Pacific Palisades, CA
Here's a game that's easy to program, short, and fun. There are versions of the game here for Atari, PET/CBM, Apple, and OSI.
"So what does your computer do?" I remember my parents asking me that question over and over again when I was a teenager, just getting into computers. I couldn't begin to answer a question like that. So, instead, I wrote a simple demo program to show them what was possible. After an hour of programming with my new O.S.I. Superboard II, I came up with Shooting Stars.
I originally saw a program like this on a friend's computer system and thought it would be easy to convert to my computer. And indeed it was.
The object of the game is to clear the screen of as many targets as possible using the fewest missiles. The number of targets is variable. When you first start the program it will clear the screen and print the welcome message. After a few seconds it will ask, "HOW MANY STARS?". Depending on how complex or how long a game you want to play, you can enter the number of targets you want to fire at. A suggested value is 30 to begin with. The program will then set up the star field and start the missile launcher.
To launch a missile, wait until the launcher passes under a star and hit the space bar. The number of missiles is unlimited. Your score is the ratio of missiles to targets destroyed. If you want to finish the game before you destroy all the missiles, press the A key. After you finish it will tell you how well you scored and ask if you want to play again. To play again leave another quarter under your computer and type, "Yes."
There are a number of areas where this program could be expanded. For example, add sound effects using the audio output port, make the number of missiles limited, or make the targets mobile. As the program is really very short when it has been condensed (using multiple instructions per line) it shouldn't take you a long time to add to Shooting Stars.
It's not a very complex program, but it does impress "non-computer" people. And it answers the question, "So, what does your computer do?" Well, at least for a while.
Note: If you added Super-Cursor (COMPUTE! December, 1981, #19) to your Superboard II, then the clear screen subroutine at 1000 is unnecessary. You can replace it with: PRINT CHR$ (1), CHR$(2). This works only with Supercursor.
This is not a line-by-line translation of Mr. Cohen's Shooting Stars program but rather, a game programmed especially for the Atari which plays a similar game.
The object of the game is to destroy a number of shooting stars (you select how many). Your score is the percentage of stars hit versus shots fired. Press SPACE to fire.
The game is fully commented, so you can trace the execution of the program and modify it as you please. Note that this game uses a little-known Atari graphics mode. More applications of these four color text/graphics modes would be welcome.