EEex to the rescue

[sgunciner]

Hi, first of all thanks for the amazing EEex,

I have been on to an issue in enhanced editions I believe EEex may help fix. It is a variable corruption regarding clones and spell books.
To see the issue on a debug level, open you UI.MENU file, find "name 'MAGE'" line where the spell book menu resides and add these lines to the onOpen section:

local charId = 'EEex ID:' .. EEex_Sprite_GetSelectedID() .. ', Engine ID:' .. id
C:DisplayText(charId)

After that boot the game with EEex. To see the issue clearly enable auto-pause on spell cast (not a must but makes the issue consistent).

Use a mage character preferably (all casters have the issue but not as pronounced as a mage). Cast "Simulacrum" (or Mislead). Now select your original PC not your clone and open your spell book. You will see EEex ID and Engine ID values are different and voila you are seeing the spell book of your clone.

Even if you don't use auto-pause, this issue crops up randomly when you open your spell book. One second you get your clones id and its spell book another you are seeing the correct one. When beamdog fixed clones losing their names and items after save, or during new ui integration I can't say clearly, they cause this issue where clone id poisons the original character id. If there's a way to update engine's id value with EEex_Sprite_GetSelectedID somehow on spell book open for example, issue would be fixed I guess. Classic versions don't have this issue btw.

It would be great if you can confirm this and offer a solution. Thanks in advance.

[MephistoSatanDevil]

Speaking of which, I recall a question: Could the bug where Hexxat's coffin can be taken out of Dragomir's Respite be more elegantly fixed using EEex?

[Bubb13]

Ok, this is weird. Wall of text incoming so I can remember what to fix later.

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Relevant values are set by:

• CGameEffectPuppetMaster::ApplyEffect() (op237) - This is applied by op236 to the clone if param2 was 1 (Mislead), 2 (Project Image), or 3 (Simulacrum).

  On tick it sets:

  • CDerivedStatsTemplate::m_nPuppetId on the puppet master.
  • CDerivedStatsTemplate::m_nPuppetMasterId on the puppet.
  • CDerivedStatsTemplate::m_nPuppetMasterType on the puppet.

• CGameSprite::CheckPuppetMaster() - This runs on the puppet every AI tick.

  It maintains:

  • CDerivedStatsTemplate::m_nPuppetId on the puppet master (only for "Project Image" clones).
  • CDerivedStatsTemplate::m_nPuppetType on the puppet master.

CDerivedStatsTemplate::m_nPuppetId used by:

• CGameEffectDamage::ApplyEffect() - Checks CDerivedStatsTemplate::m_nPuppetType and CDerivedStatsTemplate::m_nPuppetId to see whether the hit creature has a "Project Image" clone. On match it removes the clone from the area.

• CScreenWizSpell::DoneSequencingSpells() - Overrides which object id it applies the sequencer-maintaining effects to with CDerivedStatsTemplate::m_nPuppetId if it is not -1.

• CScreenWizSpell::GetSelectedCharacterObject() - Used all over the wizard spell book. Overrides which object id returns if CDerivedStatsTemplate::m_nPuppetId is not -1 on the usually-returned object.

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So, surprisingly, the mentioned behavior seems "intentional" in the sense that there's code specifically backing it. The implementation is super buggy though:

1. CDerivedStatsTemplate::m_nPuppetId is only reliably maintained for "Project Image" clones via CGameSprite::CheckPuppetMaster().

   CGameEffectPuppetMaster::ApplyEffect() attempts to maintain CDerivedStatsTemplate::m_nPuppetId on the puppet master, but since this effect is ticked on the clone it's completely desynced from the puppet master's derived stats. Every time the puppet master evaluates its effect list its CDerivedStatsTemplate::m_nPuppetId value is cleared, leaving the value as -1 until the puppet also reevaluates its effect list.

   All overrides relying on CDerivedStatsTemplate::m_nPuppetId are flaky and only apply intermittently due to this buggy method of maintaining the value.

2. Overriding the wizard spell book to work with the puppet is strange. It prevents managing the puppet master's book while the clone is active, and the CScreenWizSpell::DoneSequencingSpells() override means casting a contingency / sequencer as the puppet master sets the contingency / sequencer up on the clone. These spells don't work at all when cast by clones.

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EEex should disable the wizard spell book overrides that are based on CDerivedStatsTemplate::m_nPuppetId.

It might also be worthwhile to fix how CDerivedStatsTemplate::m_nPuppetId is only intermittently maintained by removing the "Project Image" clone-type requirement in CGameSprite::CheckPuppetMaster(). This would only be useful for mods that target the PUPPETID stat.

[sgunciner]

Wow man, great to see the inner workings of the issue laid bare. Being a technical artist myself, must say this is an impressive art :)