Fallout 2 CE on 2026-09-05.

Location and Loading

Set the filename in ddraw.ini:

[Misc]
BooksFile=books.ini

Place books.ini in the game working directory for this example. sfall prepends .\ to the configured name and checks that the file exists. CE opens the configured path with the ordinary filesystem config reader (configRead(..., false)). Neither loader searches DAT archives for this configuration. A file placed only inside master.dat will not supply these settings; an explicit relative subdirectory can be used for a loose file.

An empty filename or unreadable file leaves the vanilla mappings available. CE initializes the registry during item initialization, reads vanilla entries first, then custom entries. Its ordinary item reset does not reread the file. Restart the runtime after changing the configuration rather than expecting a save reload to refresh it.

File Schema

[main]
count=1
overrideVanilla=0

[1]
PID=626
TextID=802
Skill=12

This example registers PID 626 as a Science book and keeps the vanilla books. PID 626 is an example custom item: create or verify that prototype in the target mod before using it. The configuration does not create a PRO or add the item to the player's inventory.

Section	Key	Meaning
`[main]`	`count`	Number of numbered sections to scan, starting with `[1]`. Default 0; values above 50 are limited to 50.
`[main]`	`overrideVanilla`	Default 0 retains the five built-in entries. Nonzero requests a replacement registry, subject to the loader differences below.
`[1]` through `[count]`	`PID`	Full item prototype id, not an FID or a filename. Item PIDs have type byte zero, so ordinary item list ids have the same numeric value.
Numbered section	`TextID`	Reading-result message id in `text\<language>\game\proto.msg`.
Numbered section	`Skill`	Zero-based skill id, `0..17`.

Use plain decimal integers and explicit values for all three entry fields. Section numbering controls the scan; count=2 scans [1] and [2], not the first two sections present in the file. Missing sections do not stop the loop. Sections above the capped count are ignored. At most 50 custom sections are processed; keeping the five vanilla entries can give 55 mappings in total.

CE uses the shared config parser, including semicolon comments and case-insensitive key lookup. sfall uses its own INI reader. The example syntax is suitable for both; do not depend on malformed numeric strings or unspecified fields having identical results.

Vanilla Mappings

Book	PID	Skill id	Skill	TextID in proto.msg
Big Book of Science	73	12	Science	802
Dean's Electronics	76	13	Repair	803
First Aid Book	80	6	First Aid	804
Guns and Bullets	102	0	Small Guns	805
Scout Handbook	86	17	Outdoorsman	806

With overrideVanilla=1, include every vanilla mapping that should remain readable. Removing a mapping removes the default book treatment; it does not remove its prototype or existing instances.

Skill Ids

Id	Skill	Id	Skill
0	Small Guns	9	Lockpick
1	Big Guns	10	Steal
2	Energy Weapons	11	Traps
3	Unarmed	12	Science
4	Melee Weapons	13	Repair
5	Throwing	14	Speech
6	First Aid	15	Barter
7	Doctor	16	Gambling
8	Sneak	17	Outdoorsman

These are skill ids, not SPECIAL stat ids or message ids. The registry supports skills beyond the five vanilla book skills. Choose a result message that describes the configured skill: changing Skill does not automatically change the wording selected by TextID.

sfall and CE Differences

Situation	Inspected sfall loader	Inspected CE loader
Duplicate PID	Searches backward; the last loaded entry wins. Custom entries can replace a retained vanilla mapping.	Searches forward; the first loaded entry wins. A retained vanilla entry shadows a custom duplicate.
Missing PID	Defaults to 0 and skips the entry.	Missing key skips the entry, but an explicit 0 is accepted into the registry.
Missing TextID or Skill	Defaults to 0 for each missing field when PID is nonzero.	Skips the entry if either key is missing.
`count<=0` with replacement requested	Does not install the book hook, so the vanilla handler remains.	Clears the vanilla registry after reading replacement mode, then adds no entries.
Invalid skill or nonexistent prototype	Loader does not validate the reference.	Loader does not validate the reference.

For a replacement that behaves consistently in both, set overrideVanilla=1, use a positive count, include all desired entries, and keep PIDs unique. Do not use an empty replacement file as a portable way to disable all books. Do not rely on an invalid entry to fail safely: in CE, an invalid skill can still lead to reading messages, time advancement, and consumption even though skill increments are rejected.

Reading and Skill Gains

In CE, _protinst_use_item tries book recognition for weapon and miscellaneous item subtypes. Registering an armor, container, or drug PID alone does not route that item through this handler. A custom book also needs usable prototype settings; cloning a working book's PRO is a useful starting point. The configuration supplies no art, name, description, or use-action flags.

The reader operates on gDude: skills, Intelligence, and Comprehension are taken from the player. This is not a companion-training registry.

Outside combat, the algorithm is:

increase = (100 - currentSkillValue) / 10   // integer division
if increase > 0:
    if player has Comprehension:
        increase = (150 * increase) / 100
    repeat increase times:
        skillAddForce(player, skill)
else:
    resultMessage = 801

The current value comes from skillGetValue, including applicable stat, tag, trait, perk, and difficulty modifiers. The gain is computed once before incrementing. Intelligence directly determines reading time and can also indirectly affect the starting value of skills that depend on it.

Comprehension multiplies the already-rounded increment count by 1.5, rounding down again. It is checked as a present/absent perk, not multiplied by its rank. skillAddForce adds one invested skill point per call without spending the player's unspent skill points. Tagged skills double that invested-point contribution in the displayed skill calculation, so increment count is not always the displayed percentage gain.

Starting effective skill	Increment calls	With Comprehension
40	6	9
75	2	3
90	1	1
91	0	0
100 or above	0	0

For an ordinary untagged skill with unchanged modifiers, 75 becomes 77, or 78 with Comprehension. A tagged skill starting at 75 instead gains 4 displayed points, or 6 with Comprehension. The practical cutoff is 91, where integer rounding already produces no gain. This is not a hard post-reading clamp to 100: changes in temporary modifiers can affect the eventual displayed value. The skill increment routine separately checks the general 300 skill limit.

Time, Consumption, and Messages

Reading in combat is rejected with proto.msg id 902. The handler returns without its reading-time advancement or book consumption.

Otherwise reading advances game time by 3600 * (11 - Intelligence) seconds: 10 hours at Intelligence 1, 6 hours at 5, and 1 hour at 10. CE fades the palette, advances time, and executes map update scripts before restoring the palette and displaying the reading messages.

Message id	Use
800	General book-read notification.
Configured TextID	Result notification when the computed gain is positive.
801	Replaces TextID when the computed gain is zero or negative.
902	Reading denied in combat.

All four lookups use proto.msg. The item name and description remain in pro_item.msg through the PRO's message_num; neither those strings nor item.msg supply TextID. A missing reading message is skipped by CE's guarded lookup and does not undo the skill change or time advancement.

The handler returns 1 after reading, even when there was no gain. Its normal caller removes one inventory item and destroys it. Thus an unhelpful book still takes time and is consumed. BooksFile has no key for reusable books, fixed skill gains, a custom cap, or reading duration; those require separate scripting or engine features.

Modding Dependencies

Add the item PRO and its indexed proto\items\items.lst entry; verify subtype, use availability, and art references.
Add its name and description to pro_item.msg, and any custom reading-result text to proto.msg in each supported language.
Register the same PID in the configured loose INI. Use a unique PID or the explicit replacement strategy described above.
Test a low skill, skill 90, skill 91, a tagged skill, Comprehension, and attempted reading during combat. Check inventory quantity and elapsed time as well as displayed text.

The registry is startup configuration rather than a save-slot book-definition file. Existing inventory objects still carry their PIDs, so changing the registry can change how those objects behave in an existing save after restarting. Already-earned skill points are not rolled back when a mapping changes.

Sources

sfall distributed books.ini: supported fields and intended vanilla override behavior.
sfall Books.cpp: filesystem path, 50-entry limit, defaults, backward lookup, and hook installation.
Fallout 2 CE item.cc: booksInitVanilla, booksInitCustom, and booksGetInfo.
Fallout 2 CE proto_instance.cc: _obj_use_book, _protinst_use_item, and _obj_use_item.
Fallout 2 CE skill.cc: skillGetValue and skillAddForce.
Fallout 2 CE config.cc: filesystem versus database config reading.