RISC World


Lawrence Granville with more reader and editorial submissions

Well this month in StarProg we have four examples for you.

CFSSpeed by iSV Products

Do you use the Computer Concepts CFS filing system? If you do then you may well have discovered that opening a CFS filer window with a few applications in can be a lot slower than opening a normal filer window. This is because the !Boot and !Sprites files for the applications are compressed. CFS has to de-compress them before the computer can boot the application and load the relevant icon sprite. This little program solves the problem. If you drop a CFS directory on it it will scan it and de-compress all the small !Boot and !Sprites files so that filer windows will open quickly as CFS does not have to de-compres them. All other files are left in their compressed state. CFSSpeed is one of those little internal utilities that gets written but not really finished, however it does work really quite well!


Magic by G.A. Kattau

If you an still remember your school days then you may well remember the magic square from maths lessons. Well thanks to G.A. Kattau now you can make your own magic squares in a fraction of a second. The inspiration behind this program came from the book Mathematical Recreations by Maurice Kraitchik.

Magic Squares

Mazers by Joyce Haslam

Ditto the Dot is standing just inside the entrance of the maze, ready for the adventure of its young life. Guide it through the maze and out the other door.

In Mazer01 you can see the entire maze, but in Mazer02 and Mazer03 you can only see the squares Ditto has visited. Mazer01 and Mazer02 are on a single level, but in Mazer03 there are three levels joined by ramps up (white triangles) and down (red triangles).

The movement keys (left, right, up, down, jump) are defined in the first few lines of the program (as left$, right$, up$, down$,left1$, right1$, up1$, down1$, and jump$, jump1$). The first four (and jump$ in MAZER03) can be redefined in the game each time the program is run, while the others are kept as defaults. They can all of course be redefined in an editor. DON'T USE CHR$13 for any movement key other than JUMP!

These three maze programs were first written for the Atom and rewritten for the BBC. Here they are for RO3 and above. (They might work on RO2; I have no way to check.) Have fun playing and reprogramming them.


Wobble by Aaron

Here is this months offering from our editors vaults. Wobble takes a sprite and wobbles it. The original version worked in Mode 1, although I have no idea why. This new version uses Mode 28 for a hi-res wobble effect. The source code is quite easy to follow and you should be able to see how the effect works. However if you can't it really is quite simple. The main sprite is sliced up into small sections. Each section is then drawn at a particular height based upon a pre-calculated Cosine table. Why not have a try at altering the amount of wobble? And can you also see the cunning use of VDU28 text rectangles to mask parts of the screen?


What we want

That is it for this issue. I am still waiting for someone to use the graphics library supplied inside the !WarpSpeed demo from issue 4. Why not try and make your own demo using these general purpose routines. If you want StarPROG to continue then please do send in your contributions, remember no contributions means no StarProg!

Lawrence Granville