Scummvm, crt tv 15Khz, SDL1.2 and SDL2

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quartex73
Posts: 2
Joined: Thu Jul 15, 2021 12:23 am

Scummvm, crt tv 15Khz, SDL1.2 and SDL2

Post by quartex73 »

Hi all.
I'm using scummvm on a crt tv 15Khz using a compatible analog ati card and calamity crtemudriver. I'm very satisfied because I can use original 320x200 resolution.
This happens using scummvm 1.8.1 (the last using SDL 1.2).
When trying releases using SDL2 result is not the same.

Looking this post:
viewtopic.php?f=2&t=14527

I noticed this:
"it seems that SCUMMVM doesn't change the display resolution, it sticks to the desktop resolution and only changes its internal resolution."
"That is correct when ScummVM uses SDL2 (as opposed to SDL 1.2) which is the case in the last release for most platforms (including Windows, macOS, Linux) I believe, and when not using the OpenGL mode. In such a case SDL2 indeed keeps the desktop resolution in fullscreen mode and scales internally the data it gets from ScummVM."

So correct me if I'm wrong... With my setup using SDL2 I will never experience same result as using SDL1.2?

Thanks in advance for your reply
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rootfather
ScummVM Lead
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Re: Scummvm, crt tv 15Khz, SDL1.2 and SDL2

Post by rootfather »

With SDL2, your setup is not possible indeed, since SDL2's full-screen mode always takes the current desktop resolution and doesn't do any resolution-switching on its own.

The only way to solve this with SDL2 is to somehow trick your Windows installation to use a 320x200 resolution. You _could_ try the OpenGL mode, but as far as I know, it behaves exactly the same as the SDL2 renderer.

Sorry :(
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criezy
ScummVM Developer
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Joined: Sat Sep 23, 2006 10:41 am
Location: West Sussex, UK

Re: Scummvm, crt tv 15Khz, SDL1.2 and SDL2

Post by criezy »

For OpenGL, the change to use the desktop resolution in fullscreen was made a few months ago as part of the changes to support High-DPI screens. This means that the last release (version 2.2.0), which predates those changes can still change the screen resolution in fullscreen mode. You can use the CTRL ALT +/- to cycle through the supported resolutions.
quartex73
Posts: 2
Joined: Thu Jul 15, 2021 12:23 am

Re: Scummvm, crt tv 15Khz, SDL1.2 and SDL2

Post by quartex73 »

I already tried opengl and I noticed no difference with sdl2. The resolution size is correct (for example 320x200) but image is not sharp, there is a sort of blurring effect (I suppose because my desktop use 640x480 interlaced). This happens with every release higher than 1.8.1
Am I missing something?
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