Genre: Arcade      Creation Date: October 1984      Language: 6809 Assembly   Language    System: Tandy Color Computer 1 and 2


I finally decided that it was time to leave the TRS-80 Model 1 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, the Spectravideo and Sega machines and I was impressed but something inside of me said no. As time now has shown, my "gut feeling" proved right and MSX didn't catch on very well outside of Japan.

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 Color Computer. The Color Computer lasted till 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!

Original Story Pretext

"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.

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!"

Phew! I thought I'd never end!   :)

Game Development

The Tandy Color Computer was quite limited in its graphic capabilities. In it's highest graphic resolution of 256 x 192 pixels it could only display 2 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 4 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 that 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 black and white high resolution mode. The technique relied on the 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 8 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 used this mode and designed the graphics to make best use of this limitation.

Sound was another area I wanted to improve on over other games available for the TRS-80 Color Computer at the time. The Color Computer generated sound by the same method as the TRS-80 Model 1 by toggling a voltage via CPU intervention on/off to create sound waves. But it was a bit more advanced in that it could vary that voltage in up to 64 steps instead of the 2 (on & off) that the Model 1 had. In other words, it had 6 bits available instead of 2 for sound generation. I could actually make a sound fade off and create effects with more realistic sounds.

Unlike many of the other color 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. This ate into the time required for graphics but this was a challenge that I had largely overcome in the TRS-80 Model 1 and I included the same techniques on the Color Computer but using it's 6 bit capability. Neutroid 2  had colorful graphics and better sound than most of the Color Computer games at the time.

I felt that this game couldn't fail and I began dreaming of that luxury Porsche in my garage...

Marketing and Sales

Well guess what..... it was a flop!

I got daring with Neutroid 2, taking out a half page ad in an Australian Color Computer Journal. Nothing came of it, no sales. The only sales I made were achieved by demo's 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 means. 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!