Police Car Demo
The original program is called CAR.BAS, which is a BASIC stub file (a file with BASIC followed by MC routines), back when I made it, I was using the Spriting Back Utility which was on the AA106 Covertape, which had it's own Sprite Designer. The idea with it was to draw a rectangle around the sprite and set it to 0 or whatever the background colour was, so it would wipe the Sprite as it moved. Apart from that the routine has it's own guide to how to set coordinates across the screen, I must of known how it work back then because it's quite different to Sean McManus' ESD Advance for example. The other feature of this demo is the Screen I made back then, I probably made it with the early GPaint from the AA80 covertape and then I used the early version of Colombia to compress the screen, which is what you can see in operation onscreen when CAR.BAS is initially RUNning.
Updated BASIC Version
It's still using the Spriting Back Utility from the AA Covertape, though I decided to use BASIC to draw the screen, the hardest part is the nature strip, I had to come up with a simple way of checking both sides of the curve and use MOVE and DRAW to fill those two points in, thus creating a simple FILL routine, I wasn't sure how good it would be, so I straightened out the angled edges, which left me with a bit of line to draw at the end, though generally speaking the general idea is there even if the median strip is slightly different. For the red dots to be placed in the centre of the Grassy area, it was simply a matter of working out Random Values between the 2 Points again, though use some conditioning when the Median Strip changed so it would remain within. Overall, I was happy with the result. The resulting program is called PATROL.BAS
Coding in Hisoft Pascal
From the BASIC version, I was able to come up with a Pascal equivalent, though I've been using Sean McManus' Easi-Sprite Driver Advanced, so I had to convert the sprite so it had dimensions and also changed the sprite to XOR, which means a Border isn't necessary. Since it's only a single Sprite, I also used Hisoft Pascal to build the Graphic up in sets, so the whole program handles everything from within. The most noticeable change between this and the BASIC version is obviously going to be the FILL routine, from the compiled environment it looks similar to the BASIC 1.1 FILL. The resulting Compiled Program being in PATROL.BIN
Police Cars aren't White!
Well maybe not now, but back in the 90s they were, well I suppose some still are here in Australia, a Highway Patrol car perhaps isn't, this looks more like your little Suburban Car doing it's rounds! :D