6 ms·

AGI-64 Brings Sierra Adventures to the Commodore 64

129 points by erickhill 1mo ago

a1o 1mo ago
Wait, how? What is the background technology? I need more explanation. Is this a tool to recompile these games?
- wzdd 1mo ago
  AGI is here and its first task is obviously completing the C64’s game library. Not really. AGI is a game interpreter, like LucasArts’ SCUMM or Infocom’s z machine. Games are shipped as portable code and a machine specific AGI interpreter runs them. Looks like they’re preprocessing the graphics first, though. https://en.wikipedia.org/wiki/Adventure_Game_Interpreter https://en.wikipedia.org/wiki/Adventure_Game_Interpreter
  - skissane 1mo ago
    Sierra released most of their AGI games on the Apple IIc/IIe. Given C64 is a roughly equivalently specced machine, there is no reason in principle why they couldn't have ported AGI to C64 as well – it just, for whatever reason, never happened. (One AGI game, "Donald Duck's Playground", was originally developed as a native C64 game, then AGI was used to port it to other platforms.) Also, given different AGI platforms had different graphics capabilities, I expect even the original Sierra AGI games had somewhat different graphics assets on different platforms – so whatever preprocessing of graphics they are doing to make them C64-friendly, Sierra quite possibly would have done something like that anyway had they made a C64 port back in the day.
    - TMWNN 1mo ago
      > Given C64 is a roughly equivalently specced machine, there is no reason in principle why they couldn't have ported AGI to C64 as well – it just, for whatever reason, never happened. Agreed about the issues not being (completely) technical. <https://np.reddit.com/r/c64/comments/1r8hgwk/kings_quest_i/o670li7/?context=3 https://np.reddit.com/r/c64/comments/1r8hgwk/kings_quest_i/o...>
    - Firehawke 1mo ago
      If I recall correctly, the art is done with a form of early vector drawing so that they can use one set of assets on all platforms. They're designed to 16 colors but get downsampled for 4-color CGA mode or monochrome mode.
      - glhaynes 1mo ago
        I've always imagined it to be first and foremost about storage savings. Although, come to think of it, an RLE-encoded bitmap might be comparable since we're talking about images with large areas of so few colors. Might be interesting to do an empirical test. But, yes, it's all a bunch of vector draw/fill commands. The first few AGI games showed that process happening; and, as a little kid having one of their first encounters with a computer, I found it fascinating to watch. Later games drew it in an offscreen buffer and showed it all at once, which looked more "professional" but took away some magic. Here's a video showing the drawing process: https://www.youtube.com/watch?v=v5DSFvWrNWA https://www.youtube.com/watch?v=v5DSFvWrNWA. Magic! EDIT: I had an agent make a guess and it came up with reasonable looking numbers that said an RLE bitmap would be a small handful of times larger. But it also interestingly pointed out that the vector commands encoded priority (i.e., what you can walk behind/through) whereas that'd have to be a second data set for a bitmap approach.
        WorldMaker 1mo ago
        The vector art also included some complex dithering patterns that balloon RLE-encoded bitmaps. Dithered drawing is actually one of the worst cases for simple, pure RLE. For dithering compatible bitmap encoding you would want other more complex compression schemes than simple RLE. Some of the palette-based compression techniques of "modern" GIF were reused from such early predecessors, even though there's a belief today that RLE was most of what games at the time used. (It's useful to point out that early AOL was also heavily dithered, especially in monochrome versions. AOL also spanned the gap between dithered, heavily palette-based graphics to "early modern graphics".)
      - kolanos 1mo ago
        Yes, this is correct. I have a distinct memory of playing Space Quest (forget if I or II) on a CGA monitor and then seeing it on my friend's EGA monitor and being blown away.
  - noufalibrahim 1mo ago
    I think the first instance of games being separated from the "engine" so that you could make the game and it would run on all platforms that the engine ran out without porting was Infocom's Z-machine. http://maher.filfre.net/if-book/if-4.htm http://maher.filfre.net/if-book/if-4.htm There was an interesting article which I read a long time. It's linked to from the post above called "How to Fit a Large Program into a Small Machine" published in 1980. AGI, SCI, Scumm etc. were all larger and more capable versions of this.
    - anthk 1mo ago
      Also, a micro Inform6 compiler+library: https://github.com/johanberntsson/PunyInform https://github.com/johanberntsson/PunyInform Tristam Island as an example: https://github.com/hlabrand/tristam-island https://github.com/hlabrand/tristam-island
      - gapan 1mo ago
        Also, ozmoo, a z-machine interpreter for the C64 (+other 8-bit machines) with several qualify of life improvements. https://github.com/johanberntsson/ozmoo https://github.com/johanberntsson/ozmoo https://ozmoo.online/ https://ozmoo.online/
    - WorldMaker 1mo ago
      Z-Machine is also useful to point out because it's one of the clearest lines to draw from it to the modern JVM and .NET CLR. Whereas AGI/SCI/SCUMM all have very game specific virtual machines, Infocom's was Lisp influenced and even built it with business/enterprise apps in mind, though Infocom's one attempt at doing exactly that with their database app Cornerstone was a market flop. (It's heavily enhanced fork of the Z-Machine was also only released for a fraction of the machines the game Z-Machine supported.) I still think it's an interesting question if Infocom had not tried to keep the Z-Machine proprietary "secret sauce" if it would have been a larger platform of general computing for much longer and broader than Infocom's own lifespan and primarily games focus. If Infocom had taken a Sun-like stance on the Z-Machine being a JVM ahead of its time and building a broader compatibility ecosystem "write once, run everywhere" might have been an earlier part of computing.
songhonglei1985 1mo ago
[dead]
trollbridge 1mo ago
The fusion of "64-bit architectures" and "64K total RAM machine" brings a bit of a smile to my face with projects with names like this.
JoshTriplett 1mo ago
The only good AGI. Impressive fitting into the machine. I wonder if SCI would be possible?
- bzzzt 1mo ago
  Only with some serious downgrading of the assets. I remember playing SCI games on an 8MHz XT class PC and everything ran dog slow. Some SCI games had optional animations that didn't play on a slow machine.
- stuaxo 1mo ago
  Now this is an AGI I can get behind.
- aidenn0 1mo ago
  AGI was an impressive game engine. It's just a shame it was wasted on so many bad games.
  - JoshTriplett 1mo ago
    Some of them weren't wildly worse than the era. I think many old games substituted punishing difficulty for depth, so that they'd have more staying power. That was true of some of the early NES games as well.
    - aidenn0 29d ago
      I agree that they weren't terrible for the era, but they weren't great either. I'll pick on SQ1, since that's the highlight of TFA. Obtaining the Jetpack is not just punishingly difficult, even once you get to the point where you know you need a jetpack there are zero hints where you might obtain one; the only solution is to replay the game and try random things differently than the first time you played through.
      - JoshTriplett 28d ago
        Yeah, agreed. Many games did the same, but that didn't make it good. On the "cruelty scale", that'd be a "Cruel", since it has a "walking dead" state of "you did it wrong a while back and have to start over": https://eblong.com/zarf/essays/cruelty.html https://eblong.com/zarf/essays/cruelty.html (and https://eblong.com/zarf/essays/cruelty-revisited.html https://eblong.com/zarf/essays/cruelty-revisited.html ) Early King's Quest games were in that same category of "Cruel", where an incorrect choice is not immediately obvious as a mistake. I think King's Quest V was closer to "Nasty" (because it can catch you off guard with things you fail, but it'll be obvious that you did something wrong). But there are a couple of exceptions that keep it in "Cruel", though: you can eat the wrong item when you're starving, and in some cases if you miss picking up an item you can't go back for it, so if you didn't see it at all then you have to go back to an earlier save. That one definitely required keeping a full array of save files. (Very satisfying to complete, though.) Even King's Quest VI, which is much more forgiving, has some cases of "you need the right item before proceeding into this section you won't be able to leave (for a while)". But it goes out of its way to advertise those "points of no return", so I'd rate it firmly at "Nasty" rather than "Cruel", with the asterisk that there are ~3 notable points where you might have to go back by more than just your most recent action, but it'll be obvious you want save points at those points to go back to if you find you can't progress inside. (Before the catacombs, before the land of the dead, before entering the castle.) The entry to the catacombs even offers you the chance to go prepare further, if and only if you don't have everything you need.
TMWNN 1mo ago
Excellent! Five months ago I wrote about why Sierra never released AGI games for C64; it was not technical so much as market focus. <https://np.reddit.com/r/c64/comments/1r8hgwk/kings_quest_i/o670li7/?context=3 https://np.reddit.com/r/c64/comments/1r8hgwk/kings_quest_i/o...>
madhu_ghalame 1mo ago
[dead]
hn974izqdv 1mo ago
Simple advice, hard to follow
vkaku 1mo ago
We finally achieved AGI outside these AI companies on portable home computers
mromanuk 1mo ago
I know what is AGI, I read the queues Adventures, Sierra, should be obvious where this lead. But my mind went to "oh, thanks to LLM coding agents, they massively ported every Sierra Adventure to C64".
- pimlottc 1mo ago
  *cues
1970-01-01 1mo ago
>Made for a 1 MHz machine That's impressive work. It's fun to think how today's CPU rounding errors can run hit adventure games. Your smartwatch uses more cycles to render the time.
just60sec 29d ago
[dead]

129 points by erickhill 1mo ago

a1o 1mo ago

Wait, how? What is the background technology? I need more explanation. Is this a tool to recompile these games?

wzdd 1mo ago
AGI is here and its first task is obviously completing the C64’s game library. Not really. AGI is a game interpreter, like LucasArts’ SCUMM or Infocom’s z machine. Games are shipped as portable code and a machine specific AGI interpreter runs them. Looks like they’re preprocessing the graphics first, though. https://en.wikipedia.org/wiki/Adventure_Game_Interpreter https://en.wikipedia.org/wiki/Adventure_Game_Interpreter
- skissane 1mo ago
  Sierra released most of their AGI games on the Apple IIc/IIe. Given C64 is a roughly equivalently specced machine, there is no reason in principle why they couldn't have ported AGI to C64 as well – it just, for whatever reason, never happened. (One AGI game, "Donald Duck's Playground", was originally developed as a native C64 game, then AGI was used to port it to other platforms.) Also, given different AGI platforms had different graphics capabilities, I expect even the original Sierra AGI games had somewhat different graphics assets on different platforms – so whatever preprocessing of graphics they are doing to make them C64-friendly, Sierra quite possibly would have done something like that anyway had they made a C64 port back in the day.
  - TMWNN 1mo ago
    > Given C64 is a roughly equivalently specced machine, there is no reason in principle why they couldn't have ported AGI to C64 as well – it just, for whatever reason, never happened. Agreed about the issues not being (completely) technical. <https://np.reddit.com/r/c64/comments/1r8hgwk/kings_quest_i/o670li7/?context=3 https://np.reddit.com/r/c64/comments/1r8hgwk/kings_quest_i/o...>
  - Firehawke 1mo ago
    If I recall correctly, the art is done with a form of early vector drawing so that they can use one set of assets on all platforms. They're designed to 16 colors but get downsampled for 4-color CGA mode or monochrome mode.
    - glhaynes 1mo ago
      I've always imagined it to be first and foremost about storage savings. Although, come to think of it, an RLE-encoded bitmap might be comparable since we're talking about images with large areas of so few colors. Might be interesting to do an empirical test. But, yes, it's all a bunch of vector draw/fill commands. The first few AGI games showed that process happening; and, as a little kid having one of their first encounters with a computer, I found it fascinating to watch. Later games drew it in an offscreen buffer and showed it all at once, which looked more "professional" but took away some magic. Here's a video showing the drawing process: https://www.youtube.com/watch?v=v5DSFvWrNWA https://www.youtube.com/watch?v=v5DSFvWrNWA. Magic! EDIT: I had an agent make a guess and it came up with reasonable looking numbers that said an RLE bitmap would be a small handful of times larger. But it also interestingly pointed out that the vector commands encoded priority (i.e., what you can walk behind/through) whereas that'd have to be a second data set for a bitmap approach.
      - WorldMaker 1mo ago
        The vector art also included some complex dithering patterns that balloon RLE-encoded bitmaps. Dithered drawing is actually one of the worst cases for simple, pure RLE. For dithering compatible bitmap encoding you would want other more complex compression schemes than simple RLE. Some of the palette-based compression techniques of "modern" GIF were reused from such early predecessors, even though there's a belief today that RLE was most of what games at the time used. (It's useful to point out that early AOL was also heavily dithered, especially in monochrome versions. AOL also spanned the gap between dithered, heavily palette-based graphics to "early modern graphics".)
    - kolanos 1mo ago
      Yes, this is correct. I have a distinct memory of playing Space Quest (forget if I or II) on a CGA monitor and then seeing it on my friend's EGA monitor and being blown away.
- noufalibrahim 1mo ago
  I think the first instance of games being separated from the "engine" so that you could make the game and it would run on all platforms that the engine ran out without porting was Infocom's Z-machine. http://maher.filfre.net/if-book/if-4.htm http://maher.filfre.net/if-book/if-4.htm There was an interesting article which I read a long time. It's linked to from the post above called "How to Fit a Large Program into a Small Machine" published in 1980. AGI, SCI, Scumm etc. were all larger and more capable versions of this.
  - anthk 1mo ago
    Also, a micro Inform6 compiler+library: https://github.com/johanberntsson/PunyInform https://github.com/johanberntsson/PunyInform Tristam Island as an example: https://github.com/hlabrand/tristam-island https://github.com/hlabrand/tristam-island
    - gapan 1mo ago
      Also, ozmoo, a z-machine interpreter for the C64 (+other 8-bit machines) with several qualify of life improvements. https://github.com/johanberntsson/ozmoo https://github.com/johanberntsson/ozmoo https://ozmoo.online/ https://ozmoo.online/
  - WorldMaker 1mo ago
    Z-Machine is also useful to point out because it's one of the clearest lines to draw from it to the modern JVM and .NET CLR. Whereas AGI/SCI/SCUMM all have very game specific virtual machines, Infocom's was Lisp influenced and even built it with business/enterprise apps in mind, though Infocom's one attempt at doing exactly that with their database app Cornerstone was a market flop. (It's heavily enhanced fork of the Z-Machine was also only released for a fraction of the machines the game Z-Machine supported.) I still think it's an interesting question if Infocom had not tried to keep the Z-Machine proprietary "secret sauce" if it would have been a larger platform of general computing for much longer and broader than Infocom's own lifespan and primarily games focus. If Infocom had taken a Sun-like stance on the Z-Machine being a JVM ahead of its time and building a broader compatibility ecosystem "write once, run everywhere" might have been an earlier part of computing.

songhonglei1985 1mo ago

[dead]

trollbridge 1mo ago

The fusion of "64-bit architectures" and "64K total RAM machine" brings a bit of a smile to my face with projects with names like this.

JoshTriplett 1mo ago

The only good AGI. Impressive fitting into the machine. I wonder if SCI would be possible?

bzzzt 1mo ago
Only with some serious downgrading of the assets. I remember playing SCI games on an 8MHz XT class PC and everything ran dog slow. Some SCI games had optional animations that didn't play on a slow machine.
stuaxo 1mo ago
Now this is an AGI I can get behind.
aidenn0 1mo ago
AGI was an impressive game engine. It's just a shame it was wasted on so many bad games.
- JoshTriplett 1mo ago
  Some of them weren't wildly worse than the era. I think many old games substituted punishing difficulty for depth, so that they'd have more staying power. That was true of some of the early NES games as well.
  - aidenn0 29d ago
    I agree that they weren't terrible for the era, but they weren't great either. I'll pick on SQ1, since that's the highlight of TFA. Obtaining the Jetpack is not just punishingly difficult, even once you get to the point where you know you need a jetpack there are zero hints where you might obtain one; the only solution is to replay the game and try random things differently than the first time you played through.
    - JoshTriplett 28d ago
      Yeah, agreed. Many games did the same, but that didn't make it good. On the "cruelty scale", that'd be a "Cruel", since it has a "walking dead" state of "you did it wrong a while back and have to start over": https://eblong.com/zarf/essays/cruelty.html https://eblong.com/zarf/essays/cruelty.html (and https://eblong.com/zarf/essays/cruelty-revisited.html https://eblong.com/zarf/essays/cruelty-revisited.html ) Early King's Quest games were in that same category of "Cruel", where an incorrect choice is not immediately obvious as a mistake. I think King's Quest V was closer to "Nasty" (because it can catch you off guard with things you fail, but it'll be obvious that you did something wrong). But there are a couple of exceptions that keep it in "Cruel", though: you can eat the wrong item when you're starving, and in some cases if you miss picking up an item you can't go back for it, so if you didn't see it at all then you have to go back to an earlier save. That one definitely required keeping a full array of save files. (Very satisfying to complete, though.) Even King's Quest VI, which is much more forgiving, has some cases of "you need the right item before proceeding into this section you won't be able to leave (for a while)". But it goes out of its way to advertise those "points of no return", so I'd rate it firmly at "Nasty" rather than "Cruel", with the asterisk that there are ~3 notable points where you might have to go back by more than just your most recent action, but it'll be obvious you want save points at those points to go back to if you find you can't progress inside. (Before the catacombs, before the land of the dead, before entering the castle.) The entry to the catacombs even offers you the chance to go prepare further, if and only if you don't have everything you need.

TMWNN 1mo ago

Excellent! Five months ago I wrote about why Sierra never released AGI games for C64; it was not technical so much as market focus. <https://np.reddit.com/r/c64/comments/1r8hgwk/kings_quest_i/o670li7/?context=3 https://np.reddit.com/r/c64/comments/1r8hgwk/kings_quest_i/o...>

madhu_ghalame 1mo ago

[dead]

hn974izqdv 1mo ago

Simple advice, hard to follow

vkaku 1mo ago

We finally achieved AGI outside these AI companies on portable home computers

mromanuk 1mo ago

I know what is AGI, I read the queues Adventures, Sierra, should be obvious where this lead. But my mind went to "oh, thanks to LLM coding agents, they massively ported every Sierra Adventure to C64".

pimlottc 1mo ago
*cues

1970-01-01 1mo ago

>Made for a 1 MHz machine That's impressive work. It's fun to think how today's CPU rounding errors can run hit adventure games. Your smartwatch uses more cycles to render the time.

just60sec 29d ago

[dead]