Opened 3 years ago

Last modified 5 months ago

#9967 new defect

SCUMM: Zak McKracken (FM-Towns) shows no graphics in windowed mode (OpenGL/RGB555)

Reported by: angstsmurf Owned by:
Priority: normal Component: Graphics
Keywords: FM-Towns Cc:
Game: Zak McKracken


Unlike #9945 and #9946, this happens in the nighly builds using SDL 1.2.14 as well: when using OpenGL graphics windowed mode, Zak McKracken FM Towns version (the one available from GOG) will only show a black screen, though the sound is working. Fullscreen works fine.

ScummVM 1.10.0git3962-g850dcdbdf8 and MacOS Sierra 10.12.5, on a Retina MacBook
Pro, 15 inch, mid 2014.

Change History (17)

comment:1 by angstsmurf, 3 years ago

I just tested this again with the latest build and SDL2 2-0-6, and now the screen is black when starting in fullscreen as well. Still works fine with any non-OpenGL mode.

comment:2 by csnover, 3 years ago

Does this happen with any other game, or is it only the FM Towns Zak McKracken?

comment:3 by angstsmurf, 3 years ago

It happens in FM Towns Loom as well. I'll keep checking.

EDIT: And now it happens in full screen mode as well.

Last edited 3 years ago by angstsmurf (previous) (diff)

comment:4 by angstsmurf, 3 years ago

… which means that the title should be changed, I suppose.

comment:5 by csnover, 3 years ago

I’m not able to reproduce this issue on rMBP mid-2012, macOS 10.12.6, SDL 2.0.6, OpenGL mode, filtering on or off, using the discrete (Nvidia) GPU. Do any games render using OpenGL mode for you? Do they work if you switch between integrated/discrete GPU?

comment:6 by angstsmurf, 3 years ago

I only have an integrated GPU (Intel Iris Pro) in this machine. Black screen on all Lucasarts FM Towns games in OpenGL mode, and only on those. Fine in all non-OpenGL modes.

comment:7 by csnover, 3 years ago

Yes, but what about games that are not FM-Towns?

comment:8 by angstsmurf, 3 years ago

All fine.

comment:9 by angstsmurf, 3 years ago

Happens in official 1.9.0 build as well.

comment:10 by csnover, 3 years ago

OK, so I guess what is probably happening here is that the GPU doesn’t support RGB555, which is the mode used by FM Towns. I’m unfamiliar with GPU programming so I’m not sure what options exist here yet to allow this to work (other than to convert in software, which is what SDL already does when you use the normal renderer). I’ll do some research when I have time, if someone else with the prerequisite knowledge doesn’t pipe in first with an answer.

comment:11 by angstsmurf, 3 years ago

Thanks for looking into this! I'll just assume that I was mistaken all along about that "in windowed mode" part, it really makes no sense.

comment:12 by digitall, 2 years ago

Component: --Unset----Other--

comment:13 by ccawley2011, 15 months ago

Component: --Other--Graphics

Is this issue still present?

comment:14 by angstsmurf, 15 months ago

I'm afraid I don't have access to that computer anymore, and my current one does support RGB555, but I suppose there are plenty of other computers out there using the same integrated GPU that could check this.

comment:15 by digitall, 15 months ago

Game: Zak McKracken
Keywords: FM-Towns added

comment:16 by angstsmurf, 15 months ago

And as mentioned above, this applies to all FM-Towns games, and not only in windowed mode, but in OpenGL, windowed or fullscreen, so the title is misleading. I don't know if other ScummVM games use RGB555, but if so, it applies to them too. The problem is with GPUs that don't support that mode.

comment:17 by raziel-, 5 months ago

Summary: OPENGL: FM Towns Zak McKracken shows no graphics in windowed modeSCUMM: Zak McKracken (FM-Towns) shows no graphics in windowed mode (OpenGL/RGB555)
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