[Scummvm-tracker] [ScummVM] #10773: QFG4 floppy: Crash when asking Cranium for potions

[Vhati]

#10773: QFG4 floppy: Crash when asking Cranium for potions
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  Reporter:  Vhati              |      Owner:  (none)
      Type:  defect             |     Status:  new
  Priority:  high               |  Component:  Engine: SCI
Resolution:                     |   Keywords:  SCI32
      Game:  Quest for Glory 4  |
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Comment (by Vhati):

 Both error addresses above (00bb:03a6 and 00f2:03a6), in their respective
 savegames, refer to craniumThumbs.

 Script 69 delares craniumTalker, whose showAgain() is calling
 craniumThumbs::show(). At that moment, craniumThumbs has no valid plane to
 be drawn on. While chatting prior to the formula prompt, plane had been
 0012:0003.

 During a chat, I can toggle his visibility in the debugger without issue
 ("send craniumTalker hide" and "send craniumTalker showAgain"). The
 transition to the formula prompt, and back, must be removing Views from
 the plane, and not putting them back.

 Just before the prompt, "bp_kernel DeleteScreenItem break" says
 craniumTalker is getting disposed.

 See also: #10778 where hero's visibiliy wasn't getting restored as the
 room was disposed.

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Ticket URL: <https://bugs.scummvm.org/ticket/10773#comment:6>
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