Phantasmagoria 2 - flashing screen problem

[almeath]

I tried running the Windows 95 version of "Phantasmagoria: A Puzzle of Flesh" in ScummVM 2.8.0 on Windows 11 23H2.

I noticed that in-between every video that is played (when in full screen mode) the screen flashes quickly between showing the Windows desktop, a black screen, and then the video.

As a point of comparison, when running the GOG release of the same game (using what appears to be an old ScummVM 2.0 build) this problem does not occur.

If I replace the GOG version's ScummVM folder with the ScummVM 2.8.0 folder, the game launches but the same flashing screen issue starts to occur again.

So it appears to be a problem specific to ScummVM 2.8.x.

I tried the latest DEV release and stable 2.8.x build and the same issue occurs.

Not sure if this is a known issue and/or affecting other FMV games?

UPDATE: I tried ScummVM 2.7 and the same issue occurred. I then switched to SDL mode in full screen and that fixed the issue. However, it is not really a fix because I wanted to use OpenGL shader support, which is not available in SDL mode. The problem is with the OpenGL graphic mode.

[almeath]

As an addendum, I found that basically every game that starts in full screen in "OpenGL" mode flashes back-and-forth to some extent, some worse than others, but only while launching. Most games settle down after that and there is no further issue. The problem with some FMV games such as Phantasmagoria 2, is that each time the game switches from the normal game environment to the FMV video sequence, it is doing something similar to a game 'launch', hence the flashing.

I suppose this is an underlying issue with the implementation of OpenGL and cannot be helped at this stage? I would use SDL, but as mentioned, I would have to forgo use of shaders which I have found to be very useful.

[criezy]

I suspect the flashing happens when switching between different graphics modes, for example if videos sequences and game screens use a different resolution. So not all FMV games would be impacted, and some non/FMV games (such as Dreamweb) would be impacted as well.

[almeath]

I am uncertain if it is worth reporting as a bug then. I do not understand enough about it, to determine if it is inherent to OpenGL being used as a graphic mode in Windows. However, I do not recall it affecting the same mode in MacOS.