One of the demos I’ve carried across nearly all the platforms I’ve worked on is the rotating cube demo, typically with back-face culling (hidden line/face removal), perspective, and fast integer maths. The code has been ported to the Gameboy, CPC, PC, Atari ST and Scratch. On more capable systems I usually add filled-in polygons with simple texture mapping and Gouraud shading I first wrote this demo around 30-odd years ago for the Spectrum, and I …
I’ve been using the ZXSpin emulator for a while now to develop code on the ZX Spectrum. This has many advantages, namely an integrated assembler and disassembler, but quite a few quirks, and the editor, whilst adequate for small projects, is not really up to scratch for large ones. In addition, my main machine is an old Macbook, so have to boot into Windows on it to do any software development. My criteria for the …
I’ve been writing a smooth scroll routine for the ZX Spectrum over the last few days, based upon my recollection of conversations I’d had with Mike Follin at Software Creations whilst he was developing LED Storm and Ghouls ‘n Ghosts. The code is written purely in Z80 assembler and demonstrates the following techniques: Using the stack as a quick way to read and write blocks of data Using the vertical blank interrupt to run a …
