Discussion
heyitsgarrett: 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.
Lambdanaut: 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..Maybe using wave function collapse:> https://nathanmcoleman.com/projects/wavecollapse/
Klonoar: This is amazing.Could you add support for holding `Shift` to keep your line straight while painting, ala MSPaint?
olivia-banks: This is a seriously fun tool. Bravo!
adammarples: In what way is a brush a program? How do I program it? I've spent 5 minutes and clicked on every single thing I can find but I give up looking.
jammaloo: Click "Editor", then click "Add a brush".
azeirah: 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!Maybe this can give you some inspiration!https://laura.fm/generative-art/wind/wind.html
graypegg: That's such a neat idea! It's like a paintable version of https://www.shadertoy.comIs 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
vunderba: Very cool. Side note, but I've always thought that a combination of a pixel art editor like Aseprite coupled "cellular sand sim" would be really cool.
heyitsgarrett: Added that! Great idea. Hold shift before or during a line draw and it will preview the line, then apply on release.
lukevp: Cool concept!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.
heyitsgarrett: 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!
b1temy: Very cool!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.
cc-d: very cool this one is mine https://play.moss.town/gallery/weekly-d20962c2-eb48-433f-90d...really love the site design, great job man
jpereira: Love this! A couple things it'd be really fun to see:- timelapses of things being drawn- a list of brushes used in a drawingTo get even wilder, what if you could record brush strokes and then retroactively change the brush code and replay them?
tomgp: 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.
flexagoon: Really cool, reminds me of TodePond videos
Latitude7973: This is very nice. I am astounded that my Surface Pro stylus works well with the brushes, even using pressure data. And all in the browser!
dnpls: 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.
smusamashah: 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?
frisia: This was very interesting to read! My choice of drawing program now is Rebelle, which does have a "swarm" brush (they call them bristle brushes, designed to emulate real paintbrushes) and together with its physical simulation where paint applied on the canvas has a thickness instead of opacity, the results can look absolutely stunning. Have given me the itch to also experiment with simulation-based drawing programs.
BloodOverdrive: I didn't catch it, maybe some tutorial how to use it properly.
qubidt: Do you have a link to the youtube channel? "SWEet" isn't really searchable
seism: You made my day. Thank you!
b1temy: The video in question:-https://youtu.be/_mL1uaOgGvcAlthough the channel is indeed called SWEet, I should have given the YouTube channel handle, SWEetOverflows.
