Slaughter

Item scaling is harshly limited by hardware. I might add more steps for getting smaller with distance, but they simply cannot scale up, because of the sprite budget. That's why they circle in midair. The circle scales very well. If you see a tight little orbit, run to it.

Dropoff edges have distinct tiles, where any flat space ends. They're not pretty but they're there. The larger hurdle for platforming is that you can't look down. But if you're holding A, the fall speed is low enough that you can walk off a platform, and then back up back onto it.

The buzz has been fixed! Badly. The sound hardware needs 17 bytes somewhere in 0xC000, and it needs them aligned on 64. If cc65 has a sane way to place data at a specific address, then anybody who knows is keeping it a secret. Some function that happens to be in-range has to smuggle in eighty-one zeroes in a row... as instructions. Constant data is separated. So there's eighty-one BRK instructions, 0x00. Which I then manually locate in the output ROM, to change which address I write to the audio chip.

Some parts of this project feel ingenious. Other parts are dumb as hell.

Sorry about the buzzing. The HUD is kept stable by abusing the sample channel, which can only read from a particular region in the middle of ROM, and placing things there specifically is nontrivial. I had thought it was pretty quiet, but these headphones might not be very good. I'll somehow point it at all-zeroes in future ROMs. 

The HUD has to use the background now (where previously it was solid gray that scrolled freely) so I could afford to show three ammo counters. I tried using two sprites as the endpoints of their shared gauge, but the budget per-line is eight, so no. Fortunately I was hopelessly stubborn about the sample-channel thing. The NES's audio chip is on a separate clock that only kinda lines up. Using it for timing is rough. But I got it to fire an interrupt anywhere within the first dozen lines of the HUD, which was enough to leave the top part boring and fancy up the bottom. Aaand then I got the range down to within two lines. I'm still not sure how. It has to play a noise to do this, and I will make that noise a period of silence.

Multiplayer currently has friendly fire disabled, purely because I made hitscan independent of rendering, and have not bothered to check for the other player. Multiplayer also has some head-scratching bugs whenever it goes back to singleplayer. I had to push this update with several cans still freshly-kicked.

This update is mostly behind-the-scenes. I spent a few months tweaking performance as hard as possible, to where everything's about twice as fast as the last version. That let me update sprites on every frame and move fireballs more often. The levels are nearly the same, albeit with the new palette stuff, which is smaller and faster. Floor / wall graphics are more flexible, so there's now more than four types, but several of them are still fugly. The sound effects are different, mostly picked from randomly-generated examples. I was having no luck reasoning about the NES's sound chip. I made it cheap to throw a byte into a function and get out some kind of sqwonk or breep. I've picked good ones for everything that should make noise and a few things that are funny when they make noise. 

This was supposed to head toward a NESdev 2024 release. But I guess that's cancelled? Even the Discord look ambiguous. In any case this was all cleanup and prep to have it Done™ somewhere in November. That should still happen. I'm gonna keep freeing up space so I can cram in more levels. Make it feel more like a complete game. That's definitely something the ammo has already changed. The enemy pinatas finally matter!

You'd need cc65 installed. I'm using v2.18, but the newer versions should work the same. In Windows you might as well install Windows Subsystem For Linux and use "make". But if you wanted to do it manually, or create a batch file, there's only four commands in the makefile. They're in reverse order. cc65 goes from slaughter.c to slaughter.s, ca65 goes from slaughter.s to slaughter.o, ca65 goes from reset.s to reset.o, and ld65 combines the .o files into slaughter.nes.

... I forgot to include a ROM in the update, didn't I. Lemme fix that real quick.

Ha ha, yeah, splitscreen multiplayer would be ridiculous.

So anyway the splitscreen multiplayer is jump-in co-op with friendly fire. Press Start on controller 2. 

Originally this response was going to be within a day of your comment, because this project is so ass-backwards, I figured it would take about three hours to implement side-by-side splitscreen. I was wrong. It took five. Literally one night is all I needed to have two independent viewports, because all column-pairs are independently raycast. Even the FOV is maintained... so I guess this NES game is set for anamorphic 16:9. What I've been doing for the last two weeks, instead of delivering that 'ha ha so anyway' punchline, is finding ways the game breaks if it tries counting to two. If you picture Sideshow Bob in that field of rakes, it's basically that, with more swearing.

I spent an entire day reverse-engineering my own view-weapon code so that removing bits from a byte would make bullets disappear when they hit something. Rendering the other player took literally fifteen minutes. There's a reason all programmers are Like That. 

Though if you're playing on PC you'll probably want Mesen to add scanlines after NMI. Single-player performance has been significantly improved. Splitscreen performance needs work. 

NES games tend to have tiles in ROM, so for better or for worse, combining tiles isn't a speed issue, because it's not an option. The character bank in this release honestly has abundant free space. I just haven't committed to diagonals, or marching squares, or approximate 2x2 mini-tiles or whatever. Consoles like this deserve one and handhelds would absolutely require one. 

Incidentally the Sega Master System would be fantastic for this. Flippable 16-color tiles, horizontal blanking interrupts, much more RAM. Expect cleaner and faster C code when the judging is over.