I decided to create a 'random walk' in an attempt to create something that would look like an abstract map of a city. I am quite pleased with the results.
Pictures first, and then the code.
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| It's supposed to look sort of 3D, sort of. |
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| It really pelts along on my Raspberry Pi |
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| When the line wanders off the screen it starts again in the middle of the pattern with a slight offset and a new colour. Lines sometimes quit and start again (controlled by the variable LIMIT%, and after a while the pattern will refresh (controlled by the DENSITY% variable). |
Here is the source code for RISCOS BASIC V, which will require only minor modification to run in BBC BASIC for Windows, or on a BBC Master.
Copy the code below, or download the file directly.
10 REM Draws a 'city scape'
20 REM T Street
30 REM 2017-05-10
40 MODE 19
50 ONERROR IF ERR=17 OSCLI("*DESKTOP")
60 colCycle%= 0
70 GCOLRND(4)+colCycle%
80 REPEAT
90 refresh%=FALSE
99 REM Origin
100 xo = 500 :yo = 500
109 REM start at origin
110 x = xo :y = yo
119 REM distance moved each step
120 dx=0:dy=0
130 m = 16
139 REM counts number of steps
140 c = 0
150 l=0
160 LIMIT% = 400
170 DENSITY% = 32
180 MOVE x,y
190 REPEAT
200 c=c+1:l=l+1
210 x=x+dx
220 y=y+dy
230 DRAW x,y
240 r = RND(4)
250 IF r=1 dx = 0:dy=m
260 IF r=2 dx = m:dy=0
270 IF r=3 dx = 0:dy=-m
280 IF r=4 dx = -m:dy=0
290 IF x<0 OR x>1000 OR y<0 OR y>1000 OR c>LIMIT% THEN
300 xo = xo+2:yo=yo+2
310 x=xo
320 y=yo
330 c=0
340 MOVE x,y
350 GCOLRND(4)+colCycle%
360 ENDIF
370 IF l>LIMIT%*DENSITY% THEN
380 refresh% = TRUE
390 ENDIF
400 UNTIL refresh%
410 colCycle% = colCycle% + 4: IF colCycle% > 128: colCycle% = 0
420 CLS
430 UNTIL FALSE