Can Sierra SCI games be toggled between VGA/EGA?

[lwc]

Various SCI games had a VGA/EGA setup option that could toggle between VGA Color, VGA Grey and EGA.

Just for comparison with VGA, as ScummVM plays these games in VGA (and in color), is there an option to play them in EGA or for that matter VGA but grey?

It's mentioned in Understanding the graphics settings - Render Mode, but Render Mode seems to offer no options for SCI games.

Example DOSBox screenshots from Lost Secret of the Rainforest (aka EcoQuest 2).

[DarkSoul42]

Just posting a quick finding from SQ5 since the driver selected has implications on gameplay.

A bit of background :

• The rotunda room is room 119, and the messages associated with the dialog box for EGA drivers is the 11th message
• From there, looking at what triggered that dialogue box, one sees it's subject to a flag check (proc0_1 0), i.e the first actual flag in the game!
• Flags are stored in global variable 183 (as checking the code for proc0_1 will show), an array of 16-bit integers, as can be checked from the debug console :

  Code: Select all

  ) vv g 183
  global var 183 == 0000:8000 (32768d)
  

• Luckily since this is the very first flag in the game, it means even with the limited access to the flags variable, it is possible to change it via the debug console by substracting 32768 (aka 2^15, the weight of the most significant bit on a 16-bit integer) :

  Code: Select all

  ) vv g 183 0
  

• Doing the above will cause the game to think it's running on an EGA machine and pop up the skip dialog box.

sq5-debug-EGA-mode.png (59.27 KiB) Viewed 1701 times

This can also be tested from any savegame right after taking the SAT test and before doing the actual cleaning :

Code: Select all

) vv g 183
global var 183 == 0000:d000 (53248d)

) vv g 183 20480

However, while it is possible to disable the flag at the start of the game and progress all the way to the cleaning scene to verify the above without any issue,
saving and reloading will re-enable the flag.