Source ports vs. emulation

Discuss classic PC games
developertn
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God, Jesus Christ, is number one!hehe

Post by developertn »

Jesus Christ!hehe

For obvious reasons, or maybe not, a source for me is meant to be a highly personal prize. If I am giving away my source code I am doing it seriously. I do not take it lightly that my code is being analyzed by potential competitors and such. So I make it my business to ask God for graces all the time. In fact, did you know that I pray 20 minutes each day or more. It is a private time where I give my THANKS to Jesus Christ!

If you read my regular posts compared to my source you can tell that I am a serious coder. It just doesn't carry over into my real life. However I have concerns like everyone else. I worry about my mother being happy all the time. Although I am on government support, I still worry if I have enough to support my family through welfare. I have to confess we live what seems to be a luxurious lifestyle for someone who is on welfare. I never wonder about the costs.

So as a programmer who gives freely my entire works just like someone who works for charity organizations depend on a certain percentage for their living! Anyways, I have to THANK God for sending Jesus Christ and Mary into my life. God has given me two good wonderful parents who have taught me to work and study hard. It is because of their support that I am cared for by my family and friends.

Anyways, I try to go by the principle of The Holy Bible, which is God's words: "Give for free and you shall receive for free."
developertn
9-bit ubernerd
Posts: 833
Joined: March 23rd, 2015, 4:23 pm

God, Jesus Christ, is number one!hehe

Post by developertn »

Jesus Christ!hehe

Emulations can be good especially for programming.

I remember when I was in school, teachers would show example programs.

We, students, would study and learn their way first.

Then when we have grasp all the basic principles we are able to do it our way.

So emulations is not a bad thing.

You may be surprise that I learned much of my programming through looking at examples.

Now I can do basic things however I still need to study more.

For instance, I need to see if I can break the 64K memory model.
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MrFlibble
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Re: Source ports vs. emulation

Post by MrFlibble »

By "emulation" here I meant system/platform emulation, like DOSBox.
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MrFlibble
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Re: Source ports vs. emulation

Post by MrFlibble »

I would like to amend my earlier views stated in this thread, after playing recently some very conservative source ports like DXX-Rebirth, ECWolf or BStone that very successfully address all the issues that bother me in this regard (like aspect correction). I'm convinced that there is no reason to play first-person games at the original low resolution if other options are available.
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MrFlibble
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Re: Source ports vs. emulation

Post by MrFlibble »

I know this discussion is very old, but recently I realised that a lot of 2D sprite-based DOS games actually appear to have graphics that look better with square pixels, even though they would be stretched vertically on a 4:3 CRT screen.

Today I looked at Xargon and realised that this game too appears to have de facto square pixels:
Image
With aspect ratio correction the round objects look oval:
Image
It's a bit hard to judge which version of Malvineous' sprite has more naturally looking proportions though.
Malvineous
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Re: Source ports vs. emulation

Post by Malvineous »

It's an interesting point. I bet if you fire up QBASIC and run the CIRCLE command, you'll only get a true circle with square pixels too.

I seem to remember back in the day that the circles looked pretty round (not perfect but close), so maybe I had just adjusted the vertical size of my CRT so that the pixels came out square? I certainly remember the picture didn't reach the edge of the picture tube horizontally or vertically.

Also what resolution were these games actually running at? I thought DOS text mode was 720x400 and this was the signal sent to the monitor in 320x200 mode as well, with the 320x200 mode being double-scan so effectively 640x400. If it was outputting a 640x400 picture in a 720x400 signal, did it stretch the 640 pixels out to 720 wide, or did the picture appear slightly narrower? If it stretched it horizontally, it could have counteracted some of the distortion. Perhaps your 640x480 image is really supposed to be 720x480? Or were the 720x400 text mode pixels non-square?

I don't have any of my retro PCs set up at the moment to check.
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MrFlibble
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Re: Source ports vs. emulation

Post by MrFlibble »

Malvineous wrote: August 20th, 2021, 6:53 am I bet if you fire up QBASIC and run the CIRCLE command, you'll only get a true circle with square pixels too.
Recently I stumbled upon a video on YouTube that was discussing the issue, and it also mentions the circle tool in DOS-based VGA paint programmes:
https://youtu.be/YvckyWxHAIw?t=274
Malvineous wrote: August 20th, 2021, 6:53 am Perhaps your 640x480 image is really supposed to be 720x480? Or were the 720x400 text mode pixels non-square?
To be very honest, I have only a very vague understanding of the technical side of how a CRT display works. But 640x480 has a 4:3 ratio, and 720x480 apparently does not, so if the CRT screen surface had the 4:3 ratio as well, 640x480 would fit neatly while 720x480 wouldn't?

Anyway, here are a few more interesting articles on the subject:
The Quest for Pixel Perfect DOS Emulation
320x200 : The Resolution of Choice for the IBM PC
Classic DOS Pinball Games, Mode X and What they can Teach Us about Aspect Ratios
Oddball EGA and VGA Resolutions, When the Standard Resolutions Aren't Used
Jazz Jackrabbit on an actual CRT

My idea though is that today we have a choice of how any 320x200 game is displayed in DOSBox. Some definitely look better without aspect ratio correction, regardless of the developers' original intentions. In fact, when I started to look critically at this, I discovered a lot more games that do not benefit at all from aspect=true than I expected.
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