C64 Blood Money

Summary

While I still remember the details, I thought I’d go over my port of Blood Money to the C64. It had some really cool bits in it, and I had great fun doing it. Some parts make me cringe a little now, so it’d be interesting to revive it, and see if I can get it building again – or at the very least, go over the code again… One thing that DID bug me, even back then, was the crappy starfield. It was just some characters stuck in the map, and it sucked. So what were the main components? Multi-Directional scrolling Sprite Multiplexor Scripting Sprite compression Turrets Character sprites Bullets / Weapons Collision Shop Front End These are the major parts and we’ll take them one at a time. Before that, I want to briefly look over the code, and talk about the devkit – PDS. Programmers Development System. This was a lovely system, and one I’m sad I didn’t find while raiding the DMA Offices. The PDS system consisted of a PC ISA card, and a C64 cartridge. The ISA card was common for all systems, while the target cartridge was custom for each platform. As I can’t find a C64 image, here’s the Sam Coupé (Z80) one to show what it might look like.EDIT: So with the RMC Cave opening up a “Dev Den“, Jason who is running that part, had a C64 one and it turns out there isn’t an interface, just a user port connector. This makes sense as the C64 already has everything it needs to read/write bytes in parallel. This is the Z80 program, but the 6502 one was the same. It consisted of a built in text editor/assembler/debugger. The text editor could hold 8 files up to a maximum of 32k each, though you could include as many files as you like. It assembled before your finger left the key, and squired down in under a second. This was a massive speed boost from the 20 minutes I sometimes spent waiting on the C64 to disk assemble using a fast parallel disk interface. The other good thing about PDS, is it remembers the start date, and the last time you touched it – which is very cool and handy. So I...