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How early 8-bit arcade machines differed in design from 8-bit home computers

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Re: How early 8-bit arcade machines differed in design from 8-bit home computers

#41

Post by tinus_hn »

jacobush wrote: post #36
tinus_hn wrote: post #31

Earlier quoted context omitted.

The hardware scrolling in the C64 is pretty trivial, it can only shift the screen up to 7 pixels horizontally and vertically and mask the borders a bit. If you want to do scrolling you have to move the memory contents around which costs a lot of cpu time. On a console you typically have a circular buffer and the screen is a movable window on it, so you only have to paint one row every time.

Still, it wasn't like you had to push all the pixels. You only moved 8x8 (or whatever it was) characters. So the C64 was pretty decent, actually. Also, of course you had to shift characters once every 8 pixels. I was envious as hell on my MSX, which had no pixel shifting at all.

It’s very helpful and the implementation is ingenious but not very complicated.

Vertical scrolling changes the timing of the bad lines and horizontal scrolling the timing of the bitmap data fetched and this causes the image to come out at a different position.

There are a lot of creative tricks you can do with this though, especially with vertical scrolling.

Re: How early 8-bit arcade machines differed in design from 8-bit home computers

#42

Post by pjmlp »

jacobush wrote: post #35
callmekit wrote: post #33

Earlier quoted context omitted.

What's wrong with the Spectrum's Green Beret? And R-Type Spectrum conversion was very good.

It didn't magically make the Spectrum have more colors or better sound, like the arcade game had.

Maybe but I did "waste" countless hours with it.

Re: How early 8-bit arcade machines differed in design from 8-bit home computers

#43

Post by scarface74 »

jandrese wrote: post #32
ggambetta wrote: post #29

> And then for the rest of the year spend all my after-school time trying to build rather poor impressions of those arcade games on my home computer, not unlike a cargo-cult worshipper on a post-WWII pacific island trying to build a US military radio station from wooden sticks. Hahaha, this matches my own experience exactly :) Playing the likes of Dragon Ninja / Bad Dudes and then trying to reproduce them on the Spec…

It was a little rare to have an "end" to the games in those days. Generally there wasn't much space for something so extravagant. More often you would overflow a value somewhere and semi-crash the game.

Unless you finally got to the end of Karateka and you walked to the princess....

Re: How early 8-bit arcade machines differed in design from 8-bit home computers

#44

Post by ggambetta »

callmekit wrote: post #33
ggambetta wrote: post #29

> And then for the rest of the year spend all my after-school time trying to build rather poor impressions of those arcade games on my home computer, not unlike a cargo-cult worshipper on a post-WWII pacific island trying to build a US military radio station from wooden sticks. Hahaha, this matches my own experience exactly :) Playing the likes of Dragon Ninja / Bad Dudes and then trying to reproduce them on the Spec…

What's wrong with the Spectrum's Green Beret? And R-Type Spectrum conversion was very good.

Nothing wrong with it, I spent endless hours playing it. But I saw the arcade version only afterwards, and I went "oooooh, colours!"

The "native" Spectrum games were better IMO. Sir Fred comes to mind. Pentagram, Gunfright, Knight's Lore, Abu Simbel Profanation. These worked with the limitations of the hardware (most notably the colour clash), not against it.

I mean, there even was a Spectrum version of Operation Wolf, and it was kind of atrocious (but still unbelievable that they made it work on such modest hardware!)

Re: How early 8-bit arcade machines differed in design from 8-bit home computers

#45

Post by callmekit »

ggambetta wrote: post #44
callmekit wrote: post #33

Earlier quoted context omitted.

What's wrong with the Spectrum's Green Beret? And R-Type Spectrum conversion was very good.

Nothing wrong with it, I spent endless hours playing it. But I saw the arcade version only afterwards, and I went "oooooh, colours!" The "native" Spectrum games were better IMO. Sir Fred comes to mind. Pentagram, Gunfright, Knight's Lore, Abu Simbel Profanation. These worked with the limitations of the hardware (most notably the colour clash), not against it. I mean, there even was a Spectrum version of Operation Wol…

Funny you mentioned Operation Wolf, this is a game I really like and still play in the emulator from time to time.

Re: How early 8-bit arcade machines differed in design from 8-bit home computers

#46

Post by axilmar »

cmrdporcupine wrote: post #27
axilmar wrote: post #3

I will forever wonder why 8-bit computers of the 80s didn't have more powerful video hardware. It's not that the technology wasn't available, since most arcade machines at the time had a lot more powerful graphics hardware than 8-bit home machines. (I will also forever wonder why Sega's 16-bit console didn't have hardware sprite scaling and rotation, since that was the main attraction of Sega games at the time...) I…

Well it almost certainly was cost. Memory was expensive. Address space was limited to 64k. And most importantly, user's displays were color TVs with terrible resolution. Arcade games shipped w/ high quality CRTs. Back in the 80s very few of us had that luxury. My display on my VIC-20 was a 9" B&W TV that my parents had lying around. Also if you look at something like the Atari 800, it had at least a subset of what yo…

Our TVs where fine for the resolution of, for example, ZX Spectrum. C64 and Atari and Amstrad CPC graphics looked extremely blockly on our televisions/dedicated monitors (well the Amstrad had such a beast).

I had connected all the above (spectrum, c64, atari) first to a 40 inch b/w tv, then to a 32 inch color tv. Guess what? the spectrum image was visibly blockly, and the c64/atari image was incredibly blocky.

Furthermore, you didn't need another 64k for video ram; there where a lot of palette tricks that could be done. Even if 64k ram were added, the price difference would be small in the end.

So I don't buy it it was the cost; most probably it was the shortsightedness of the designers.

Re: How early 8-bit arcade machines differed in design from 8-bit home computers

#47

Post by axilmar »

tom_ wrote: post #11
axilmar wrote: post #3

I will forever wonder why 8-bit computers of the 80s didn't have more powerful video hardware. It's not that the technology wasn't available, since most arcade machines at the time had a lot more powerful graphics hardware than 8-bit home machines. (I will also forever wonder why Sega's 16-bit console didn't have hardware sprite scaling and rotation, since that was the main attraction of Sega games at the time...) I…

It would have been quite a lot more expensive, I assume? Roughly speaking, with 2MHz RAM, and assuming a setup where the CPU and the display system alternate (so 1,000,000 bytes/second bandwidth for each), you have a budget of 40 bytes for the visible part of the line, and large buffers are expensive, so it's just a question of how you spend it. Take the C64 as an example: you've got 320 px mono (40 bytes/line), 160…

64 bytes per scan line X 200 scan lines = 12,800 bytes.

1,000,000 / 12,800 = 78.125

i.e. frame rate = 78 frames per second could be updated with that speed.

I am sure 78 frames per second are not really desirable, so the resolution could actually be doubled per scan line:

128 bytes per scan line X 200 scan lines = 25,600

1,000,000 / 25,600 = 39 frames per second.

Re: How early 8-bit arcade machines differed in design from 8-bit home computers

#48

Post by axilmar »

mikepavone wrote: post #40
axilmar wrote: post #3

I will forever wonder why 8-bit computers of the 80s didn't have more powerful video hardware. It's not that the technology wasn't available, since most arcade machines at the time had a lot more powerful graphics hardware than 8-bit home machines. (I will also forever wonder why Sega's 16-bit console didn't have hardware sprite scaling and rotation, since that was the main attraction of Sega games at the time...) I…

> (I will also forever wonder why Sega's 16-bit console didn't have hardware sprite scaling and rotation, since that was the main attraction of Sega games at the time...) An interview with one of the hardware designers on the Mega Drive/Genesis VDP suggests they wanted this, but that didn't have enough die space. It's also not clear how comparable to their arcade hardware this would have actually been even if it was…

I don't buy that at all as well. They could have made the console a bit bigger, and a bit more flexible inside.

I wasn't asking for the full powerdrift arcade experience, but something that can emulate it to a certain degree.

Re: How early 8-bit arcade machines differed in design from 8-bit home computers

#49

Post by ggambetta »

callmekit wrote: post #45
ggambetta wrote: post #44

Earlier quoted context omitted.

Nothing wrong with it, I spent endless hours playing it. But I saw the arcade version only afterwards, and I went "oooooh, colours!" The "native" Spectrum games were better IMO. Sir Fred comes to mind. Pentagram, Gunfright, Knight's Lore, Abu Simbel Profanation. These worked with the limitations of the hardware (most notably the colour clash), not against it. I mean, there even was a Spectrum version of Operation Wol…

Funny you mentioned Operation Wolf, this is a game I really like and still play in the emulator from time to time.

Definitely not the same without the light gun :(

Re: How early 8-bit arcade machines differed in design from 8-bit home computers

#50

Post by tinus_hn »

cmrdporcupine wrote: post #38
tinus_hn wrote: post #31

Earlier quoted context omitted.

The hardware scrolling in the C64 is pretty trivial, it can only shift the screen up to 7 pixels horizontally and vertically and mask the borders a bit. If you want to do scrolling you have to move the memory contents around which costs a lot of cpu time. On a console you typically have a circular buffer and the screen is a movable window on it, so you only have to paint one row every time.

Atari 8-bit could fine scroll horizontal and vertical. In 1979. https://www.atarimagazines.com/compute/issue67/338_1_Atari_F...

Which is the same circular buffer. Great if you can spare the memory, it uses twice as much if you want to scroll in one direction or four times if you want both directions.

On the C64 that’s 8k which is a lot if 16k is all you get (the video chip only has enough address lines to address 16k).

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