‘Arcade’ – Sinclair Spectrum White Lightning Feature – Part 3

This is the third (and final) part in a series of Spectrum White Lightning articles originally written in the late 1980s (when I was a teenager) for inclusion in our ZX Spectrum fanzine, ‘Arcade’. Having re-read my scribblings almost 30 years later, I don’t pretend to understand any of it. It might be useful. It might not. If you do find it useful or, at least, interesting, please leave a comment below.

From the user manual:

“White Lightning is a high level development system for the Spectrum 48K. It is aimed primarily at the user who has commercial games writing in mind and has the patience to learn a sizeable new language. It is not a games designer and stunning results probably won’t be produced overnight, but it does have the power and flexibility to produce software of a commercial standard (with a little perseverance!). “

Read part one and part two.

For some further context for these articles, please see ‘Arcade’ – A Sinclair ZX Spectrum Fanzine.

White Lightning Feature

Last month we had a program that scrolled a landscape left and right. This month we have a window scrolling in eight possible directions under keyboard control. (Phew! Advanced stuff, eh?)

Type the following proggy into screen 6:

0: SET 0 COL! 10 ROW! 20 LEN! 5 HGT;
1: UP 1 NPX! WCRV;
2: DOWN -1 NPX! WCRV;
3: LEFT WRL4V; : RIGHT WRR4V;
4: KEYS 7 1 KB IF LEFT ENDIF 8 1 KB IF DOWN ENDIF;
5: KEY2 1 1 KB IF LEFT ENDIF 1 2 KB IF RIGHT ENDIF;
6: TEST SET BEGIN KEYS KEY2 8 2 KB UNTIL;

That’s all it is. Imagine trying to do that in BASIC.

ENTER and SPACE for left and right. CAPS SHIFT and Z for up and down. SYMBOL SHIFT exits.

If you want to use your own keys, then here are the keyboard numbers (what a service!)

Notes on conversion:

Line 0: sets up the dimensions and positions of the window.

Line 1: defines UP. NPX is the number of pixels and WCRV is scrolling the window vertically with wrap.

Line 2: defines DOWN. As UP but -1 NPX indicates a downward scroll.

Line 3: defines LEFT and RIGHT. WRL4V and WRR4V are commands to scroll the window left and right by 4 pixels with wrap.

Lines 4 and 5: polls the keyboard.

Line 6: executes the program until SYMBOL SHIFT is pressed.

Next month: Who knows, I certainly don’t. Something good as usual.

Matthew F.

The Originals