SCUMM: MI (Sega MegaCD) - scrolling should be smooth (also a special cursor while loading data)

[ATMcashpoint]

On a SegaCD emulator, Monkey Island 1 for Sega CD (in English) has smooth, pixel-by-pixel scrolling, rather than the 8-pixels-at-a-time columnar scrolling that SCUMM used from Maniac Mansion until the mid-1990s. However, this isn't reproduced in ScummVM (as of the February 20, 2020 daily build for 64-bit Windows).

Also, the MI1 SegaCD port features a special "wait" cursor while the game is loading data, a watch with a spinning minute hand, which might be desirable to emulate in ScummVM. (It's especially visible during transitions from one screen to anther.)

Oddly enough, both pixel-by-pixel scrolling and special cursors during screen transitions are features that show up also in The DIG.

[AndywinXp]

I am not aware of any version of The Dig showing signs of pixel-by-pixel scrolling: which version are you referring to?

[ATMcashpoint]

All versions of The DIG have pixel-by-pixel scrolling, rather than the 8-pixels-at-a-time scrolling of earlier generations of SCUMM games. Years and years ago it was something ScummVM had trouble with, in fact; in very old builds it would only let the inventory icon scroll in 8-pixel installments, so the icon would bounce around in the lower-left corner of the screen. The speed at which the screen scrolls in The DIG is definitely different natively (I think slower) than in the LucasArts FM Towns games, though.

[dwatteau]

Here's a video showing both the scrolling and cursor effects in Monkey1 SEGA, for reference:

​https://www.youtube.com/watch?v=HERilq6-9JQ&t=2098s

[AndywinXp]

So, here's the thing about the loading cursors: unless it is specifically triggered by the scripts (see COMI when opening the main menu) we can't just add it arbitrarily, by design we virtually don't have loading "zones".

About the scrolling... as far as I know, at the moment nobody on the SCUMM team is familiar with the SEGA CD disasm nor with its technicalities. So it could be a while until this issue can be taken into consideration.

[eriktorbjorn]

We do have smooth scrolling for the FM Towns games, though. I know that FM Towns have their own graphics handling but perhaps the general idea can be extended to cover other games as well? I think think the Amiga ones also should do smooth scrolling?

[ATMcashpoint]

IIRC the Amiga games just had the 8-pixel scrolling that was standard in SCUMM at that time.

[eriktorbjorn]

Replying to ATMcashpoint:

IIRC the Amiga games just had the 8-pixel scrolling that was standard in SCUMM at that time.

I'm not sure. ​https://www.youtube.com/watch?v=W84GMIxOJrw is rather fuzzy, but it looked like smooth scrolling to me. Perhaps there are better videos.

[ATMcashpoint]

You're right, the video in two different MI2 Amiga longplays seems to show that as well:

​https://www.youtube.com/watch?v=Va-ObdSdDoc

​https://www.youtube.com/watch?v=2FRy70XbdCM