Starfield on the Apple IIe

The term "scroll art" is new but these text-based programs don't require modern computers. Here is a video of the Starfield program (ported to Applesoft BASIC) running on a 1983 Apple IIe. This is the benefit of scroll art for learning to code: the concepts are simple enough that they can be applied to any programming language and any computer, even those from nearly a half-century ago!

The computer is an Apple IIe, though the monitor connected to it is from a Commodore 64 at the Recurse Center. The source code for the program appears at the beginning after the LIST command is run. This program is running at full speed with no inserted delays! The diagonal color stripe is not a part of the program; it's a "rolling bar" artifact of the CRT display and flickering that you don't see with the naked eye but appears when you record the CRT screen.

Joshua Bell has written an Applesoft BASIC emulator online that you can try out in your browser without installing anything.

Here is the BASIC source code:

5 HOME
10 CHANGE = 0.05
20 DENSITY = 0
30 WIDTH = 39
40 IF DENSITY < 0 OR DENSITY > 1 THEN CHANGE = -CHANGE
50 DENSITY = DENSITY + CHANGE
60 ROW$ = ""
70 FOR I = 1 TO WIDTH
80 IF RND(1) < DENSITY THEN GOTO 92
90 ROW$ = ROW$ + " "
91 GOTO 100
92 ROW$ = ROW$ + "*"
100 NEXT I
110 PRINT ROW$
120 GOTO 40