Text adventures

bokvamme · Post by **bokvamme** » Wed Apr 22, 2009 2:04 pm

Or maybe replace the text crunch routine with a better one to fit it all into memory. I haven't seen the code and therefore don't know how they encode the text. I suspect the text is the part of the game that takes up the most space.

Post by **Jeff-20** » Wed Apr 22, 2009 9:58 pm

vic user wrote:you are a genius Carlsson!

Ditto!

carlsson · Post by **carlsson** » Thu Apr 23, 2009 12:16 am

Bah, just posting wild ideas doesn't make one a genius. When you have proven it indeed works, I will accept the status.

nbla000 · Post by **nbla000** » Thu Apr 23, 2009 6:39 am

carlsson wrote:Do you see where I am aiming? Yes, if the engine from e.g. Pirate's Cove could be reused to play one of the latter adventures, we'd get at least a half dozen new adventures for the VIC-20.

Nice, I don't like this game genre but i like the idea

carlsson · Post by **carlsson** » Thu Apr 23, 2009 7:25 am

I asked TNT, and he estimates the actual V3 parser to be 7K + 2K workspace data. It might be possible to trim a bit more, but would make the game run slower.

The rest of the memory thus is used by the dictionary, locations and all the other game data. It does sound promising, although it was pointed out that the small VIC-20 display would result in a lot of scrolling and prompts to press a key.

ral-clan · Post by **ral-clan** » Thu Apr 23, 2009 4:25 pm

Since everyone who owns a MegaCart will have a 32K expander and 40 column emulator, maybe a version could be made that would run under that configuration (yes, getting ahead of things here).

I also assume that the standard version being mostly text, would run pretty much unchanged on a VIC with a 40/80 column board.

carlsson · Post by **carlsson** » Thu Apr 23, 2009 6:13 pm

The software 40 column emulators however steal quite a bit of memory so if 32K on a 40 column PET is a bit tight, I think the Infocom adventures would be best played on a standard 22 column screen. Perhaps change 36866 to 26 columns or how many are generally visible on a real VIC-20.

ral-clan · Post by **ral-clan** » Thu Apr 23, 2009 8:27 pm

carlsson wrote:The software 40 column emulators however steal quite a bit of memory so if 32K on a 40 column PET is a bit tight, I think the Infocom adventures would be best played on a standard 22 column screen. Perhaps change 36866 to 26 columns or how many are generally visible on a real VIC-20.

Oh, I was thinking that if the 40 column emulator was running from a cartridge (on the Mega-Cart) it would somehow not occupy any of the VIC's RAM (unlike when you load a 40 column emulator from disk). I guess I don't fully understand how images "load" from a cartridge (i.e. are they actually run "straight" off the cartridge, or is the image first transferred to the VIC's RAM, then run?).

carlsson · Post by **carlsson** » Fri Apr 24, 2009 1:25 am

Well in the case of the 40 column program it defines a high resolution screen similar to the ones used by those picture viewers. Then it plots the smaller characters on the screen, so a couple of kilobytes of "system RAM" gets used up by the graphics. Perhaps not all 4K of it.

In this case, the Sentoria text reader may be a better option. It only defines as many custom characters as required, so combinations of letters used multiple times will only take space for one.

<off-topic>
Of course a hardware 40/80 column card puts things into other perspective but those are not really common. If anyone would re-engineer new ones and add some bank switching RAM expansion on the same card, you could probably make a nice "text adventure computer" out of the VIC-20, given you have this kind of expander. I don't know how big the demand would be for a 40/80 column + REU expansion. Ideally the graphics chip would be something with colours, custom defined graphics, sprites, perhaps S-Video or RGB output. Not that your typical Infocom adventure requires that stuff, just in order to broaden the usage.
</off-topic>

ral-clan · Post by **ral-clan** » Tue Apr 28, 2009 11:35 am

Guess what I did last evening? (well, Carlsson knows).

I played Zork I on my real VIC-20 with a beta version of a Z-Machine interpreter developed by Jorma Oksanen! (I am a beta tester)

He gave me permission to report this news here....however, the binary is still in development and cannot yet be distributed (however it works very well from what I have seen).

It really was not bad at all in 22 columns! Much better than I expected. I rarely had to press the <MORE> key. Also, the game was about as fast as I remember Infocom games being on a Commodore 64 (and Jorma is going to make it even faster before it is released).

This is a great time for the VIC-20!

The Mega-Cart acted as my 32K+3K expander to make this possible!

orion70 · Post by **orion70** » Tue Apr 28, 2009 11:29 pm

I have no words... When will it be ready? Will it be free? Any more info on that?

carlsson · Post by **carlsson** » Wed Apr 29, 2009 12:31 am

I'm happy things worked out. If I understand correctly, the game while running uses about 38.25K RAM, not counting the colour matrix? That would make it one of the largest VIC games ever.

ral-clan · Post by **ral-clan** » Wed Apr 29, 2009 5:20 am

I thought there would have been more excitement about this other than myself and Orion70. Infocom adventures on the VIC-20!

But I guess text adventures have a limited audience.

But from a technical standpoint this is a major achievement (formerly thought impossible).

Anyway...to partially answer your question: I'm not totally sure how much RAM it takes (Jorma said something about there being 77 bytes free and I know one must have the 32+3K expander active to run it). But Jorma also said that certain adventures could probably run in 16K+3K but that they would be very slow.

How do you come to the total of 38.25K Carlsson? I thought the maximum memory the VIC could be expanded to is 32K+3K (which to me adds up to 35K)?

I wonder if Jorma knowns about the tape buffer memory being available and/or is also using some or the RAM in the 1541? He's pretty much a programming wizard so I doubt he would be ignorant of these things.

Mike · Post by **Mike** » Wed Apr 29, 2009 5:37 am

ral-clan wrote:How to you come to the total of 38.25K Carlsson? I thought the maximum memory the VIC could be expanded to is 32K?

BLK0, BLK1..3, and BLK5 can be populated with RAM. I/O2, and I/O3 also could hold 1K RAM each. This amounts to 42K RAM. BASIC needs continuous memory, restricting the size of a BASIC program + its variables to 27.5 K.

I wonder if Jorma knowns about the tape buffer memory being available and/or is also using some or the RAM in the 1541?

There are also the 1024 nibbles of colour RAM, of which normally the half is not displayed, and could be used for other things. And the program redirect area from 673 to 767.

But before I use dedicated buffers, I'd rather use uncommitted memory - preferably whole bytes. And accessing the spare memory in the floppy drive quite possibly adds more overhead, memory-wise, in the computer, than it's going to make available for the VIC - and access would be rather slow.

Michael

orion70 · Post by **orion70** » Wed Apr 29, 2009 5:57 am

Maybe people did not understand what's going on here...

Z-Machine Interpreter is being ported to the VIC-20!
The following adventures are only a small part of the ones that can be played within it:

Adventure (aka Colossal Cave)
Adventureland
Buckaroo Banzai
The Count
Ghost Town
The Golden Voyage
The Hulk
Mystery Fun House
Strange Odyssey
Pirate Adventure (aka Pirate's Cove)
Pyramid of Doom
Return to Pirate's Isle
Savage Island
Secret Mission (aka Mission Impossible)
Sorcerer of Claymorgue Castle
Spiderman
Voodoo Castle

See also HERE for a partial list (437 ITEMS)

.