 Previous Messages |
Posted By
Stinaris
on 2021-02-05
06:11:17
 |  Re: Source Code of Demon Attack (Atari 2600)
The 2600 is not a good place to start.
Effectively you have to program it at the hardware level. Not the hardware level of the console but of the TV.
It has no frame buffer so you cannot just set a pixel, as these don't exist. The image is controlled in clock cycles and you have to tell it what to draw so all the time the image is being updated on the screen you cannot run any application code.
To make this even worse it uses a MOS 6507 (it's not an upgrade). This has no interrupts and a reduced address bus (13 bits) to save money. So you can't even set up an interrupt when the screen update is done. You have to calculate the clock cycles manually. Get it wrong, your display is unviewable.
Reverse engineering the code would be a bit of a PITA.
2600 programmers are proper hardcore and David Crane is a god!
Why not convert something like this?
https://vintageisthenewold.com/fire-a-new-gamewatch-game-for-the-commodore-64/
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Posted By
KiCHY
on 2021-02-04
10:40:30
| Re: Source Code of Demon Attack (Atari 2600)
I'm sure somebody here will help you out with graphics. Don't hesitate to ask. I too often read "sry for the graphics, I'm not a talent" - and he/she never asked for help in graphics.
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Posted By
register
on 2021-02-04
03:28:19
| Re: Source Code of Demon Attack (Atari 2600)
I have resumed to program and have decided to start with this simple game. Here a very early early preview of the sprite routine:
My graphic fu sucks so I would be glad if somebody could help with the graphics
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Posted By
Csabo
on 2013-12-19
19:58:34
| Re: Source Code of Demon Attack (Atari 2600)
Converting from Java to machine language is a non-starter for me. I mean all that the Java source code would help is perhaps scoring and some other game mechanics, but otherwise you're writing a new game from scratch.
I'm personally involved in several projects, so I don't have much free time, but even if I did, I'd have to give this one a pass. Of course I can't speak for anyone else, but IMHO don't hold your breath on this one... Perhaps try to look for something that's easier to convert (e.g. C64 games with no sprites  )
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Posted By
George
on 2013-12-19
17:06:02
 | Re: Source Code of Demon Attack (Atari 2600)
Hi Angelsoft,
lets hope, that they started coding silently... I have a nostalgic connection to this game, since it started my computer carreer.
I analysed the Java Code a little, and the key routines should be the Sprite and the Line routines, which sure exist in other games, since the graphics are not that complicated and noumerous. But let the experienced guys judge this.
The Vic 20 Game plays **FANTASTIC**. I play it often on a emulator. Very near to the Atari game. I also think that the VIC 20 version is the better choice for a possible conversion.
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Posted By
angelsoft
on 2013-12-19
16:34:56
 | Re: Source Code of Demon Attack (Atari 2600)
Hm, noone has replied yet. Have the developers already started coding silently..? 
I had a look at the game. It's pretty good designed and nice to play (although it's just a shooter). It's quite amazing what the imagic folks squeezed out of the Atari 2600 in 4k of ROM. But As far as I know, the architecture of Atari 2600 ("Stella") and C16/Plus/4 is very different. Stella has sprites and needs programming very near to the video chip while with C16 one can only use the text screen with a self-defined character set or hires programming, but the latter is probably too slow and would use too much memory on a C16. I had a look if there's a C64 port of demon attack but that is using sprites, too (see http://www.gb64.com/game.php?id=2104&d=18&h=0) and it's quite ugly, even though the programmers had much more memory.
I found that there is also a VC-20 port of demon attack done by imagic, too (see http://www.youtube.com/watch?v=xCPHm43WfDE). This one should be architectural quite similar to what it would be on a C16, because a VC-20 has no sprites. And in the youtube video it looks very near to the Stella original. Maybe there's some folks who are experienced in VC-20 programming and might want to port it.
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Posted By
George
on 2013-12-17
10:01:16
| Source Code of Demon Attack (Atari 2600)
I found the scource code of Demon Attack in Java (without sound) and Assembler for the 2600 in the net (4k). Anybody experienced in converting Java Code or 2600 games to the plus 4? I would take years to convert it myself.
Demon Attack is perhaps the most playable Shooter for the Atari 2600.
Java Game: Demon Attack
Converted Screen:
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