SPL file format

Applies to:
BG1, BG1: TotS, BG2, BG2: ToB, PST, IWD, IWD:HoW, IWD:TotL, BGEE

General Description
This file format describes a "spell". Spells include mage spells, priest spells, innate abilities, special abilities and effects used for game advancement (e.g. animation effects, custom spells). SPL files have a similar structure to ITM files.

Header:Size=114 Bytes Ext. Header: Size= 40 Bytes Feature Block: Size=48 Bytes

Detailed Description
SPL files consist of a main header, zero or more extended headers (each containing zero or more feature blocks) and zero or more casting feature blocks. All the feature blocks are stored as a continuous data segment, with each extended header containing an offset into this data, and the main header containing an offset into this data for the casting feature blocks.

Overall structure:


Offset Size (datatype) Description
0x0000 4 (char array)

Signature (‘SPL  ’)

0x0004 4 (char array)

Version (‘V1 ‘)

0x0008 4 (dword)

Spell Name - Unidentified (strref)

0x000c 4 (dword)

Spell Name - Identified (strref) (usually -1)

0x0010 8 (resref)

Completion Sound

0x0018 4 (dword)

Flags

0x001c 2 (word)

Spell type:

  • 0 = Special
  • 1 = Wizard
  • 2 = Cleric
  • 3 = Psionic
  • 4 = Innate
  • 5 = Bardsong
0x001e 4 (dword)

Exclusion Flags

0x0022 2 (word)

Casting Graphics

0x0025 1 (byte)

Primary Type (Spell school) (IWD: school.2da, BG2:mschool.2da)

0x0027 1 (char)

Secondary Type (BG2:msectype.2da)

0x0034 4 (dword)

Spell Level

0x003a 8 (resref)

Spellbook icon (BAM). The engine replaces the last character of this filename with a C.

0x0050 4 (dword)

Spell Description - Unidentified (strref)

0x0054 4 (dword)

Spell Description - Identified (strref) (usually -1)

0x0064 4 (dword)

Extended Header offset

0x0068 2 (word)

Extended Header count

0x006a 4 (dword)

Feature Block Table offset

0x006e 2 (word)

Casting Feature Block offset (these feature blocks may not use target type 2)

0x0070 2 (word)

Casting Feature Block count



Extended headers represent the effects of a spell on the target. Multiple extended headers can be set in a spell, to allow the spell to use effects based on the level of the caster. Extended headers should be in the file in order of increasing level

Offset Size (datatype) Description
0x0000 1 (char)

Spell form

  • 1 - Standard
  • 2 - Projectile
0x0001 1 (char)
  • bit 2: ‘Friendly’ ability
0x0002 2 (word)

Location

0x0004 8 (resref)

Memorised icon (BAM). The engine replaces the last character of this filename with a B.

0x000c 1 (char)

Target:

  • 0 = Invalid (target cannot be selected)
  • 1 = Creature
  • 2 = Crash
  • 3 = Character potrait (ignores range, uses projectile #1)
  • 4 = Area
  • 5 = Self
  • 6 = Crash
  • 7 = None (Self, ignores game pause)
0x000d 1 (char)

Target Number

0x000e 2 (word)

Range

0x0010 2 (word)

Level Required

0x0012 2 (word)

Casting Time

0x0014 2 (word)

Times per day

0x001e 2 (word)

Count of feature blocks

0x0020 2 (word)

Offset to feature blocks

0x0026 2 (word)

Projectile (BG2: projectl.ids. Note: in BG2, this value is off-by-one from projectl.ids value. I.e. binary value of 2 corresponds to 0x1 - ARROW)



Any action carried out by a spell is done by feature blocks, each of which holds an effect number as well as targetting and timing information. The engine appears to roll a probability for each valid target type, rather than one probability per attack.

Offset Size (datatype) Description
0x0000 2 (word)

Opcode Number

0x0002 1 (char)

Target type

  • 0 = None
  • 1 = Self (pre-projectile)
  • 2 = Pre-target
  • 3 = Party
  • 4 = Everyone (inc. party)
  • 5 = Everyone (excl. party)
  • 6 = Everyone matching specific value of caster (or Party if cast by party member)
  • 7 = Everyone matching specific value of target (In ITM: ranged ability type only, otherwise no target)
  • 8 = Everyone (excl. caster)
  • 9 = Self (post-projectile)
0x0003 1 (char)

Power

0x0004 4 (dword)

Parameter 1

0x0008 4 (dword)

Parameter 2

0x000c 1 (char)

Timing Mode

  • 0 = Duration
  • 1 = Permanent
  • 2 = While equipped
  • 3 = Delayed Duration
  • 4 = Delayed
  • 5 = Delayed (transforms to 8)
  • 6 = Duration?
  • 7 = Permanent?
  • 8 = Permanent (unsaved)
  • 9 = Permanent (after Death)
  • 10 = Trigger
  • 4096 = Absolute duration

NB. all effects except those with Timing mode ‘9’ are removed by death.

0x000d 1 (char)

Resistance

The default behaviour is that effects cannot be dispelled and ignore magic resistance.

  • bit 0: Can be dispelled, affected by magic resistance
  • bit 1: Ignores magic resistance (when used in combination with bit 0)
  • bit 2: Bypasses deflection/reflection/trap opcodes (only in EE games patched to v2.0+ / external EFF files)
  • bit 31: Effect was applied by an ITM (only present in EE games patched to v2.0+ / external EFF files). It is set by the engine if the effect’s source ITM is identified. This bit is only used by opcode #324 which checks it to determine whether it should set STRREF_FEEDBACK_IMMUNE_RESOURCE (see ENGINEST.2DA) to the ITM’s general or identified name

The only difference between 0 and 2 is that 0 will automatically convert to 2 when targeting yourself.

This can also be presented in the more traditional way:

  • 0 = Natural/Nonmagical
  • 1 = Can be dispelled/Affected by resistance
  • 2 = Cannot be dispelled/Ignores resistance
  • 3 = Can be dispelled/Ignores resistance
0x000e 4 (dword)

Duration

0x0012 1 (char)

Probability 1

0x0013 1 (char)

Probability 2

Note: The BG1 engine treats probability as a single word, effects are applied in the range 0-probability.
Note: Other engines treat probability as two values, effects are applied in the range probability <= x <= probability.
Probability range is 0-99

0x0014 8 (resref)

Resource

0x001c 4 (dword)

Dice Thrown

0x0020 4 (dword)

Dice Sides

0x0024 4 (dword)

Saving Throw Type

  • bit 0: Spells
  • bit 1: Breathe
  • bit 2: Death
  • bit 3: Wands
  • bit 4: Polymorph
  • bit 10: Ignore primary target – Line AoE projectile doesn’t affect end target (EE only)
  • bit 11: Ignore secondary target – Line AoE projectile doesn’t affect bystanders (EE only)
  • bit 24: Bypass mirror image (EE/TobEx only)
  • bit 25: EE - ignore difficulty; TobEx - limit effect stacking
  • bit 26: TobEx internal (don’t use) - suspend effect application

NB. If more than 1 saving throw type is specified, the target rolls against their best save.

0x0028 4 (dword)

Saving Throw Bonus

0x002c 4 (dword)

TobEx: Stacking ID. Checked when bit 25 of the Saving Throw Type is set.

If two effects of the same opcode are applied, both have Limit Effect Stacking bit set, and both have the same stacking ID, then the latter applied effect is suspended in application until the former effect expires. Regardless of whether it is applied, the latter effect will expire at the same time that it would expire if it was applied. In other words, the total duration of some non-stacking effect opcode is not extended because more than one copy of the effect was applied.

Stacking IDs are unique to the opcode being applied. To maintain uniqueness of stacking IDs between different mods, one recommendation is to use the higher word of Special as the modder’s Infinity Engine Community Prefix, then use the lower word as an identifying ID. For example, 0x41360001 (‘A6’ 0x0001).





Bit Byte 1 Byte 2 Byte 3 Byte 4
0 Unknown Unknown Not in combat Can target invisible (BGEE, TobEx)
1 Unknown Breaks Sanctuary (BGEE) Unknown Castable when silenced (BGEE, TobEx)
2 Unknown Hostile/Breaks Invisibility Unknown Unknown
3 Unknown No LOS required Unknown Unknown
4 Unknown Allow spotting Unknown Unknown
5 Unknown Outdoors only Unknown Unknown
6 Unknown Ignore dead-magic and wild surge effect Unknown Unknown
7 Unknown Ignore wild surge effect (i.e. trigger/contingency) Unknown Unknown


bit 0: Exclude Chaotic priests. (BG2 & HoW)
bit 1: Exclude Evil priests. (BG2 & HoW)
bit 2: Exclude Good priests. (BG2 & HoW)
bit 3: Exclude GENeutral priests. (BG2 & HoW)
bit 4: Exclude Lawful priests. (BG2 & HoW)
bit 5: Exclude LCNeutral priests. (BG2 & HoW)
bit 6: Exclude Abjurers
bit 7: Exclude Conjurers
bit 8: Exclude Diviners
bit 9: Exclude Enchanters
bit 10: Exclude Illusionists
bit 11: Exclude Invokers
bit 12: Exclude Necromancers
bit 13: Exclude Transmuters
bit 14: Wild Magic (exclude Generalists) (BG2)
bit 15 - 29: Unused
bit 30: Exclude Cleric/Paladin
bit 31: Exclude Druid/Ranger

NB.Alignment and School exclusion bits cannot be combined.


BG1,BG2,IWD
00
    ...No animation
08
09 Necromancy
10 Alteration
11 Enchantment
12 Abjuration
13 Illusion
14 Conjuration
15 Invocation
16 Divination
17 White sparks
18 Black sparks
19 White sparks
20 White sparks
21 White sparks
22 White -> red sparks
23 White -> purple/red sparks
24 White -> red sparks
26 White sparks
32 White sparks
34 White sparks
56461 No animation
65535 No animation

NB. The 'spark' entries are related to sprklclr.2da (and probably opcode #41)

PST
35: Abjuration
36: Alteration
37: Conjuration
38: Enchantment
39: Divination
40: Illusion
41: Invocation
42: Necromancy
44: Special (Innate) Skill