Machine Code Sprites and Graphics for the ZX Spectrum

Your Spectrum

Tony Samuels

Author John Durst tells us right from the start that the object of the exercise is to discuss the Spectrum display, machine code techniques and animated sprites; nothing covered in this book calls for the addition of peripherals. Chapter one goes into all the things you'll need to know to help you program well in machine code on the Spectrum. ROM routines have an important part to play in machine code programming and Durst explains the Save routine thoroughly, detailing how the header information is stored and how to play various tricks with it. In fact, as you can tell from the title, graphics play an important part in Durst's book. He talks about the character set and provides us with various routines to make it appear twice, four and even eight times its normal size, and others to make it bold, extra tall and extra wide. There are still more routines which turn characters on either side or upside down! Soon, we're getting very in-depth about sprites and animation. The first four sprite routines are none too impressive, but they do get better. The author talks of the Matte process - which does get a little confusing - but despite all that, at the end of it you're left with a pretty good sprite system. Here, and not a moment too soon, Durst adds some colour to the subject in the form of a number of attribute handling routines. The last few chapters give details on interrupt routines and what can be done with them, plus a tutorial on how to produce sound effects. They also set out to explain how to write efficient machine code. For £6.95, this is one of the best attempts at the subject I've seen so far.

Read it at Your Spectrum Unofficial Archive