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Chasing the Dream: The Tribulations of a Bedroom Game Programmer

Chasing the Dream: The Tribulations of a Bedroom Game Programmer

Part II

Author and Multimedia: Nickolas Marentes
Editing: Bill Loguidice and Matt Barton
Online Layout: Bill Loguidice and David Torre
Special Thanks: Matthew Reed of the TRS-80 Emulator Web Site
Comments: Visit the author's Website or send an e-mail to nick@launch.net.au
Emulation Notes: Game ROM/image files have been provided within the article for four TRS-80 Model I programs. According to the author, presently, the best emulator to run these files is called TRS32, which is for Windows. The emulator is shareware and payment provides extra features such as hard drive and high resolution graphics support. These features are not needed to run these games. The emulator is almost 100% faithful to a real TRS-80, save for a small issue with timing where the title pages for these games seem to stay up for too short a time. Otherwise, the games run perfectly. Click the following system name for the required TRS-80 Model I and Model III system ROMs. While additional ROM/image files are not provided here, please note that none of the Color Computer emulators presently run Neutroid 2 correctly because they don't support the semigraphic video mode that that game uses. The games for the Color Computer 3 do not run correctly on any emulator except MESS. For these and other downloads, as well as to purchase some of the actual software, please visit the specific page on the author's Website.

Editor's Note: This article is part II in a series. If you haven't read part I yet, we highly recommend you do so now!

Neutroid 2 (1984, TRS-80 Color Computer)

I finally decided that it was time to leave the TRS-80 Model I and move into the world of high resolution color graphics. I had to update to a new market, but a sense of fear and uncertainty fell upon me. I was quite comfortable with the TRS-80 with its easy to use blocky monochrome graphics and powerful Z-80 CPU, but all good things must end, so I began to look around at what was available.

The Commodore 64 and Atari 800 computers appealed to me with their graphics and sound capabilities, but I knew it would be some time before I could create games that could compete with what was becoming available. I had to find a computer that was still in its infancy, yet had the potential to become a big seller.

The new MSX standard was coming out, and I liked the hardware architecture. I looked closely at two early MSX systems from Spectravideo and Sega, and I was impressed, but something inside of me said no. As time has now shown, my "gut feeling" proved right, and MSX didn't catch on very well outside of Japan.

Neutroid 2 Title Screen
Neutroid 2 Title Screen
Neutroid 2 Game Screen
Neutroid 2 Game Screen
Ironically, in the end, I went for a machine with lesser graphic and audio capability than most of the newer systems that I had evaluated. I chose the Tandy (Radio Shack) Color Computer (CoCo). The Color Computer line lasted until about 1991, outlasting many of the competing systems. I guess I was destined to be a Tandy man!

There were two things that attracted me to the Tandy Color Computer. One was that it had the most powerful 8-bit CPU, the brilliant Motorola 6809. The other was that it had a large distribution channel via the Tandy/Radio Shack company stores worldwide. Here in Australia there were over 700 stores country wide. I had always dreamed of tapping into that marketing. I figured that a game sold to Tandy Australia would guarantee 700 copies sold!

Story pretext...this one is verging on the realm of actually being good!...

"For centuries, man has strived for the ultimate power source. As fossil fuels become scarce, the need for a new, inexhaustible source of energy grows more and more.

But in a dimly lit laboratory, a professor is experimenting on a newly discovered sub-atomic particle. This particle has been named, NEUTROID and is causing great controversy in 'The Neutroid Project'.

A prototype power generator has been constructed. Inside this generator is housed a number of small lead/titanium boxes called Particle Vaults. Within each vault is a grid network along which Neutroid and Antitroid particles travel. Protroid particles and special maintenance units called Grid Chargers are adjacent. Monitoring of the particle vault is performed by external scanners creating a color coded image onto a standard color television screen.

In order to release the stored energy from within the vault, the Neutroid particle must be guided via electromagnetic fields into a collision with each Protroid particle at the same time avoiding the Antitroid particles which are attracted to the Neutroid's magnetic field. As the energy output of the generator increases, each successive grid becomes more difficult to complete. Therefore, lighting fast reflexes and rapid strategic thinking are a key element to the success of this experiment!

Science is counting on you professor! Complete each grid quickly before the particle vaults reach the meltdown state, else all is lost!

You have to admit, I'm starting to get better!

The Tandy Color Computer was quite limited in its graphic capabilities. In its highest graphic resolution of 256 x 192 pixels it could only display two colors. The choice was limited also, black and white with only a white border or black and green with only a green border.

The next resolution down was 128 x 192 in four colors. Again, a limited choice of colors - green, red, yellow and blue with only a green border or white, magenta, cyan and orange with only a white border.

You can understand why many of the games all had a similar look. In the US, a technique called artifacting was used to push a few extra colors in the normally black and white high resolution mode. The technique relied on the US NTSC video standard being particularly poor at color accuracy when alternating high and low contrast pixels are placed next to each other. This technique managed to coax a few shades of red, blue and yellow along with the standard black and white.

The problem with this technique was that it didn't work for the PAL video system as used in Australia. All we saw was an ugly striping effect of olive and purple that made the games look dreadful. I wanted to crack this limitation and I found it in the form of the Semi-Graphic modes. These modes allowed all eight available colors with a black border. The problem was that the horizontal resolution was dropped to 64 pixels and there was a color limitation that required each pair of odd/even pixels (byte boundary) to have the same color (or black).

I created Neutroid 2 to use this mode and designed the graphics to make best use of this limitation.

Neutroid 2 High Score Screen
Neutroid 2 High Score Screen
Neutroid 2 Packaging
Neutroid 2 Packaging
Sound was another area I wanted to improve on over other games available for the TRS-80 Color Computer at the time. Unlike many of the other systems on the market, the Color Computer didn't have a dedicated sound chip to do this and required the CPU to feed the audio data to the output port. The Color Computer generated sound using the same method as the TRS-80 Model I by toggling a voltage via CPU intervention on/off to create sound waves. However, it was a bit more advanced in that it could vary that voltage up to 64 steps instead of the two that the Model I had. In other words, it had six bits available instead of two for sound generation. I could actually make a sound fade off and create effects with more realistic sounds. This ate into the time required for graphics, but this was a challenge that I had largely overcome in the TRS-80 Model I and I included the same techniques on the Color Computer, but using its six bit capability I felt that this game couldn't fail, and I began dreaming of that luxury Porsche in my garage.....

Well guess what... It was a flop.

I got daring with Neutroid 2, taking out a half page advertisement in an Australian color computer journal called Australian CoCo. Nothing came of it, no sales. The only sales I made were achieved by demos at club meetings. Neutroid 2 seemed to suffer the same fate as the original Neutroid; the game was too abstract in concept people didn't get it. I had to address this problem and get smart with my distribution. It was clear to me that the time had come to knock on Tandy's door, but first I needed a game that they couldn't refuse.

I was a game programmer on the edge and I was determined to succeed!

Donut Dilemma Title Screen
Donut Dilemma Title Screen

Donut Dilemma (1986/7, TRS-80 Color Computer)

I wanted a game good enough to be sold by Tandy in all their stores Australia wide, so I decided to port my best TRS-80 Model I game to the Tandy Color Computer and submit it to Tandy Australia with the hope they would add it to their stock line.

Donut Dilemma had the advantage of having a more familiar platform style of game play than Neutroid 2. Other successful games such as Donkey Kong, Lode Runner and Miner 2049er proved that this genre was popular internationally so I began programming with the hope that this game would finally offer me some success worth talking about.

Story pretext....

"Angry Angelo has raided Antonio's Donut Factory sending the entire complex amuck! Donuts have come alive and are jumping around in wild frenzies. Machines have gone out of control throwing cooking fat, dough and icing sugar everywhere. You must help poor Antonio climb ladders, jump platforms and ride elevators to reach the top floor and shut down the factory's power generator which will restore law and order. "

Kind of looks familiar don't you think? Yep! Ripped it straight off the TRS-80 Model I version.

donutcc/Level 1.gif
Donut Dilemma - Level 1
Donut Dilemma - Level 9
Donut Dilemma - Level 9
This was my first game that used a true high resolution color graphics mode on the Color Computer, and I was concerned it would be too difficult for me to achieve. Being accustomed to manipulating a mere 1K screen display on the TRS-80 Model I, I was wondering if the game would be fast enough writing it for the 6K screen display I was going to use. I ploughed on and hoped for the best.
Donut Dilemma Screen - After All 10 Levels
Donut Dilemma - Final

Following on from my desire to beat the color limitations of the CoCo, I devised a way of pulling more colors than was normally available. I couldn't use the US artifacting trick, so I began experimenting with the 128 x 192, four color modes to see if I could fool the TV to display extra colors here under the PAL video system.

I discovered that by placing horizontally alternating lines of magenta and orange that the television output (the Color Computer only had a TV output) would display red. Also, alternating horizontal bands of magenta and cyan would create a light blue. I created Donut Dilemma to use this new capability giving the most colorful display I had seen in a Color Computer game... six colors!

Later I had to remove this feature due to the new Color Computer 3 being released with an RGB monitor, which didn't allow this color mixing trick to work.

I added an extra level in the Color Computer version that was not included in the TRS-80 Model I version. Level nine was titled "Crumble Caper," and when the player first starts the level, it appears quite straight forward... except that as he/she steps on a platform, it begins to crumble beneath their feet and they only have just over a second to jump to another part of the flooring before they tumble to their doom. There is practically no chance to stand still! This is my favourite level, and it is not so difficult once one works out its simple solution.

Now here is an interesting story...

After completing the game and attempting to sell copies via the usual channels of computer clubs, I finally drummed up the nerve to send a copy to Tandy Australia's head office. I felt the game was good, if not better than many of the games they were already selling, but I kept my expectations low. In the past, all games except for a few educational titles were imported from Tandy Corporation's main warehouse in the US. That seemed to be where most of the decisions were made as to what became the product line.

It was around mid 1987 and Tandy had already released their new Color Computer 3 about 10 months earlier, an enhanced version of the older model that had been selling for 6 years. It had better graphics and a faster CPU. I had purchased one as soon as it became available. I was concerned that Tandy may reject my game due to a possible new focus of only considering games that utilized the features of this new model.

Donut Dilemma Worksheets
Donut Dilemma Worksheets
Then came the big surprise! I got a phone call saying that they liked the game and were interested in marketing it in Australia. The conditions were that I supply a complete package of color artwork, instructions and cassette tape. They also asked for a version enhanced for the new Color Computer 3. We made a deal that I supply both versions on a tape. They would buy it for $6.90AU a package and pay for the freight from my home to their warehouse.

Well, the profit margin wasn't huge, only about $3AU per package, but it was a start in the right direction, so I accepted. The first order to come in was for 1000 complete packages and I shipped them on the fifth of August, 1987. They even supplied an official Tandy catalogue number... CAT. NO. 26-9649. I was in!

Donut Dilemma Packaging
Donut Dilemma Packaging

Now here is the really interesting part. I later found out that the local magazine, Australian CoCo, was holding a competition in conjunction with Tandy for the best game submitted written for the new Tandy Color Computer 3. I didn't know about the competition. When I submitted my game to Tandy, it was soon after the competition had closed and they had chosen a winner. The winner got their entry added to Tandy's product line and more importantly, bundled with the Color Computer 3 in a special Christmas package.

My game missed the competition and wasn't written to exploit the new computer's features, yet they added it to the product line as well as the special Christmas package! It even appeared in Tandy Australia's annual product catalogue. That's what I call luck!

After the first 1000 copies, Tandy followed it up with another order and another order. In the end, 3400 copies were sold a vast improvement over my previous attempts. I knew that my next step was to create something specifically for the new Color Computer 3.

I had a fire burning within and I was aiming for a checkmate!

Rupert Rythym (1988, Tandy Color Computer 3)

After the success of Donut Dilemma for the Tandy Color Computer, I immediately went to work on another game. This time it was to be a game specifically for the new Color Computer 3 to exploit the enhanced graphics and speed of this machine. There was no need to develop tricks to create extra colors. The new machine could display 16 colors selectable from a palette of 64. It had a higher resolution of 320 x 225 pixels (or 640 x 225 in four colors) compared to the old model's 127 x 192 pixels in four colors (or 256 x 192 in two colors).

And once again I chose a platform style game. I wanted to add more of a puzzle element to the game and came up with the following plot...

"As tired as he was, the loud ringing sound could not be blocked out by his phenomenal level of exhaustion. Slowly, he opens his eyes and pushing his remote percussion keyboard aside, proceeds to answer the phone.

'"Rupert! Wake up!" frantically cries Rupert's manager, Bill Boombox.

"Hardrock Harry, manager of Music Box Records has stolen all your musical manuscripts and plans to release YOUR song under HIS name!!! Your entire future is at stake! Get those manuscripts back! Fast!!" CLICK!

You must help Rupert infiltrate Music Box Records and collect all his stolen notes which are scattered throughout the complex. Ride the crazy elevators and beware of the security robots on patrol. After collecting all the stolen notes, you must work out their correct sequence before Rupert can perform his first live concert which will lift him to international fame and fortune!

You have to admit, that was a pretty good storyline!

Rupert Rythym has nice graphics. I used nice metallic shading on the elevator poles and platforms to give a slight 3D look and Rupert himself looks and animates great! There is a lot of sampled sound used in the game from Ruperts "Hey!" to the various percussion effects.
Rupert Rythym Game Screen - Level 0
Rupert Rythym Game Screen - Level 0
Rupert Rythym Game Screen - Level 1
Rupert Rythym Game Screen - Level 1

This game uses the same techniques I had been using since the TRS-80 Model I games. The sprite animation engine was almost identical in operation and while the graphics looked very clean, no flickering, no jerky movement and all the moving objects (sprites) glided over the background elements perfectly, it was a bit slow. I had opted to move everything by pixel-pixel movements and when using a graphic mode that takes up 32K, proving to be a burden on the graphics engine. I was also still generating sound by the old method that I had been using and this also came with a speed penalty. I knew I had to update my graphic and sound routines in the future to better suit this new computer.

My personal opinion of this game was that I could have improved the gameplay a bit more. I feel that I concentrated more on the puzzle element and didn't give enough thought to the arcade game element. Apart from the game having a bit of a slow feel to it, I believe that there is also too much "standing around" on each screen as the player waits for the moving elevator to reach his platform. In hindsight, I should have made the platform move immediately to the player's platform rather than let it carry on in its fixed pattern of movement.

And no, the word "rythym" is not how we spell the word in Australia as a US review once stated. That was a real spelling mistake on my behalf. I take full responsibility! There, I admit it.

Rupert Rythym Packaging
Rupert Rythym Packaging

My excuse was that "Rythym" is a commercial twist on the word "Rhythm" used as Rupert's surname, his "fame name" if you like. Well... of course that's a crock of @!#?@! but I figured a small politician style lie won't hurt and I may even get away with it... I did! Nick for president?

With Rupert Rythym, I decided to go upmarket with the graphic artwork for the packaging. This time, I drew a sketch of what I wanted the complete artwork to look like and paid a commercial artist to do me a nice black and white cover. I then just had to color it myself, add the game screenshot, Tandy Color Computer logo and catalogue number and it was done. As with Donut Dilemma, I had the covers color printed to ensure a high quality.

With my sales momentum generated by Donut Dilemma, Rupert Rythym was snapped up by Tandy Australia. This time, without the support of a Christmas computer package, it sold 850 copies to Tandy Australia. Still a respectable number and I could still keep wearing my "I'm not a failure" t-shirt with pride.

Space Intruders Title Screen
Space Intruders Title Screen

Space Intruders (1988, Tandy Color Computer 3)

With Space Intruders, I decided to go retro. Up until now, all my games have been original concepts derived from elements from other games. This time I have taken the classic arcade game of Space Invaders (actually Space Invaders Part 2) and jazzed up the graphics.

There were many Space Invaders clones for the original Tandy Color Computer over the years but none that I felt were anywhere near as good as the original. There were certainly none written for the new Color Computer 3 and that is probably because Space Invaders was a dated idea. I hoped that by giving the graphics an update, it may give it a new lease of life. Plus, Space Invaders is a simpler game to create and this would give me an opportunity to try some new routines I had been designing for the new Color Computer 3.

Story pretext...

"Enemy alien creatures have been identified entering our solar system, their destination, our home planet! Their goal, the total annihilation of our race. They must not be allowed to land!
As you position yourself at the helm of a giant particle beam laser cannon, you sense that sinister rhythm of the Space Intruders as they break through the cloud cover. You immediately unleash the awesome power of your cannon destroying them one by one as they descend towards the planet surface.

Suddenly a report comes to you from control headquarters. A gigantic alien vessel has also entered the solar system. Could it be the Alien Superior?!

A bloated description that basically says, "Get the buggers before they get you!"

Space Intruders Comparison with Space Invaders
Comparing Space Intruders with Space Invaders
In designing the new graphics for Space Intruders, I wanted something that looked contemporary but still retained elements of the classic graphics used in the original arcade masterpiece. The new enhanced graphics still bare a strong similarity with the original.

Another reason I chose to do a less ambitious game was that I was exploring new ideas for graphics and sound engines. My old graphics engine created all the graphics "offline" in memory and then switched the displayed page to this offline image when a frame was complete. This time, I did everything on one screen. This was also due to the number of moving characters, 55 in all, that would have created a bigger slowdown than what I experienced in Rupert Rythym had I used my old techniques.

I also experimented for the first time with "interrupt driven routines." The idea was to set up the player's laser base object to be interrupt driven. The main program would only drive the alien invaders, sound and all missiles while a separate subroutine was called up at fixed intervals via a hardware interrupt that would move the player's laser base left and right. It worked very well, and the laser base moved silky smooth. I recall a few moments during development when the program would crash and everything on the screen would freeze or corrupt, yet the laser base continued to move smoothly left and right across the bottom of the screen. I liked this interrupt driven stuff and I had to find other ways of using it in the future!

Space Intruders Game Screen - Level 1
Space Intruders Game Screen - Level 1
Space Intruders Game Screen - Level 9
Space Intruders Game Screen - Level 9
I did add some extra innovation to the old game of Space Invaders. In the original, you can never win. You are presented with wave after wave of enemy invaders until you finally lose all your laser bases. In Space Intruders, there are eight waves of progressively harder rounds and in wave nine, the Mother Ship arrives! This part of the game is modelled on arcade Phoenix (sort of a return to my earlier game, Cosmic Ambush) and you are required to penetrate the base of the Mother Ship and eventually shoot the Alien Superior within before the vessel lands and invades Earth. Accomplishing this, you actually win the game!

Again, Tandy Australia marketed my game. Again I created a rough sketch of the artwork I wanted and a commercial artist created a final sketch. Tandy allocated a Catalogue Number and I arranged for tapes to be duplicated.

But I saw a disturbing trend. Tandy placed two orders, the first for 200 copies, the second for 100 copies... and that was it. 300 copies only. It was late 1988 and I was starting to suspect that the Color Computer was starting to run its round. There was still enthusiasm in the US, but here in Australia, it didn't seem so positive.

Understandably, Tandy was promoting their Tandy 1000 range of IBM compatible computers. Higher price tag, larger profit. But in Tandy's credit, they were one of the few manufacturers still selling an 8-bit computer while the rest of the market had moved on to 16-bit systems such as Commodore Amiga's, Atari ST's, Apple Macintosh's and IBM 286 PC's.

Space Intruders Packaging
Space Intruders Packaging
I decided that it was time to make inroads into the US market, and I found an opportunity via a new startup company called "Game Point Software." This was a company being run by a nice fellow by the name of Peter Ellison who was at the time selling some game software by the famous Color Computer games programmer, Steve Bjork. He was advertising for new games submissions to market, so I sent copies of my Donut Dilemma (Color Computer 3 version), Rupert Rythym and Space Intruders. He liked them and added them to his product line. He had new game packages made up and ran full page advertisements in The Rainbow, the largest Color Computer Magazine at the time. My games received positive reviews in various Color Computer magazines and sales were reasonable. I don't know the exact number of copies sold because we came to an arrangement of payment via a barter system. He maintained an account of the money collected, and I would request things like the purchase of some software or the subscription of certain magazines. I was happy with this arrangement because it made up for the blackout here in Australia of Color Computer products and information about what was going on in the Color Computer world. Sales were nothing like what I had achieved via Tandy Australia, but I felt that some sales were better than no sales.

Then, something strange happened. Game Point Software disappeared! It just closed up shop and vanished. It was very strange because I found Peter Ellison to be a very friendly, helpful and honest fellow, but something must have happened causing him to fold overnight. I never heard from him again. Oh well, that's how life is in the fast lane I guess... and there goes my US link.

Cosmic Ambush (1992, Tandy Color Computer 3)

After a short departure with a hardware project for the Tandy Color Computer 3 (a simple video digitizer) I returned to game programming. However, by 1992, The Color Computer market was not what it used to be. Here in Australia, the Color Computer had finally been discontinued. Access to the US Color Computer market was hard to come by with no easy access to Color Computer magazines for information. It seemed like a Color Computer blackout. I knew that my only chance lay in tackling the US market before the Color Computer was also discontinued there.
Cosmic Ambush Title Screen
Cosmic Ambush Title Screen

I therefore decided that my next game had to be impressive, it had to fit into a 32K ROM cartridge and I had to pitch it to the Tandy Corporation in the US. It was my last hope.

No Story Pretext!

I never actually created a storyline for Cosmic Ambush for reasons that you will understand as you read the rest of this page. The game was a vertical shoot-em-up which had you piloting a space craft (with a cool revolving gun barrel!) and defending various space fortresses from a variety of enemy attacks. Your space craft had a variety of weapons starting from a meek single shot gun up to multi-fire. Upgrading your weapons required you to hit the weapon upgrade targets that randomly appear, but a direct hit to your craft would downgrade your weapon as well as drain some of your shield energy. Various recharge targets are available for you to re-energize your shield. There were a variety of enemy craft each with its own unique combat style.

The major deciding factor for this game that determined how large the code could be, how much graphics and sound I could include and how the entire program is to be stored in memory was based on the goal that this game was to be marketed as a 32K ROM cartridge game. 32K was the largest size cartridge that could be used on the Color Computer 3 without resorting to additional circuitry within the cartridge. I had seen how many of the successful game sales were on cartridge and this was due to the decrease in software piracy by using a cartridge medium compared to a magnetic medium such as a floppy disk or cassette. With 32K as my limit, I wanted to create a game that appeared far bigger. I wanted lots of smooth scrolling graphics and sampled sound effects.

I had worked out a way of creating unlimited smooth vertically scrolling backgrounds. I had developed a new method for creating sprites. I also developed a new sound routine that used the Color Computer 3's programmable timer interrupt to provide two channel sound effects during the game with no noticeable interruption in graphic animation. I was planning on Cosmic Ambush to be the best "shoot-em-up" style game ever created for the Color Computer. But alas, trouble struck... big trouble.

Cosmic Ambush Game Screen
Cosmic Ambush Game Screen

Half way through developing the game, Tandy in the US officially discontinued the Color Computer. This meant that they were not stocking anything new for the machine. That was the final nail in the coffin for me, and I felt that Cosmic Ambush had no future... so I stopped development. I was quite disappointed, but I knew I couldn't blame Tandy. The time for 8-bit computers was well past the use-by date, but I guess I felt that the Color Computer 3 had not had its full potential tapped.

Six months went by when a friend of mine came over to my home and asked to see what I had done with Cosmic Ambush. I dug out the old files and loaded it up. I began demonstrating the game and my friend was very impressed with what he saw, but what caught me by surprise is how impressed I was! It's amazing how different things look when you haven't seen it for awhile.

I decided then and there that I was going to finish Cosmic Ambush, at least to a point of being complete enough to release as shareware. I thought that maybe shareware was a viable way of "selling" it. I had omitted various planned features in the game such as a scrolling starscape behind the scrolling background to create a parallax effect. I simplified the enemy flight patterns that were originally to be more like arcade Galaxian. And I didn't create any game instructions or package artwork.

Well, as shareware, Cosmic Ambush sold one copy at $7 US. That sent me a strong message... there was no future in game development for the Tandy Color Computer. I made Cosmic Ambush freeware and I packed up my Color Computer 3 and became an Amiga user.

I had owned an Amiga 1000 for a few years and was very impressed with it, but unfortunately, I never had time to do any actual programming on it. I had fallen behind with that machine and I knew it would take a long time for me to develop anything worthwhile that could compete with existing products.

It was the end of my Color Computer era.

Pac-Man Tribute (1997, Tandy Color Computer 3)

After leaving the Tandy Color Computer scene in 1992, I spent most of my computer time playing with Commodore Amiga's. I had an Amiga 1000 and then moved on to an Amiga 1200. I liked the Amiga's because they had, great hardware and an efficient, reliable and responsive OS, but I never programmed anything for them. When Commodore folded and the resurrection of the Amiga by another company was looking more like a myth, I jumped onto the PC bandwagon with a Celeron 300Mhz system. I hated Windows! It was the complete opposite of what the AmigaOS was except that it had a huge software base and was supported by so many companies with their products. It was clear that this was the future of home computing (over 90% market share!).
Pac-Man Tribute Title Screen
Pac-Man Tribute Title Screen

What was also clear to me was that the days of creating commercial software as a one man show operating from a bedroom were over. It was hard to make a dent in this market unless you joined up with a software company. I had also fallen far behind with current popular programming languages like "C" and was unfamiliar with game programming on the PC. Yep! I was an old dog that couldn't learn any new tricks!

So, I did what all "old dogs" do and that is search around for other "old dogs" to talk about the "good-old-days," and I found it in the form of the Color Computer newsgroup on the Internet.

I was surprised to see that there was still some life in the Color Computer. I discovered new programs that other Color Computer enthusiasts had written during my years of absence. I made some good friends and even caught up with some old legends from days gone past. I was starting to get the bug again, and I decided to create just one more game... just for the fun of it.

Story pretext, I'm not to blame for this one!

"You are PAC-MAN, a friendly-looking yellow circle with a little wedge missing. You travel through the maze, eating dots in your path and are pursued by four ravenous monsters. If any of them catch you, you're a goner.

There are four 'energizers', one in each corner of the maze. Hit the energizers and the monsters are rendered helpless and you can eat them, making them disappear for a few seconds.

If you eat all the dots on the board, you are rewarded with another board, in which the monsters have become smarter and stronger.

I think everyone knows this story and for those who don't... you missed a great era in the history of videogames!

I set myself an important design goal for this project. It had to look, sound and play as close to the original Namco classic as possible. I didn't want to do Namco the injustice of another poor clone and I wanted to do the Color Computer 3 justice by showing what could be achieved. The game had to run at 30 frames per second, the maximum frame rate of a standard TV or CM-8 RGB monitor (the monitor sold by Tandy specifically for that computer).

I should point out that at the time, I didn't have the MAME arcade emulator for PC or Macintosh. Instead, I recreated all the game graphics by redrawing them on my Amiga based on observing a real Pac-Man machine and what I could find in magazines. The sounds were sampled on the Color Computer off tape recordings made from a real Pac-Man machine.

Pac-Man Tribute Game Screen
Pac-Man Tribute Game Screen

I made improvements to my dual channel sound routines from Cosmic Ambush to the point where sound generation took up minimal CPU time. I improved on my sprite graphics routines to achieve more speed. I used the tallest vertical resolution I could muster on the Color Computer 3 of 320 x 225 pixels. I allowed the maze to take up this full height by moving the score displays to the left and right sides of the maze. This allowed me to create a screen aspect ratio that wasn't too far off from the original. I included all the animated interludes between mazes just as the original and also added the feature from the original where the Pac-Man moves slightly slower than the ghosts when eating dots, but gains a slight distance when it is taking corners. This is an important characteristic used by expert players of the original.

One area I could not work out from the original was the ghost character's intelligence algorithm so I had to develop my own. I spent some time trying to think up an algorithm that would give similar results to the original and this is what I came up with...

I created five "target" points on the screen positioned in the four corner areas and centre of the maze. Each of the four ghosts is given one of these targets points and they work their way to each of these. I set a timer on these target points and when the timer count reached zero, they would roll their positions into the next target point in the list. So, a target point pointing in the top left corner of the maze would shift to the bottom right after a time, then to the top right and so on. This kept each of the ghosts "patrolling" the maze without them bunching up together for too long.

As each ghost navigated the maze to reach its target point, it would check to see if the Pac-Man was on the same row or column position on the screen. If it was, the target point is altered instantly to point to the position of the Pac-Man. The ghost would then begin to close in on this point until the timer timeout reset the target point back to its normal cycle.

Pac-Man Tribute Packaging
Pac-Man Tribute Packaging

With this algorithm, the ghost movement is very similar to the original when viewed at a glance. I was happy with the results of the gameplay and that is how it stayed.

I kept my expectations low for sales of this game. There was no Tandy to sell through, no local clubs, no printed magazines (except CFDM, the disk magazine) and not a large user base. I had set a top end projection of 20 copies. To date I've sold 70, which is pretty good considering the conditions.

I sold almost all my copies to US customers. The local Australian Color Computer scene seemed non-existent. These sales gave me the confidence to continue with more Color Computer product development.

Gate Crasher (2000, Tandy Color Computer 3)

For a long time, it was being debated if the Color Computer 3 could create a true 3D game along the lines of the PC classics, Doom or Wolfenstein 3D. Many said that the Color Computer, as many of the early 8-bit machines, was too slow to do the necessary 3D calculations required to render each scene at a decent enough frame rate to make a fast paced action packed game.
Gate Crasher Title Screen
Gate Crasher Title Screen

But one man was able to provide a glimmer of hope on this subject, John Kowalski (). He had developed an algorithm that did the necessary calculations fast enough and created a demo program to prove it. The demo was called Gloom and in it, one could navigate around a 3D environment using a stock standard Tandy Color Computer and it ran at a good frame rate.

This impressed everyone, but there were many who felt that the final proof would be to create a full game. I decided to take up the challenge and Gate Crasher was the result. A Wolfenstein 3D style game featuring full 360 degree 3D environment, explosive two channel digital interrupt driven sound and five levels of the hottest action seen in a CoCo game for years! This game clearly proved that 3D gaming of this type is possible even on an old 2Mhz 8-bit computer.

Story pretext, this one is good!

"It is an era of high technology, an era of perfection, an era of the mind enhancing Brain Implant devices. Small microcontrollers implanted into the human skull acting as a "co-processor" to the brain. With this device, a persons abilities can be enhanced while disabilities removed. Millions of people worldwide have undergone surgery to have a device installed and reap the benefits of an improved lifestyle.

"He who controls the mind, controls the world."

But there is now evidence to prove that there is more to these devices than creating the perfect human. Leaked information has revealed that each implant has a means of remote control via the internet-providing low orbit satellite system also owned and operated by the same company creating these implants. This has been found to be used as a form of mind control allowing the CEO of the company to control things such as the outcome of an election, the buying habits of consumers, even to invoke death!

You are the Gate Crasher and it is time to crash this party, destroy all the computer data and defeat the evil CEO himself!

Gritty, prophetic and visionary all in one!

The biggest challenge for me in this game was making everything run at a decent frame rate. This was accomplished with the aid of John Kowalski's Gloom 3D environment algorithm as well as heavy use of self modifying code. Gate Crasher represents a milestone in Tandy Color Computer gaming in that it is the first true full 360 degree, free movement solid 3D action game of this type for this machine. The game uses an unofficial 128 x 96 x 16 color graphics mode. Even utilizing double buffering, each screen only takes up 6K of memory, reducing the workload on the CPU to update each display frame. A further optimized version of the dual channel interrupt driven sound routine used in my last game allowed explosive sound effects to be had without too much CPU overhead.

Yes this game had it all... the player's gun would bob up and down as he walked, you could hear your footsteps, your gun recoiled when it fired, security doors that could only be opened by cracking the color coded locks, the gun would make a cool reload sound when ammo was found and the evil CEO had a classic evil laugh!

Gate Crasher Game Screen 1
Gate Crasher Game Screen 1
Gate Crasher Game Screen 2
Gate Crasher Game Screen 2
The storyline setting for Gate Crasher is obviously futuristic. Set in the near future, the vision is of a world under the control of a powerful corporation head who has found a way to control the minds of the unsuspecting public by feeding them hope and an enhanced way of life in the form of a brain implant that he can secretly control.

In this game, you infiltrate the five level building of the corporation with the goal to destroy all information about these implants, but I have planted a little surprise on level five. Here you encounter the head CEO, the man responsible! He hides in his large office which is heavily surrounded by his "suits". Once you get past the suits, you get to fight the CEO himself... and the little bugger has a very familiar face. Look at the title of this game to get a clue.

A really cool feature is that when you destroy three or more suits in rapid succession, the computer lets out a "Woohoo!" to signify the adrenalin rush. Oh well, I have to do my part to promote violent behaviour in this modern world.

I was aiming at this game being released for the upcoming PennFest 2000, a Tandy Color Computer festival held in Pittsburgh, Pennsylvania, USA, that I was a co-organizer for. I knew the Color Computer market was getting smaller and smaller as time went on and I felt that most sales of this game would be had at that fest.
Gate Crasher Packaging
Gate Crasher Packaging

I was right. About 45 copies of the game have been sold to date, making it less than my last game, Pac-Man. Even though Gate Crasher represents a milestone for 3D action type games for an old 8-bit computer, the market has shrunk so much that I felt that my game programming days for this computer have come to a close. This was to be my last game for the Tandy Color Computer.

The End

Well, we've reached the conclusion of my story. I never did become a famous videogame programmer, but I don't feel that the last 25 years were a failure. I've had an incredible journey, learned many things, met many talented people, made many friends and shared my enjoyment of videogames with people around the world. I'm not rich but I have a stable job in the computer industry.

I hope my story has been an inspiration and a source of knowledge and awareness to others who may share a similar dream to mine.

Nickolas Marentes Signature

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bullet Bill Loguidice | 16 Nov : 00:03

Comments: 307

From an e-mail from the author, Nickolas Marentes:
"Mathew Reed, the fellow who has created the TRS32 emulator has sent me an e-mail telling me that the problem with the incorrect timing at the title pages of my Model 1 games is not a fault of the emulator but has discovered that the TRS-80 ROM images available off the net have been patched to remove a ROM call that contains a delay routine that my games called. He said that he is putting out a fix in his next revision of TRS32 that will compensate for this."

bullet ElmerA | 10 Feb : 02:19
Comments: 2

Registered: 10 Feb : 02:11
This article has really intrigued me and sparked an old interest to learn how DOS-based games are programmed. I just wanna know what current platform Nickolas or any of you readers would recommend if someone would take the same path he took. Granted, the days of bedroom game development are gone but still, if you could still do it, what would you use and would it be worth it in the end?

bullet Bill Loguidice | 10 Feb : 10:13

Comments: 307

Well DOS-based programming is really unecessary these days, particularly since many Windows systems don't have a true DOS mode and it will be difficult to support modern video and sound cards properly. With that said, there are tons of tools that work within and for the Windows environment.

What tools to use depends on a lot of factors, ElmerA, including your own programming background or lack thereof, and your inherent mathematical ability. There are basically two sets of tools you can use to create a fairly competitive "homebrew" game by yourself (though many of us like to tap people with artistic or musical ability to handle those aspects), though results obviously vary. There are the tools like "Multimedia Fusion" and "The Games Factory" (both from ClickTeam) that allow you to create games and other programs without any programming. You click and place visual elements to create programs. The downside is that there is often a performance hit, but if done properly you can produce nice results and make a saleable budget game. The second set of tools are those that are specifically focused on game programming and are basically optimized variants of BASIC. These include "Blitz Basic", "Blitz Max" and "Blitz 3D" (all were or are from Blitz Research). These can produce full speed commercial quality games, but you need to learn the languages and do actual coding (though it's MUCH easier than learning "C"). Somewhere in-between these two options are programs like "Game Maker" by Mark Overmars, which has a click and place visual option or you can actually get in and code. Regardless, all of these products are either mostly free or offer mostly functional trial versions, and the support communities are generally strong. You can read more about "Game Maker" by reading Mat T's article from our Issue 6 called "Computer Camp Catastrophes".

Of course there are those that will argue you're better off going straight to a "real" programming language like "C" or "Visual Basic" or something similar so have more real-world skills, but those require a significant learning investment and are beyond many people, including myself.

There is actually a very good and free online education service that can also teach you these languages. If you want more information about any of this, start a new topic in our forums and we'll expand this discussion.

Anyway, is it worth it? I say yes. Producing something with your own hands and talent is immensely rewarding, even if you give it away for free. Creation is among the highest satisfactions in life.

bullet Mark1970 | 10 Feb : 10:20

Comments: 114

There are a lot of active platforms where homebrew / bedroom game programming still is possible:

Developing for Sega Dreamcast is fairly easy, open source development tools are widely available and the console is able to boot from a cd-r without hardware modification. Provided the right open source tools are used to properly format a dc-compatible iso image.

Same thing goes for the open source Gp32 platform. Both platforms have lot of shared developing libraries and its fairly easy to create a piece of software that runs on both machines. Fenix is one example of these libraries.

bullet Bill Loguidice | 10 Feb : 15:17

Comments: 307

Well, those are fair points, Mark, but surely those options require a great deal more skill and knowledge over the straight Windows options I described above.

And just to add to what you mentioned, there are strong Atari development communities, particularly for the Atari 2600, which is the most active of the classic platforms in terms of new developments. Of course new hobby games are being made for a lot of classic systems, including ColecoVision, Vectrex and the systems you mentioned.

bullet ElmerA | 10 Feb : 19:28
Comments: 2

Registered: 10 Feb : 02:11
Thanks for the inputs. My desire to get back and learn DOS game programming has a lot to do with my current work as a mobile games developer. I was able to jump to Java (J2ME) game development for phones but I realized that (1) I still lacked knowledge on fundamental game programming techniques (collision detection, page flipping, etc.), and (2) I need to squeeze every ounce of performance over the target device and my code. I think since this was the discipline brought about in DOS game development (largely because of programmability and device constraints), I think looking back and probably seeing how it was done before would really help.

But taking Nickolas' path where he intended to sell games by his own -- I don't know -- perhaps the same path can be taken on with mobile games. You could probably sell your work at Handango or get operators to buy your game.

Ah, but there's the angle of programming for novelty. If there are people who are collecting old game machines for novelty, you might say I'm one of those who's interested in programming and coming up with NEW games for these OLD machines for the same reasons. I might look into that Atari 2600 development.

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