hckrnws
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!
Maybe this can give you some inspiration!
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.
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:
That's such a neat idea! It's like a paintable version of https://www.shadertoy.com
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
This is amazing.
Could you add support for holding `Shift` to keep your line straight while painting, ala MSPaint?
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
This is the most fun I’ve had drawing with pixels since I was a kid
Absolutely lovely design, thanks for the share and the inspiration
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.
It's way cooler on desktop than mobile.
If you hover next to the brush in the Edit mode as well, theres a tiny pencil icon there that opens that brush's code. Sorry it was hard to discover!
Click "Editor", then click "Add a brush".
This is a seriously fun tool. Bravo!
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Crafted by Rajat
Source Code