Workprint – May 2019

Last time I talked about the new, C64-specific version of C64CD blaster Stercore and this month continues that “trend”. It’s now officially called Stercore XD and I’ve actually got the majority of it written and working somehow!

Memory is getting very tight but all of the graphics are done now including some sprite animations – one of the aliens and the explosion have been “inherited” from Super Hyperzap – and everything just about fits into the lower half of the C64’s RAM after decrunching until the code grabs around 10K more whilst unrolling the background scroller. Spacial awareness is important here because I’m planning to put the final release version of Stercore XD out as a cartridge image for the RGCD competition. To that end the build process automagically makes a working CRT image for testing.

I still have a “to do” list including tweaks to the collision detection, a rewrite of the enemy movement code to optimise it, adding explosions and bolting in the simple attack wave driver from Super Hyperzap with a couple of small tweaks but, since there’s currently only about 280 bytes of ROM left in the 16K block the game has to occupy as a cartridge, some concessions might be necessary. To give a sense of scale, this paragraph is 457 bytes…