Monday, 22 May 2017

Galaxy Trek Adventure #1

Galaxy Adventure #1
I have already ported Howard Batie's second Star Trek themed text adventures for the Coco to the MC-10. The Coco program for his first adventure, which can be found in Hot Coco Magazine August 1983, was based on an original game for the TRS-80 16K by Randy Hawkins in 80 Micro (August 1982, pp. 174-184). In fact, the version I ported might be more akin to Mr. Hawkins' original, as I based it on some source code that I found for the TRS-80 Model 100, which might have come from the Model I version rather than the Coco version.  However, the fact that Batie's name is on it leads me to believe that it must be from the Coco version. I have source for the Hot Coco magazine version, but it's from OCR text of a scan of the article, and it was getting very tedious trying to get it into running form, so I switched to the source for the TRS-80 Model 100. I might still plunk away at the original magazine source, because Mr. Batie suggests in the article that there are some differences between his version and the TRS-80 Model I version, which might be nice to uncover. Also, the magazine version uses the technique of encoding all of the messages, so you can't cheat by looking at the source code.

There were a number of errors in the Model 100 source. Some of these problems are outlined in a Gaming After 40 blog post. I found others and corrected them. There was a big problem with how the game handled the button pushing for the impulse engines, that essentially allowed you to correct the orbit without having to solve the puzzle. GamingAfter40 suggests that the way to get rid of the Klingon guarding the Tribble on level 2 is to get the phaser, but really it was because he pushed the button for the engines on level 1 and triggered the bug (which moves the guards to the planet). The real way to get rid of the guards is to shoot all of them with the phaser. The phaser only self-destructs on the planet after you've done all the necessary shooting on the ship. There were also problems with beaming routines, that allowed you to beam down without Spock being present, but which indicate that he is present by the messages displayed. There were also some problems with how the score was accumulated.

I have bug tested the program pretty extensively and played it to completion a number of times. Here's a play-through for those who may have been frustrated by the game in their youth.


** SPOILER ALERT **

G A L A X Y
A D V E N T U R E    # 1

COPYRIGHT 1982 HOWARD BATIE
HERNDON, VA 22070

NORTH,WEST,NORTH,DOWN,SOUTH,EAST,EAST,GET NEEDLE,WEST,WEST,NORTH,DOWN,SOUTH,WEST,NORTH,WEST,GET PHASER, GET COMMUNICATOR,EAST,SOUTH,EAST,EAST,FIRE PHASER,EAST,INJECT SPOCK,WEST,WEST,NORTH,UP,UP,SOUTH,WEST,FIRE PHASER,WEST,GET TRIBBLE,DROP NEEDLE,EAST,EAST,NORTH,DOWN,DOWN,DOWN,SOUTH,EAST (IGNORE SPOCK'S REMARK), EAST,THROW TRIBBLE,GET TRIBBLE,EAST,HELP,SAY TRISAETI,HELP,WEST,WEST,WEST,NORTH,UP,UP,SOUTH,EAST,NORTH,FIRE PHASER,EAST,GET MANUAL,WEST,SOUTH,WEST,NORTH,DOWN,DOWN,SOUTH,EAST,EAST,EAST,READ MANUAL,WEST,WEST,WEST,NORTH,UP,SOUTH,WEST,NORTH,WEST,GET SHUNT,EAST,SOUTH,EAST,NORTH,DOWN,SOUTH,EAST,EAST,EAST,INSTALL SHUNT (A GREEN PANEL LIGHT GLOWS...),WEST,SOUTH,READ MANUAL (NOTE: INSTALL CRYSTALS),NORTH,WEST,WEST,NORTH,UP,UP,UP,SOUTH,EAST,EAST,SAY ENERGIZE,FIRE PHASER,GET CRYSTALS,DROP PHASER,DROP TRIBBLE,DROP MANUAL,SAY ENERGIZE,WEST,WEST,WEST,WEST,GET TRIBBLE,EAST,EAST,NORTH,DOWN,DOWN,DOWN,SOUTH,EAST,EAST,SOUTH,INSTALL CRYSTAL (STARTS A COUNTDOWN),NORTH,WEST,WEST,NORTH,UP,UP,UP,UP,EAST,EAST,PRESS BUTTON (STABLE ORBIT ACHIEVED),WEST,WEST,DOWN,SOUTH,EAST,EAST,SAY ENERGIZE,GET PHASER,DROP COMMUNICATOR,EAST,NORTH,FIRE PHASER (PHASER VAPORIZED),NORTH,THROW TRIBBLE,EAST,WEST,SOUTH,SOUTH,WEST,GET COMMUNICATOR,SAY ENERGIZE

I also completed the clean up of two simple programs taken from OCR text of scans from Color Computer Magazine and Hot Coco Magazine. The first is a simple game called SPRINKS the second is a Mother's Day graphic and simple music demo called MOTHER:


Thursday, 11 May 2017

4 Mile Island Adventure: Update



4 Mile Island Adventure, not to be confused by another Basic adventure for a recent programming contest (in the 2000s) of the same name, was a text adventure made by Owls Nest Software for TRS-80 Color Computer and MC-10 in 1983. Ported the Coco version to MC-10. Made some changes in the save game routine. In addition to the object list of locations, it now also saves the following variables:
F,G,CF,TB,GB,CA (# of objects being carried), RT (reactor temperature), YO (present location), DO,NOT,DR,M
This means that you don't start fresh every time you save and re-load a game, which makes the game more challenging (as there is a countdown to meltdown).

Brief Outline:
The 'impossible' has happened! This area was devastated by a severe earthquake. The reactor has been severely damaged. The plant has been deserted. Only you can save the area from a major disaster! Your goal is to achieve a cold shutdown of the reactor at Four Mile Island. Alternative? Death!

Walkthrough:
S, E, E, S, S, LOOK DESK, UNLOCK DRAWER, OPEN DRAWER, LOOK, GET BADGE, DROP KEY, N, N, N, N, LOOK WALL, INSERT BADGE, LOOK, D, W, GET CROWBAR, GET WRENCH, E, U, S, E, LOOK FLOOR, MOVE TILE, LOOK, DROP CROWBAR, GET ID, W, N, N, N, D, GET SPANNER, U, S, S, E, N, PUSH BREAKER, N, PUSH BREAKER, S, S, W, S, E, DROP WRENCH, GET CROWBAR, W, N, E, OPEN VALVE, W, PUSH SWITCH, PUSH LEVER

Type CLOAD & hit ENTER. Select TOWER.​C10 in the JimG subdirectory of the Cassette directory. Type RUN...

Sunday, 30 April 2017

RetoChallange 2017: Graf Spee


Came across a neat game for the Sinclair ZX81. It's a World War II naval simulation. You play the role of the captain of the German battle cruiser the Admiral Graf Spee. You must destroy shipping and avoid being captured or destroyed. I have't got it working quite yet, but I have made substantial progress.  Here are some screens showing a little of what the game will look like.




 I still have to finish converting all the lowres graphics for all the ship types.

This is likely my last posting for RetroChallenge 2017. Thanks to John for organizing another competition for this year. Thanks to all the other posters. I'm still working through browsing all the projects. They are wonderful inspiration for further efforts in my own retrocomputing hobby activities. Good luck to everyone and I hope to see you all again next year!

P.S.

Here's a video of the completed game:

Monday, 24 April 2017

RetroChallenge 2017: 4 Mile Island Adventure



Found another obscure adventure in the TRS-80 Color Computer Archive. This one's called 4 Mile Island Adventure. It's loosely based on the 3-Mile Island nuclear disaster. Everyone has fled and it's up to you to cold-shutdown the reactor.

Couple of weird things about the adventure. First the save routine seems to just save the objects array. It doesn't appear to store anything else, such as your location, the reactor temp, radiation level or how many items you're carrying (although this may be generated when you take an inventory).  So when you restore, you seem to start off at the beginning location, but you have any items you found previously.  Since you are racing against the reactor temperature going up, it seems like you can reset the clock by saving.  Don't know if this is important or unimportant, but I might change it.

There is a link in the archive to the manual by Owls Nest software. I can't find a link to the game in the CASA: Solution Archive, although there is a listing for a program of the same name written for a recent text adventure contest.

Since there's no listing, I'm working on solving it.

Friday, 21 April 2017

Retro Challenge 2017: Greg Hassett Adventures

I have finished porting two Greg Hassett adventures. "Atlantis" was ported from a Coco version. It was very buggy and the screen formatting was very weird. It also lacked save and restore routines. So I had to go back to the TRS-80 16K version and put them back in based on what I found in that source code. I have played it through using a walkthrough, so I hope it is pretty much bug free now.


I also ported "Enchanted Island." I used source from TRS-80 16K source. Working on Atlantis had prepared me well for Hassett's programming style, so this conversion went very fast.


After completing these two adventures, I realized from internal advertising that Hassett displays in them that he had set of adventures.
59000 R1$="TRY SOME OTHER GREG HASSETT ADVENTURES: JOURNEY TO THE CENTER OF THE EARTH, THE HOUSE OF SEVEN GABLES"
59005 R2$="KING TUT'S TOMB, SORCERER'S CASTLE, VOYAGE TO ATLANTIS"
These messages get displayed at various occasions, such as when your character reads a newspaper, or at the end of the game. I realized that I had previously ported the others. So I went back and fixed them up to use a common visual aesthetic (eg. solid line demarcating main messages from input prompt). Now I have a set of six Hassett adventures:
  1. Voyage to Atlantis (ATLANTIS.C10)
  2. Sorcerer's Castle (SORCAST.C10)
  3. King Tut's Tomb (TUTSTOMB.C10)
  4. Enchanted Island (ENCHANTI.C10)
  5. The House of Seven Gables (GABLES.C10)
  6. Journey to the Centre of the Earth (JOURNEY.C10)

The House of Seven Gables

Journey to the Centre of the Earth

Sorcerer's Castle

Tut's Tomb with my own intro screen
They can all be found on my distro: http://faculty.cbu.ca/jgerrie/Home/JG_MC-10_GAMES.zip

Sunday, 16 April 2017

RetroChallenge 2017: Dr. Livingston Adventure


I noticed a BASIC adventure "Dr. Livingston: The Search For" listed on Curtis Boyle's site. I have searched through many Coco archives, but I couldn't recall every seeing a copy of this game. I also found a listing for it under Gaming after 40 blog. It sounded like an interesting game, that was having a little fun with the famous story of the search for Dr. Livingston, who disappeared into the heart of Africa in the early period of European contact with that continent.

I also found a listing for it under the Interactive Fiction Database. The reviews were't very good, but I think this was because most people had played an unofficial version of it for the Commodore 64 that was a little buggy. Here's what I said for a review I wrote for the the database:
I have read the other reviews and can't but wonder whether some of the frustrations result from the versions they are playing. The parser is not so problematic in the TRS-80 versions of the program. These machines often ran in all caps mode (the original TRS-80 didn't have uppercase characters and the TRS-80 MC-10 never had them). Apparently there were also changes made to the puzzles in many of the unofficial versions. The TRS-80 version I ported remains entirely true to the original TRS-80 16K version.

There are some intentional inconsistencies to the movement in the game. I didn't find them all that bad (especially compared to some other games from the era). For the most part I think they were carefully chosen and meant to enhance the effect of being "lost in the jungles and savannas" of central Africa. To a large extent, I think this technique works successfully in this adventure, where the setting makes it appropriate to use. Once I had some mapping in place, it wasn't all that problematic and there is a kind of logic to the backs-and-forths.

There are some really charming aspects to the game. The quicksand graphic is a wonderful piece of TRS-80 chunky pixel 8-bit animation. If you die the program simulates a return to the basic command prompt, before surprising you with a resurrection to a restore point part way into the game (preventing a need for a complete restart).

The game is challenging and doesn't have any of the totally arbitrary deaths that are so common in games from this genera. I found the plot to be a nice balance between slightly humorous almost fantastical whimsy and an attempt to remain true to the Victorian mythology of the original quest for Dr. Livingston.

For fans of 8-bit Basic adventuring I would highly recommend this game. But for less hardy souls, it might be better to stay away from venturing into the dark heart of the Victorian imaginary.
I had asked if Curtis could put his hand on his copy, but it sounds like he's buried under a pile of original disks. He said he'd keep his eyes peeled. In the meantime, I put my hands on the original TRS-80 version of the source code and over Good Friday and this Easter Weekend I plunked away at converting it to Micro Color Basic. I don't think I have ever come across so many convoluted long IF-ELSEIF lines before. Some took a number of different stabs at it before I got them right. The really fun part was re-creating the graphic for the jumping character animation.

I ran into some snags at the end in the form of some strange behaviour with FOR/NEXT loops.  I think this might have been a result of the fact that like a lot of early programmers the author of this game use a lot of FOR/NEXT loops for searches which they exit ungracefully from the middle of using a GOTO statement when they find what they're looking for.  I always try to properly finish a FOR/NEXT.  Anyway, I fixed a few of these and started using my own variable for my additions to the program to avoid conflicts with the FOR/NEXT variables used in the original.  Another, difficulty with porting was the use in the original TRS-80 16K version of IF structures like this:

IF A<B GOTO 10
or
IF A>B LET A=0

It's possible in original TRS-80 Basic to dispense with the THEN command.  In Micro Color BASIC this can only be done using the GOTO command. Others, like LET don't work.  Had to weed all these out.  Also the programmers had used DEFSTR to define a bunch of character string variables without dollar signs, another feature missing from Micro Color Basic. I think it is fully debugged now.  I have played it through to its end a number of times and in a number of ways.  Here's a vid of LIVNGSTN.C10. At the end of it you can see the effect of the fake "exit to Basic prompt" before it revives you to a restore point.  Very clever little effect that demonstrates the care lavished on the game by its original programmers, Carl Russell, Karen Russell, Ralph Fullerton, Becky Fullerton. (published in Softside, Vol. 2. no 12):



Thursday, 13 April 2017

RetroChallenge 2017: Tackle Penguin


Someone besides myself finds it interesting to scan through old Japanese Basic computer magazines looking for code to convert to an 8-bit computer with a Motorola MC6847.

Emerson Costa shared the following post on facebook:
A video of mine describing my odyssey in converting a type-in BASIC program found in an old Japanese magazine (1988), originally for Fujitsu FM-7/77, to my Brazilian CCE MC1000, based on CPU Z80 & VDG MC6847 & PSG AY-3-8910.
It's in Portuguese, but here is an abstract:
I describe the game mechanics and rant about some of the FM-7/77 BASIC instructions that write text and stamp images on the graphic screen.
I talk about how game logic is mixed with interface logic, and give an example of how I separated those things in my conversion (reading keys from the keyboard vs getting commands from the player).
I show a first version in text mode, and then go on to make it graphic (using MC6847's Resolution Graphics 6, which is set by MC1000's HGR instruction). Machine language comes into stage with routines to draw 8x8 characters/sprites on graphic mode, and remove keyboard beeping. A final section of the BASIC program is added to POKE the corresponding bytes into memory.
Sound is still lacking. The original program uses the PLAY instruction, MC1000 has TEMPO & SOUND instead. I studied them all instructions and came up with an HTML page with JavaScript code that translated PLAY strings into a series of SOUND commands.
Then the conversion is complete. Oof! 😅It should be easy to adapt the program to MC-10?
Emerson was very generous to provide some further conversion advice:
Some machine-specific info:
CALL 49158 -- Waits for a key to be pressed and released.
POKE 910,0 -- Avoids an annoying behavior of PRINT, just ignore it.

PEEK(483) -- ASCII code of last key pressed.
PEEK(485) -- 255 if a key is pressed; 0 if none.
POKEs after HOME -- Makes cursor invisible. Ignore.
POKEs at the end of program -- Machine code routine related to keyboard reading. Ignore.
The CCE MC-1000 is an interesting machine. It's got the screen of a Coco, the keyboard of an MC-10, and the Basic of an Apple II. It's a totally unique hybrid. The Brazilian government really fostered some interesting creativity in 8-bit computers with its protectionist policies. Anyway, with Ensjo's help I was able to get a version working for the MC-10.
Your penguin is an A
It's able to jump in the following ways:
                       A  to here
                       
It can jump from here  A  up through the block (using the W key jumps straight up).
It can jump up and left or right using the Q and E keys.
             A to here using the E key         A  to here using the Q key
from here  A ■               or                ■  A  from here
You can also push blocks left and right if there is only one and there is open space for it to move into. Blocks don't fall if you push them off other blocks. But you will fall if you jump off a block.  Some weird physics, but it makes for a neat puzzle. I still haven't solved puzzle 1 yet, so the game has yet to be fully bug checked. If there are any puzzle fanatics out there who solve it, let me know.  I'll put the game up as it currently is in my distro:

The following is an update of my original attempt, with improved handling of the move sound and music interludes (I hope):



And here are some further updates to messaging and a demonstration of the Win music routine: