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'''JD:''' The problem with using the high-resolution graphics mode is not only being unfamiliar with it, but also understanding the constraints. First, it uses up so much of the VDP RAM that there's only 2,000 bytes of RAM free for the programmer to use. Also, at the time, we felt we could not use sprite automotion in this mode. The problem we had was that the scroll used up so much processor time that in order for me to move sprites on the screen, I had to use automotion. If I were to move the sprites pixel by pixel as I did in [[Munch Man]] and [[Car Wars]], it would be way too slow. I had to go to automotion or else the project would have been killed.
At this point, Paul remembered that the 99/4A's newer architecture would allow us to do our own interrupt processing; this meant that we could do our own sprite automotion it if we relocated the sprite attribute table from where it normally was to the unused area of high-VDP RAM that I mentioned earlier. '''GMK:''' Where did the idea for the tumbling asteroids come from? '''JD:''' Paul Urbanus actually developed the different patterns in LOGO to get the tumbling effect. It was very easy to see the animation, and change the shapes accordingly. Then, it was a simple thing for me to just load the data for the different shaped into my program, change the coincidence a little bit, and away it went. . . '''GMK:''' It appears that the speech doesn't slow down the play of the game at all. . .it comes through as being a simultaneous process. How did you achieve this breakthrough? '''JD:''' Well, because we were already using our own interrupt processing for the sprite automotion, it made sense to also try interrupt-driven speech. This worked out extremely well; there was apparently no slow-down at all - even though there was 200 bytes of logic in the speech interrupt routines that had to be processed 60 times in a second. '''GMK:''' How did speech fit into the overall game design? '''JD:''' The idea behind the speech was to have a female onboard computer warning you of things that are coming - like when fuel is low and a fueling tunnel is up ahead, or that there's an attack on its way. So speech can be important in that it gives you some signals of what's coming up so you don't have to read the written messages at the bottom of the screen. You can still play the game without the speech; it was important, however, to make sure that speech wasn't totally integral to playing the game, because if someone doesn't have a Speech Synthesizer they would be out of luck. '''GMK:''' What were the reasons for simulating a female voice? '''JD:''' We wanted something different from the basic Speech Syntheiszer's voice, and also we were intrigued by the TV shows and movies that used a female voice as a spaceship's onboard computer. It seems to have a sort of mystical effect. Also, somebody told us that you couldn't digitize female speech because of things like high-frequency patterns. So, we just had to go off and do it. . . '''GMK:''' What are some of the obstacles in producing games for the Home Computer at this point in time? '''JD:''' The limitation is that you are working with an under-$200 computer with certain hardware architecture limitations that are built in. The only way to possibly overcome some of them is with software tricks. It's hard to create the tension and excitement of some of the commercial coin-op $3,900 arcade games - hard to compete with their special screens designed for each specific game, and hard to compete with their fancy remote controls. '''GMK:''' Do you feel that with [[Parsec]] you've just scratched the surface in what this machine can do, or have you already pushed the machine to its limits? '''JD:''' Well no - I think with[[Parsec]] it was just the beginning. With other games, I was becoming familiar with what I could do; but with [[Parsec]], I'm now getting a feel for what the machine can do. It's a kinds o launching and testing of some of the good points of the machine, and taking advantage of some of the speed of 9900 code. There are many other things that are really still out there that we would like to explore and exercise.
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