The real reason you got that machine (or emulator), right? Classic and new Amiga games talked about here. Have you seen the Games Library?
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Shot97
Detroit, MI, USA

by Shot97 posted Sat Apr 16, 2016 7:57 am

My modern monitor is a 1920x1080 Acer. My monitor for DOS is a Dell monitor made by Trinitron, it is a flat CRT. IMO one of the best monitors ever made. Of course taking a picture of any CRT is not perfect, but I'd sooner populate the internet with those pictures than of any screenshots. I can flat out tell you 100% what I see on the CRT picture is closer to reality than ANY of those screenshots. It's all about compromise when you're dealing with strange resolutions that were designed to be stretched. While my CRT shots may not be perfect, I'd have no problem what so ever as those being regarded as history compared to any of those screenshots.
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PhilsComputerLab

by PhilsComputerLab posted Sun May 01, 2016 7:27 am

So I pulled out the Mist FPGA computer again and working on a video review of the Amiga core :)

Having lots of fun with classics such as Lemmings, Stunt Car Racer, Alien Breed and Turrican 2.

The Mist outputs VGA and on the CRT, oh my, it looks lovely.

Something I notices though, pretty much EVERY game has the image at a different position and / or size. That surprised me and because I'm using the Mist I don't know if this is also on the real thing.

In Alien Breed for example, it doesn't look right if the image is adjusted to 4:3, it looks right if it's even taller (imagine a 4:3 image and then you make it taller). At 4:3 the head has different shape when walking horizontally vs vertically.

What does everyone think?

EDIT: Something else. In many games, the width of the screen changes depending on the content. For example in Shadow of the Beast the game is thinner compared to the intro screens :)

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intric8
Seattle, WA, USA

by intric8 posted Mon May 02, 2016 9:59 am

@Phill I'm not familiar with the MIST board. I went and looked it up and it sounds pretty sweet. That being said, it does seem to have some "limitations". The first being that you can't bump down to OCS for pre-1990 games. Maybe not the end of the world, but there's that. E.g. Archon is probably a fail. ECS usually does just fine, but every now in then you might run into a gotcha.

But then I got to wondering about the VGA graphics that come with MIST, pertaining to your original question. I can't help but wonder if what you are seeing is some sort of artifact of the graphics conversion. By default Amiga computers were not VGA, they had proprietary RGB video out - although you can get adapters for them to work with VGA monitors. But a simple adapter wouldn't account for the frequency differences. I wonder if what you're seeing has something to do with that.

I would double check that your monitor can accept the signal (50 or 60 MHz) first. Gotta be something with the hardware setup, IMO.

To speed things up, I would shoot off an email to till@harbaum.org, who is the contact on the MIST site. Shoot him the post link to save time. He might be able to help.
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PhilsComputerLab

by PhilsComputerLab posted Mon May 02, 2016 3:37 pm

Of course the Mist supports OCS.

Any way, forget about the Mist, my question was really about the position and size of the image in various games and even in games.

Does it change for you for most games? Meaning some games are taller than others, some are wider than others, some are lower than others and one needs to adjust the Amiga monitor for most games?
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intric8
Seattle, WA, USA

by intric8 posted Mon May 02, 2016 4:00 pm

That's a really interesting question.

I would have to say that, in general, no, things don't shift around. However, it's not that simple of an answer. Some games - by design - have black bars for UI reasons. Usually, however, it is on the bottom. And many times, while it seems like wasted space, it's often there for the occasional UI element to appear when needed (seems strange today for such a design choice to be made, but it must have been easier back then to simply allocate areas like that).

Here's an example - if you look at Loom, scroll to the bottom where the screenshots are. You'll see many have a giant black bar down there, and at first glance it seems almost broken. And you go through the game for quite some time before you realize that space is actually reserved for other UI elements (e.g. see the last screenshot).

However, it is worth noting that in emulation I've seen shifting occur and I couldn't explain it. I only learned how to avoid it. Example: I loaded a game over the weekend in emulation and manually set it to NTSC. I knew it was a game targeted to N. America so set it up myself. However, on launch, I noticed over time that top of the screen was being cropped by about 10-20 pixels. Just enough to chop a very short slice off the top. I've seen this in 3 separate instances.

If I were on my A1200, I could reach behind the 1084S monitor and use one of the vertical control knobs to fix that problem very easily. The only way I could fix it in software was to tell the emulator to 'Auto' select PAL/NTSC and resolution for me. Ultimately it chose NTSC, but the cropping didn't occur. Makes no sense!

I've never seen any left/right anomalies, only vertical.

EDIT: I only made the OCS assumption because one of the retailers said it supported "ECS, AGA" among several other technologies and platforms. I assumed (incorrectly) that the omission of OCS was intentional.
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PhilsComputerLab

by PhilsComputerLab posted Mon May 02, 2016 4:28 pm

Cool, that makes sense!

I remember having similar issues with the first PlayStation and Scart RGB. Every game had a slightly different position.

On a CM 8833 that's easy to address. I later got a Sony Trinitron TV and used the service menu for those adjustments :)
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PhilsComputerLab

by PhilsComputerLab posted Tue May 03, 2016 5:41 am

Here the Mist playing Gods on a PC CRT screen. I wonder how it compares to a CM 8833 or similar monitor?

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intric8
Seattle, WA, USA

by intric8 posted Tue May 03, 2016 9:36 am

That looks pretty danged good if you ask me.
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Shot97
Detroit, MI, USA

by Shot97 posted Tue May 03, 2016 11:26 am

I looked into Alien Breed finally. Sorry, haven't been feeling too good recently and I'm way behind on stuff. Upon taking a screenshot from the actual hardware this is what I get:

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The above picture is NOT a 4:3 image. It does look taller than wide. If I manually crop it into 4:3 this what I get:

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As you can see the text areas are perfectly cut off. In this instance I would say the game may have used PAL overscan mode. Given that this game bypassing AmigaDOS I can't take a screenshot directly from the computer to prove this, but it would be my guess. Everyone's thoughts?
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Shot97
Detroit, MI, USA

by Shot97 posted Tue May 03, 2016 11:36 am

A game like Shadow of the Beast I believe used HAM mode (4096 colors) for some of the still pictures. Sometimes sloppily designed European games would feature title screens in PAL 320x256 mode but the actual game would be in NTSC resolution of 320x200. This was done to more easily port the European game to America, but it's a sloppy design through and through because plenty of games (like Pinball Dreams) which were in full 320x256 PAL mode were successfully converted to NTSC 320x200 looking perfect. Just lazy design. World Circuit/F1GP has one picture in PAL mode but the rest of the game and pictures are in NTSC mode. The Amiga had many graphics modes including special overscan modes for all resolutions including HAM which would allow even more content to be displayed if wanted. Some games switch between them many times, usually not noticed because of the use of emulators, where a screenshot wouldn't help you anyway.

More things to keep in mind when taking screenshots.... In the instance of Alien Breed you'd have to delve into the overscan resolutions and figure out the formula there if screenshoted... This stuff can get complicated, huh? Daaahhhh... Let's all just take pictures of the CRT and call it a day! ha!

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