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PSTEE Engine Quirks

AquadrizztAquadrizzt Member Posts: 1,037
edited November 24 in PST:EE Mods
As I work on my various Planescape mods, I come across pieces of information about the functionality of the engine. Here are some interesting things I have discovered
  • Unused Opcodes That Work: Timestop, Use Any Item
  • Unused Opcodes That Don't Work: Find Traps, Improved Alacrity, Haste, Create Magical Weapon, Fist Thac0 Bonus, Fist Damage Bonus, Modify Visual Range
  • The engine does support the addition of new Mage and Priest spells as long as you remember to ADD_SPELL_EX them and update spells.2da.
  • Projectiles in PSTEE are hardcoded, despite having Weidu/NI accessible files.
  • The trigger condition for items in store files (offset 0x001c in the Items for Sale extended header) cannot contain an Or() statement.
  • The store interface will place conditionally available items above unconditionally available items. The order of these within the .sto file is respected within these two groups.

I'm curious to see what interesting engine behavior other people have found.
Post edited by Aquadrizzt on


  • argent77argent77 Member Posts: 3,221
    PST:EE does not support any weather effects, including fog.

    The SpellCast*() triggers don't seem to work in PST:EE, which includes
    0x0091 SpellCast(O:Object*,I:Spell*Spell)
    0x0091 SpellCastRES(S:Spell*,O:Object*)
    0x00a6 SpellCastPriest(O:Object*,I:Spell*Spell)
    0x00a6 SpellCastPriestRES(S:Spell*,O:Object*)
    0x00a7 SpellCastInnate(O:Object*,I:Spell*Spell)
    0x00a7 SpellCastInnateRES(S:Spell*,O:Object*)
    0x00a1 SpellCastOnMe(O:Caster*,I:Spell*Spell)
    0x00a1 SpellCastOnMeRES(S:Spell*,O:Caster*)
  • AquadrizztAquadrizzt Member Posts: 1,037
    edited November 24
    The Blindness opcode (78) only applies the AC penalty. It has no discernible effect on THAC0 or visual range.
  • AquadrizztAquadrizzt Member Posts: 1,037
    edited November 26
    A damage effect (Opcode 12) that permits a save will always be "save for half damage".

    You can avoid this by having the damage effect applied via a sub resource and having the save be placed on the 177/326 effect that applies the sub resource.
  • AquadrizztAquadrizzt Member Posts: 1,037
    Invisibility (opcode 20) does not care about the parameter1 value that determines whether it's normal or improved.

    All invisibility is removed upon attack.
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