Commodore 64 vs Atari 800 Xl

[potatohead]

I don't actually think they are about the same in capability. That is precisely what makes the older machines interesting. On a lot of mainstream projects, the trade-offs appear to be straight-forward. As soon as one dives into a strength of one of the machines, the other becomes quite challenging.

 

The C64 can do colorful bitmaps, and it can do so very easily, getting it's 16 colors on the screen, and draw those pixels at 320 pixel color resolution. That's great for pixel art. It can also do sprite objects that are larger and easier to manipulate. Color cells make these things possible, and compensating with PM tricks is tough!

 

The Atari capabilities are different, more involved, and at a generally lower resolution. That Space Harrier game and the Wolf clone are two excellent examples of that. I would toss YOOMP! in that as well, due to it matching well with the Atari hardware, making ports difficult on machines that don't have the CPU speed, and or graphics hardware modes to match. Compensating with clever code, and or RAM becomes tough in like kind!

 

Pushing that edge is where the fun is! Crownland is another A8 example --and a fine one too, where that kind of game is outside the norm for the A8 machines, but ends up being possible with a lot of work.

 

At the end of the day, I've got retro machines in the house here and enjoy them. Nobody needs to validate anything for anyone else, and that's the truth of it. You love the boxes you love, and over time, maybe check out some of the other ones and expand your retro experience. This works just like music does. Sample a little, get interested, then appreciate it. Once an era is gone, it's gone, meaning no more. If that gets dull, that's what the other machines are for.

[ceti331]

Has anyone got any stills of A8 representations of converted photographs/modern bitmaps, at 160x192 resolution

maybe generated by seperately palettizing each scanline ..something like that.

[PeteD]

Has anyone got any stills of A8 representations of converted photographs/modern bitmaps, at 160x192 resolution

maybe generated by seperately palettizing each scanline ..something like that.

 

Have a search for quantizator. Myself and a few other people have written converters that do 4 different colours per scanline and I'm just about to finish one that adds support for PMGs and mid-scanline register changing to get even more colours. Most of the examples are probably in the quantizator thread (sorry can't remember the coder off hand).

 

 

Pete

[DimensionX]

Crownland was quite impressive.

 

Speedrun of the first level

[PeteD]

 

 

At the end of the day, I've got retro machines in the house here and enjoy them. Nobody needs to validate anything for anyone else, and that's the truth of it. You love the boxes you love, and over time, maybe check out some of the other ones and expand your retro experience. This works just like music does. Sample a little, get interested, then appreciate it. Once an era is gone, it's gone, meaning no more. If that gets dull, that's what the other machines are for.

 

Absolutely I've started doing some BBC coding as it was my first machine and I didn't really produce much on it (the usual educational software I sold to the school where my mom was a teacher), just learned the basics of 6502 which I then took to the C64 (via my brush with the speccy). I've gotten back into the beeb internals after doing some work on running native beeb code on the Atari (and now C64) and it's nice that there's not a lot to learn, it's all about how the HELL do I fit this 16 colour game into 32k when a 16 colour screen takes 20k and what can I do with this nice 2mhz cpu with a 4mhz bus (answer is, reduce the screen size for a start, something easily done on the beeb)

 

Same goes for the z80 based machines. I learned z80 a looooooong time ago and after looking at it again recently it's slipped nearly totally from my head but I do plan on doing some speccy/cpc stuff at some point, just because they're there.

 

For coders who enjoy this stuff there are endless possibilities and every coder has 100x more stuff on their todo list than there's time to work on.

 

Pete

[ceti331]

Have a search for quantizator. Myself and a few other people have written converters that do 4 different colours per scanline and I'm just about to finish one that adds support for PMGs and mid-scanline register changing to get even more colours. Most of the examples are probably in the quantizator thread (sorry can't remember the coder off hand).

Pete

 

thats quite impressive, interesting stuff.

r.e Quantizator, to really throw the cat amongst the pigeons we should get some side by side pictures of C64 &per-line A8 paletizer

 

 

Regarding mid-line register changing - how intensive was this.. is it possible to horizontally re-use sprites?

Edited April 29, 2010 by ceti331

[DimensionX]

Paul woakes must have been a programmer genius?

 

Damocles was huge, real huge, and everything was in real 3D. A whole universe to travel in with planets to visit. You could enter all buildings on the planets in real 3D. Just take the moon Midas among many different planets for exemple. Midas contained 16.000.000 (16 million) invidual numbered pyramids, which you could enter. How the heck do you fit such game in 350 Kb?

http://mercenarysite.free.fr/merce.htm

[PeteD]

Have a search for quantizator. Myself and a few other people have written converters that do 4 different colours per scanline and I'm just about to finish one that adds support for PMGs and mid-scanline register changing to get even more colours. Most of the examples are probably in the quantizator thread (sorry can't remember the coder off hand).

Pete

 

thats quite impressive, interesting stuff.

r.e Quantizator, to really throw the cat amongst the pigeons we should get some side by side pictures of C64 &per-line A8 paletizer

 

 

Regarding mid-line register changing - how intensive was this.. is it possible to horizontally re-use sprites?

 

There should be some in that thread? I posted some somewhere, can't remember if it was in there or one of the Vs threads

 

Mid line changes you can reuse the sprites but there are so few changes available across the screen its better to just pick a colour register to change each time. The sprites, easiest way to use them is a pseudo colour ram, make them quad expanded so they fill a full 320 wide screen. They'll be mono of course and only give a 8:1 pixel AR but that's a close (ish) equivalent to C64 colour RAM (at least in size). Then its a matter of deciding where it's best (if at all) to change the sprite colours or to just use them as an extra background colour for each 1/4 X of the screen.

 

*edit*

You get more problems trying to use the 4/5 colour character mode thing. Yes you get an extra colour but with the added complexity of that not being allowed in the same character as its alternative (but that's really a converter issue) plus running the screen in character mode instead of bitmap so you can use the extra colour means a "badline" every 8 lines taking up an extra 40 cycles and reducing the number of colour changes you can have on that line. Once again, really a converter issue I suppose because it's a known variable.

 

 

Pete

Edited April 29, 2010 by PeteD

[PeteD]

Paul woakes must have been a programmer genius?

 

Damocles was huge, real huge, and everything was in real 3D. A whole universe to travel in with planets to visit. You could enter all buildings on the planets in real 3D. Just take the moon Midas among many different planets for exemple. Midas contained 16.000.000 (16 million) invidual numbered pyramids, which you could enter. How the heck do you fit such game in 350 Kb?

http://mercenarysite.free.fr/merce.htm

 

Same type of way Elite fit in so many named planets in so many solar systems + a complex game all in 32k. Use a seeded number generator such as Fibonacci to create your "world".

 

 

Pete

[DimensionX]

Paul woakes must have been a programmer genius?

 

Damocles was huge, real huge, and everything was in real 3D. A whole universe to travel in with planets to visit. You could enter all buildings on the planets in real 3D. Just take the moon Midas among many different planets for exemple. Midas contained 16.000.000 (16 million) invidual numbered pyramids, which you could enter. How the heck do you fit such game in 350 Kb?

http://mercenarysite.free.fr/merce.htm

 

Same type of way Elite fit in so many named planets in so many solar systems + a complex game all in 32k. Use a seeded number generator such as Fibonacci to create your "world".

 

 

Pete

 

Thanks!

 

It's quite fantastic how much you can fit it in a relative tiny amount of code using some tricks.

[PeteD]

Paul woakes must have been a programmer genius?

 

Damocles was huge, real huge, and everything was in real 3D. A whole universe to travel in with planets to visit. You could enter all buildings on the planets in real 3D. Just take the moon Midas among many different planets for exemple. Midas contained 16.000.000 (16 million) invidual numbered pyramids, which you could enter. How the heck do you fit such game in 350 Kb?

http://mercenarysite.free.fr/merce.htm

 

Same type of way Elite fit in so many named planets in so many solar systems + a complex game all in 32k. Use a seeded number generator such as Fibonacci to create your "world".

 

 

Pete

 

Thanks!

 

It's quite fantastic how much you can fit it in a relative tiny amount of code using some tricks.

 

I think the pyramids bit is done from a formula based on your world position. Like take your X/Y location (or x/z) and juggle those numbers so it's not as simple as going up in X increases the pyramid number by 1. There was a calculation you could do to get the world coordinates of the pyramid you needed from a clue on another planet.

 

 

Pete

[TMR]

I've gotten back into the beeb internals after doing some work on running native beeb code on the Atari (and now C64) and it's nice that there's not a lot to learn, it's all about how the HELL do I fit this 16 colour game into 32k when a 16 colour screen takes 20k and what can I do with this nice 2mhz cpu with a 4mhz bus (answer is, reduce the screen size for a start, something easily done on the beeb)

 

i've seen quite a few interesting things on the BBC lately, a new

(which plays SID music) at Console Combat. The same coder has been patching up games for release through Retro Software (the BBC equivalent of Atari Age, essentially) and he showed me a way to get horizontal scrolling in pixel steps for 160x256 at Retro Reunited last year that's apparently never been used because commercially due to sync issues with some monitors... but despite trying it on the ones that were supposed to fail during the event, he found that it worked every time!

 

Same goes for the z80 based machines. I learned z80 a looooooong time ago and after looking at it again recently it's slipped nearly totally from my head but I do plan on doing some speccy/cpc stuff at some point, just because they're there.

 

i wrote a truly appalling software sprite routine for the Spectrum last week and that was... an interesting experience - it's my first time with Z80 and since i do a lot of self mod on the 6502 machines it just seems alien working with all those registers. i must've been doing something seriously wrong too, because i ran out of registers before i could get things moving horizontally!

 

For coders who enjoy this stuff there are endless possibilities and every coder has 100x more stuff on their todo list than there's time to work on.

 

Yeah, my work files are full of experiments and tests; for the Atari 8-bit alone i've got three or four different player-based sprite engines, a 128x80 pixel scroll that uses a single LMS and EORs sprites in over the top, that underlay system used in

, a few tests at 320x200 res single pixel scrolling (and that goes totally to crap if artefacting is enabled in the emulator), part of an 80x192 pixel vertical scroller with greyscale backgrounds and horizontally expanded sprites that have rainbows through them, a picture shuffling game based on the old MSN thing Blender that runs in APAC and another variant of the same that works at 160x80 with 64 colours, prototype code for an A8 version of

... most of this stuff will probably never see the light of day (and some of it probably isn't workable for a decent game anyway) but it's like an audition process, the routines are tested and, if they pass muster, an idea for something fun will present itself. Edited April 29, 2010 by TMR

[Bryan]

I've written Z80 code, but boy do I prefer the 6502.

 

 

 

 

 

 

 

...and rainbows

[TMR]

I've written Z80 code, but boy do I prefer the 6502.

 

Well, what i've seen so far is a feckin' nightmare... plus at the moment there's that vague air of my code being utterly shite because i'm doing everything wrong! The Spectrum doesn't make things easier, about the only reliable way to get vertical blank sync appears to be right at the top of the screen...

 

...and rainbows

 

But ain't they a pain in the arse to get working if you're trying to run a decent sprite engine, character-based scrolling and so on...!

[PeteD]

I've written Z80 code, but boy do I prefer the 6502.

 

Well, what i've seen so far is a feckin' nightmare... plus at the moment there's that vague air of my code being utterly shite because i'm doing everything wrong! The Spectrum doesn't make things easier, about the only reliable way to get vertical blank sync appears to be right at the top of the screen...

 

Interrupt at top of screen, Yup Crap isn't it. My first boss was amazingly pleased with himself after getting a glitch free colour bar through some text about 1/4 of the way down the screen on our fist game

 

afaik there's an NMI line on the chip but it's disconnected so it actually does nothing.

 

The display is somewhat mental as well, contiguous bytes, ooo now down 8 lines, etc etc then down 1/3 of the screen.

 

Z80 is one of those processors that looks like it'll make your life easy then you start coding and run out of those extra registers due to addressing

 

 

Pete

[sack-c0s]

I've written Z80 code, but boy do I prefer the 6502.

 

Well, what i've seen so far is a feckin' nightmare... plus at the moment there's that vague air of my code being utterly shite because i'm doing everything wrong! The Spectrum doesn't make things easier, about the only reliable way to get vertical blank sync appears to be right at the top of the screen...

 

 

I used to quite like the gameboy colour - Z80 with the really odd bits stripped out and nice sprite/background hardware. It was like coding 6502 only with a bit of elbow room on the register front

 

it was nice and easy to do rainbows too.

 

For the speccy I had to just resort to a per-line lookup table for the start addresses, but at least it'd make a lazy CPC port possible

Edited April 30, 2010 by sack-c0s

[Bryan]

...and rainbows

 

But ain't they a pain in the arse to get working if you're trying to run a decent sprite engine, character-based scrolling and so on...!

 

I'm confused. Why do you need sprite engines or scrolling if you have rainbows?

 

 

BTW, there's a pretty cool looking new Atari game out: http://hdm.atari.pl/index.html

[potatohead]

Nice. I've gotta hurry up and finish saving for my SIO to something device...

 

I really like the GITA intro screen. Great use of the chunky pixels. Reading the development story now. Love it when they do that.

 

 

...and rainbows

 

But ain't they a pain in the arse to get working if you're trying to run a decent sprite engine, character-based scrolling and so on...!

 

I'm confused. Why do you need sprite engines or scrolling if you have rainbows?

 

 

BTW, there's a pretty cool looking new Atari game out: http://hdm.atari.pl/index.html

[+wood_jl]

Hasn't the ST got a bit of a crappy RF out as well? I always thought it looked a bit dull and washed out.

Pete

 

Most RF is crappy by nature, not to blame the ST. My STs have, actually, pretty nice RF out. Still crap since they're RF, but they rate highly RF-wise.

[DimensionX]

...and rainbows

 

But ain't they a pain in the arse to get working if you're trying to run a decent sprite engine, character-based scrolling and so on...!

 

I'm confused. Why do you need sprite engines or scrolling if you have rainbows?

 

 

BTW, there's a pretty cool looking new Atari game out: http://hdm.atari.pl/index.html

 

Aaah, Florida "swamp jokes?" For the natives? The people with 5cm thick glasses and 30 cm long beards?

 

Well, let's get down to business....

 

With that kind of "humour", you're either

 

1.Florida swamp native

2.65+

3.Or, wearing very thick glasses

 

Do you like jokes about compression algorithms too? I think you should keep your "funny jokes" to yourself because the only funny thing about them is the feeling of someone being incredible naive and gullible without even understanding it.

 

And yes, i like A8's special graphics that no other computer can display. To see something like C64, but way better, watch Atari ST in action. To watch something like A8, the only thing is to watch another A8 in action. Either you like it, or not, but that's A8.

Edited May 1, 2010 by DimensionX

[PeteD]

..and so it begins again. I hate to say I told you so, but..

[TMR]

And yes, i like A8's special graphics that no other computer can display.

 

Apart from the Amstrad CPC Plus. Or the CoCo3. Or the MSX2, MSX2+ or MSX Turbo R. Or even supercharged C64s like the C64DX and C64DTV. Or even the Commodore 264 series. For graphics that "no other computer can display" there are a lot of machines that can either display what you're talking about or do it better out there...

[DimensionX]

And yes, i like A8's special graphics that no other computer can display.

 

Apart from the Amstrad CPC Plus. Or the CoCo3. Or the MSX2, MSX2+ or MSX Turbo R. Or even supercharged C64s like the C64DX and C64DTV. Or even the Commodore 264 series. For graphics that "no other computer can display" there are a lot of machines that can either display what you're talking about or do it better out there...

 

In that case i don't think that you understand what i mean by Atari graphics. Does Amstrad CPC has the Antic and GTIA chip? If not, it can't display what i call Atari graphics. No game on my Amstrad or MSX emulator even looks like an Atari game, no matters how many colours they use. Atari ST can't display A8 graphics either.

 

A8 is exactly like Spectrum, unique in it's way to display graphics.

 

Not even the XL series could match the outstanding colours of the first Atari 800 model.

Edited May 1, 2010 by DimensionX

[Audiophile]

You may call me stupid, but I am convinced that the atari is still not fully discovered.

It is possible that people have to push the atari to its limits for being the same as the c64 is some cases.

Both machines I think have to be pushed to their limits to be the same in capabilities.

 

Like I said before many people thought that the ST was not able to do some things the Amiga could, thanks to some clever demo coders it suddenly became possible.

The same just has to go for the older machines, why not push the older machines to their limits and in some areas I believe okay its already done.

For example guys : When we see a finished port of Turrican on the atari xl (the beginning can be seen on youtube) I think the c64 guys (who think their machine is the best) will admit that the atari xl can do more than they think.

I also read on the internet that there are more games in development, is seems that those games promise a lot.

 

I stay with my opinion that both c64 and atari xl are about the same.

[DimensionX]

You may call me stupid, but I am convinced that the atari is still not fully discovered.

It is possible that people have to push the atari to its limits for being the same as the c64 is some cases.

Both machines I think have to be pushed to their limits to be the same in capabilities.

 

Like I said before many people thought that the ST was not able to do some things the Amiga could, thanks to some clever demo coders it suddenly became possible.

The same just has to go for the older machines, why not push the older machines to their limits and in some areas I believe okay its already done.

For example guys : When we see a finished port of Turrican on the atari xl (the beginning can be seen on youtube) I think the c64 guys (who think their machine is the best) will admit that the atari xl can do more than they think.

I also read on the internet that there are more games in development, is seems that those games promise a lot.

 

I stay with my opinion that both c64 and atari xl are about the same.

 

If we take a look at this game.

 

You can do quite amazing things with A8 too.

 

I would like to see that, on a C64.

Edited May 1, 2010 by DimensionX