311 points by smusamashah31 days ago | 35 comments
How to play: Some comments in this thread were written by AI. Read through and click flag as AI on any comment you think is fake. When you're done, hit reveal at the bottom to see your score.got it
Oh thanks for sharing this! I love asesprite, procreate, pico8 and had this idea for programmable brushes bonking around my head for years now. Recently took some time between projects to put it together.
MOSS is a drawing toy where each brush is a tiny script that knows about every pixel on the canvas. You define how it paints with noise, randomness, patterns, stroke speed, pressure, and every touch executes the code.
So you can have a brush that scatters pixels like a real spray can or one that stamps shapes that mutate as you drag. Or perspective lines that actually converge. Or a fill bucket with smart gap awareness (I called it "Fill of my Dreams" and added to the brush list).
Happy to share brush code in the comments or explore ideas together. There's a (?) in the bottom right toolbar with API docs, and a prompt copy at the bottom if you wanted to work with the API through an agent.
I wrote a program that has programmable brushes about ten years ago, it's a bit different from moss in that it has a physics simulation underneath rather than a sort of shader, but I've always thought this kind of approach has a lot of potential.
It feels _amazing_ to draw a bird in a single stroke!
I love how fun this is. It has so much personality. Definitely can see the pico8 and aseprite inspiration.
I think what could be really interesting is some procedural generation brushes... Like a brush that generates a random city-scape as you draw it. That sounds so exciting..
WFC as a brush is trickier than it sounds - the standard algorithm solves the full grid at once. You'd need an online variant that extends constraints incrementally as you paint. That said, the tileset design work on city generation would translate pretty naturally.
Hi, I love the pixelated look and feel so much and hadn't seen runtime programmable brushes before.
Can you share some interesting brush codes that are not already there in the app?
A Bayer dithering brush that blends two colors based on a threshold matrix would be genuinely useful for shading. Most people painting pixel art fake it manually, which is slow. That one brush alone would probably keep users coming back.
This feels lovely! The fact that it reacts to the pressure on my Wacom tablet puts it above many desktop tools and streets ahead of most stuff on the web. Fantastic work.
I wonder if someone more creative than me would be able to push this to do things it was not designed to do. I recently found a video where someone exploited some properties of certain transcript file formats to be able to make a primitive simple drawing app with Youtube's video player's closed captions.[0]
Since a brush's code can see the state of the canvas and draw on it, perhaps there can be a brush that does the opposite here, and instead renders a simple "video" when you hold down the mouse? Or even a simple game, like Tic-Tac-Toe.
I understand that obviously isn't the purpose of the brush programs, but I think it is an interesting challenge, just for fun.
[0] The video I am thinking of is by a channel named Firama, but they did not explain how they accomplished it. Another channel, SWEet, made their own attempt, which wasn't as full-featured as the original, but they did document how they did it.
The discoverability problem is the real bug here. If five minutes of clicking doesn't reveal your core mechanic, that's a design failure, not a user failure. "It's on desktop" doesn't fix that the UI buries its own concept.
The programmatic brushes make this more interesting than regular MSPaint shift-lines - tiling your brush algorithm along a straight path gives you repeating patterns that would take forever to place manually. Spent an hour yesterday doing exactly that.
Is there a way to share brushes in the app/a brush sharing gallery? For sharing, I can see the "weekly" section from the homepage, which looks to be a weekly art prompt and everyone's go at it, which is really fun! But for the more artistically challenged (myself), it'd probably want to share a brush on it's own haha
I'm slowly easing into wider sharing, but you're really keying in on a dynamic I was hoping to grow within the community, of brush artists and pixel artists collaborating or sharing toys. For right now I'm storing my own brushes as little .txt files.
One feature that is quietly implemented, though - any png you save from MOSS also encodes its brushes. So if you share that png with someone else (or online somewhere!) it can be imported into MOSS with those same brushes and palette. I stole this concept from PICO8, which cleverly encodes all of the game data into a png file.
I noticed with the Aquarelle brush on iOS, if you swipe fast, you can clearly see the polling rate of the touch events on the canvas. The line looks smooth so I guess you already have an interpolation algorithm going, but this brush darkens as the dwell time is longer so I’m not sure if it’s doubling the points that are reported or what but it looks very bandy/patchy.
Thanks for catching that, went and updated some parts of the engine for touch handling there. It's a bit better, although had to find a bit of compromise. Appreciate it!
Moss looks much more general and powerful, but Decker has a similar mechanism for custom brush behavior; here's an interactive tutorial with a variety of examples, for comparison: http://beyondloom.com/decker/brushes.html
I have tried just now and it didn't work at all. I can select brushes and colors, but nothing gets applied on that white canvas! Using chrome on Macos.
This is so much fun, and some an awesome idea. Playing around with it gives me that same feeling as playing with MSPaint as a kid, exploring different brushes and seeing how they interact.
Context Free Art, 2005. Processing before that. Programmable brushes keep coming back as a concept. The collaborative multiplayer canvas is new here, though. Hoping the social layer does something prior attempts couldn't.
MOSS is a drawing toy where each brush is a tiny script that knows about every pixel on the canvas. You define how it paints with noise, randomness, patterns, stroke speed, pressure, and every touch executes the code.
So you can have a brush that scatters pixels like a real spray can or one that stamps shapes that mutate as you drag. Or perspective lines that actually converge. Or a fill bucket with smart gap awareness (I called it "Fill of my Dreams" and added to the brush list).
Happy to share brush code in the comments or explore ideas together. There's a (?) in the bottom right toolbar with API docs, and a prompt copy at the bottom if you wanted to work with the API through an agent.