TobuNES

[sburrow]

Hey everyone!

Unveiling my latest project: TobuNES, a port/clone of Tobu Tobu Girl for the NES. See links below to original game:

https://tangramgames.itch.io/tobu-tobu-girl-deluxe

https://github.com/SimonLarsen/tobutobugirl-dx

Tobu Tobu Girl is a vertically scrolling platforming game where you bounce on bats, birds, and aliens to get higher into the sky and reach your kitty that floated away on a balloon. It's a very simple game, but is very skill based requiring quick reflexes. It is fun, and addicting.

What you see here is a prototype I made over the past 3 days (art assets from original game). It has all of the main game mechanics present: gravity, bounce, fly, dash, stomp, and scrolling. Just like the original game, I would really like to see some graphics and audio polish on this one, so expect more to come soon. This is all programmed in 6502 assembly for the NES. I have been referencing NesDev.org a LOT recently for ppu registers, oam bytes, and nametable addresses. Creating my own NES emulator was helpful to get me to learn a few things, but coding a game for the NES is a whole different experience. See attached code, it is partially commented!

I am using my PICnes emulator, as well as Mesen, for testing purposes. The GIF was taken from my PIC32MZ project running an earlier version of PICnes.

https://github.com/stevenchadburrow/PICnes

https://github.com/stevenchadburrow/AcolyteHandheld

If you want to play the game in your favorite NES emulator, change the TOBUNES.S file to TOBUNES.NES

I haven't created a GitHub repo for it yet. I want to fully change the art assets before doing that.

Thank you everyone! More fun in 6502-land!

Chad

[sburrow]

Updates!

Been working on TobuNES whenever I can between job, kids, church, sleep, etc. I feel like I've made a lot of progress! See attached GIF and (somewhat commented) code.

The main additions are various enemies, behaviors, effects, and animations, and some little things that make it look way more professional like the cloud poof. Of course I'm constantly referencing the original game to see what it looks like and how it should feel. I feel like I will have to make some adjustments simply because this is a much larger screen to work with, and whatever other limitations the NES has. I think that a vertical HUD and vertical parallax scrolling is nearly impossible unless I do some tilemap tricks or something. We'll see.

Next up is adding the warp at the end of the level, the level's progress bar, and a major overhaul of the background tiles. Eventually also the scoring system, and then level select. I have to focus on sound effects and music at some point too, but I'm kind of iffy on that because I cannot easily convert Gameboy audio into NES audio, I think? Foreign territory there.

Thanks everyone!

Chad

[sburrow]

It's amazing what a little bit of artwork can do to a project like this!

Been doing crazy math on how to get a seamless background that looks decent. See attached for screenshot and the pattern table. At this point I can take any 32x32 block and make it either the background or foreground. This will allow me to make all types of different levels. What you see here is the 'underwater' level.

I'm very dissatisfied with the bars on the side, I will definitely be redoing those soon. Also, although I got an 'end of level' trigger, it also needs a lot of work.

Progress! Thanks everyone

Chad

[sburrow]

Wow, a little bit a palette changes makes things really pop! See attached.

Rename the TOBUNES.S to TOBUNES.NES in order to play in your emulator.

This morning I was fixing a few issues, added a warp portal at the end of the level, and then making generalized level data in ROM. I can now make multiple types of levels, each with their own color palettes, enemy randomizations, map lengths, etc.

Still have those horrible bars on the right side! I just haven't figured out how to better deal with those yet. And I need to make a level select menu, scoring, etc.

Fun fact, the PRG ROM code for this game fits in under 4KB at this point, wow! My real crunch later will be the CHR ROM though. I'm targeting the NROM mapper so that it's super easy to use by any emulator, or fun to use for emulator development purposes. I believe Micro Mages, https://morphcatgames.itch.io/micromages, went this way, somewhat for the purposes of, "Hey, use this game to test out the emulator you are making!"

There you have it! I suppose this has become sort of a development blog at this point. *shrug* Thanks everyone

Chad

[sburrow]

Howdy again to whomever is reading

I finally got rid of those ugly bars, and replaced them with much better equivalents. It used up I think 4 extra 8x8 sprites total? So overall it really was worth it to change. See attached GIF, and the mostly commented code!

At this point I would say that the regular gameplay is basically 100% done. If there are adjustments to be made, then I'll do that as I need.

Next up is a level select, or something like it. A title screen would be neat, but hopefully not using up too much CHR ROM space. I also need scoring for sure, as that was a big part of the original game. I'd like to see what I can do with a tiny intro animation or something.

And of course, the music. That's going to come last, as I have zero experience with that anyways. Thankfully I have 28KB of PRG ROM left, so that should be enough for music

Thank you everyone

Chad

[6502inside]

It's nice work so far.

[sburrow]

6502inside wrote:

It's nice work so far.

Thank you!

It's final's week here, and it is VERY busy for me. If I'm not at work, I'm on the road back and forth! Tomorrow is a big grading day, and the next day is graduation, then Saturday is more grading... *sigh* So it is for a professor I suppose

Anyways! I have been able to code a little bit between this and that. See attached picture. I made a title page a while ago, and I've just been slowly adding more to it. I don't have enough CHR-ROM to put a full title, so I made one out of small pieces. I also added text pretty easily. The odd alpha-numerics on the side is the high score for the level, of which I will have four per level eventually. It's in hexadecimal for now, but you get the idea. The character (code named 'Tobu') is the select cursor, and the flying kitty in the background is part of the story. Today I changed the palettes and it looks a lot better.

So I need to fix the high score still. I also want to add some little clouds or stars or something for the background, maybe even animated. I also have been playing with 'effects' for the backgrounds of the main game. I'm imagining water or fire moving in the background by just switching color palettes, etc. The problem is that I don't want it distracting, so we'll see.

Then I need to change the sprites out with my own, and maybe make a little 'intro' scene. And of course audio still, but that's last.

Piece by piece, even during the busiest week of my year!

Thanks everyone.

Chad

[sburrow]

Hello everyone!

Almost done with Finals Week! In between I've been programming. See attached!

If you want to play the game, you must rename TOBUNES.S to TOBUNES.NES

The 'high score' is working now. Rather, it is 'previous scores' but that's fine for now. The decimals work now. That percentage algorithm was neat! Was thinking of posting about it on a separate topic

I also added lots of little things. The sparkles on the menu screen, only progressing to next level after completing the first, showing a floating kitty on the last level, etc. I do need to change those hideous backgrounds. Some levels are better than others. I also need to change a tiny bit of the math on the main game.

Lastly I want to make an intro scene, maybe still-frame with some text, not sure yet. Just the tiniest amount of backstory essentially: Your kitty floated away, go get your kitty, the end.

And then audio

Hope you like it! Thanks for reading.

Chad

EDIT: Small glitch I just noticed where the other levels disappear after finishing the first level. I just fixed that in my code

[sburrow]

Here I am again

I added better backgrounds! Got most of them from https://opengameart.org/, all of which I have are CC0, aka public domain.

I also added a 'wipe' function. Essentially it just fills the screen slowly from top to bottom with whatever background tiles I want. It looks pretty cool as a transition effect between screens, though to make it *perfect* I'd also have to 'unwipe' which would be nasty to program.

And lastly I put in a new 'intro scene' though at this point it only says "Your kitty floated away! Get your kitty back!" I will add more to it later.

Besides a nicer intro scene, remodeled sprites, and audio, this is essentially done. Everything I wanted to have is included.

Thanks everyone.

Chad

[sburrow]

Howdy again! Lots going on today.

Rename TOBUNES.S to TOBUNES.NES and play on your favorite emulator!

Though the 'story' page is a bit weak, the rest of this thing is awesome. I implemented the possibility of an additional skin for the character, essentially "Tobu Tobu Boy". Though I don't have the sprites drawn yet, the code is done. I also added some neat little sprites when you finally reach your kitty, things that make it a bit more polished looking.

I'm super proud of this game. It has really come together, especially today. I think the story page can use a tiny bit of work, but other than that, I just need to redo the sprite artwork, then audio, that's it. In total at this point the game and all data uses ~7KB of data, out of 32KB available for NROM NES cartridge. That leaves me *plenty* of space for at least 5 or 6 distinct sound tracks and some sound effects, I hope!

Now I have to learn pixel art and NES sound! That will be an adventure Thanks everyone.

Chad

EDIT: Added a GIF of gameplay, couldn't help myself

[sburrow]

Alright! I changed ALL of the sprite artwork, did it all by hand, myself, today. I learned a lot! And it doesn't look great! But that's fine for now!

And because I am now not using the 'stolen' art assets, I can post this to GitHub. Here it is!

https://github.com/stevenchadburrow/TobuNES

Still more to get done, but this was a major milestone. Thanks everyone!

Chad

[sburrow]

Hello again everyone!

The game is essentially finished! https://github.com/stevenchadburrow/TobuNES

You must rename TOBUNES.S to TOBUNES.NES in order to play in your NES emulator!

What I've been busy doing is learning music theory and creating songs from BMP files. See attached. The 'Composer' program converts the BMP into HEX, containing the note and duration essentially. My program then pushes that data onto the Pulse2, Triangle, and Noise channels. Pulse1 was reserved for sound effects, which was a fantastic decision! I cannot attach audio-type files here, but if you are interested in my audio journey, I have more information on the NesDev.org Forum, here: https://forums.nesdev.org/viewtopic.php?p=306064

Well, that's it! I'm done! Now what??? Probably another game.

Thank you everyone!

Chad

[6502inside]

More games are always welcome!