Opened 18 years ago

Last modified 3 years ago

#2693 new defect

SCUMM: Potential savegame incompatibility

Reported by: eriktorbjorn Owned by:
Priority: normal Component: Engine: SCUMM
Version: Keywords:
Cc: Game: Indiana Jones 3


I've only tested this bug with the latest SVN and the VGA version of Indy 3, but it should be reproducable in a couple of other games.

If I run the game using the Adlib music driver, _imuse is created (even though the game does not really use iMUSE), and when I save a game, the iMUSE state is saved in it.

If I run the game using the PCjr music driver, _imuse is not created (since the PC speaker drivers are not played through iMUSE). But when I try to load the previously created savegame, the iMUSE state is not skipped. So the data is read back to the wrong variables. Most noticeably (and probably least seriously), the mouse cursor is corrupted.

Ticket imported from: #1508095. Ticket imported from: bugs/2693.

Change History (7)

comment:1 by Kirben, 18 years ago

The original versions of SCUMM 3 - 4 games, would check the value of VAR_SOUNDCARD when loading a saved game, to make sure it matched current sound driver. And reject the saved game, if it didn't match.

We can either add dummy data for imuse to saved games, when it isn't active in these games. Although there could be unusal side effects when sound card drivers are changed in some situations.

Or limit saved games in these games, to the specific sound card driver used, when game was saved, like original versions.

comment:2 by sev-, 18 years ago

Since we have all 'soundcards' in-place, I would consider another route: give user a warning and force sound driver change, i.e. something like this:

"This save was written with PC-Speaker sound driver. Current driver is Adlib. Forcing PC-Speakier driver"

comment:3 by lordhoto, 18 years ago

I would prefer to keep the possibilty to switch the sound driver while playing so you are able to use the same savegame once with PC-Speaker and another time with AdLib. It's much nicer than restricting a savegame to a specific music driver.

comment:4 by fingolfin, 16 years ago

See also the (now closed) bug report #1804278 (Monkey) and #1752196 (in FOA).

In both cases, there are problems with missing/garbled cursor data. In the second bug I quote, there are 714 bytes of extra data *after* the iMuse data and before the cursor data, and I have no idea why...

comment:5 by sev-, 7 years ago

Component: --Unset--Engine: SCUMM

comment:6 by digitall, 5 years ago

Game: Indiana Jones 3

comment:7 by tag2015, 3 years ago

Issue still present in ScummVM 2.3.0git19249-ge41aec4cb4

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