Tuesday, 22 November 2022

Cranking the handle for a while to come

Xevious is progressing well, although there's not a lot of exciting new development to blog about. I've been filling out object handlers with just enough code to display the object (if possible) and allow the map parsing and the game to continue. Still a handful of glitches but, as of now, it doesn't hit any unhandled objects or functionality until Area 7. Some of the Grobda (tanks) are even moving now!

Random screen shot - revealing Bonus Flag location

I've coded the pseudo random generator; it still requires more thorough testing but should generate the same sequence as the original. As a result, it no longer hangs at the bonus flag on real hardware. I also have a build option that reveals the bonus flag locations; it simply sets the sprite tile to the 'flag' rather than the invisible tile. I'll do something similar for the Sol Tower when I get to it.

The object handlers aren't finished, so some glitches
like one of the Derota colours above

Consequently, the SUB CPU code is almost complete now. Once the map can be completely parsed for all 16 areas, I'll look at finalising the code for it.

The plan moving forward is to complete a skeleton implementation of all the object handlers. Then it'll be a matter of going back and fleshing out the functionality for each object. A handful of the simpler ones (eg. Barra, stationary Grobda) are already complete. In order to test the full lifecycle of the objects though, I'll have to implement firing and bombing first, and I may as well implement scoring while I'm at it.

There should be steady, if not exactly spectacular, progress over the next few weeks. And of course holidays and family time will interrupt that at some point.

UPDATE: The game runs through all 16 areas on the map now, which means all ground-based object handlers at least have stubs. It also means the SUB CPU implementation is all-but-complete!

TRIVIA: Area 14 has NO ground-based objects!

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