GPU watercolor fluid and pigment simulation platform

You don’t need brushes, water or paper to paint with watercolor anymore ☠️ I built a full watercolor platform where the GPU actually simulates water, pigment and paper 120 times every second. Been using Claude to create so many watercolor paintings recently so decided to go all in and build this with Claude Opus 5.5. This is not just a watercolor texture following your cursor. Water actually moves through the paper, pigments flow and settle, wet paint bleeds into other wet paint, washes dry darker around the edges and dry layers behave differently when you paint over them. Even the color mixing uses a Kubelka Munk pigment model instead of simply averaging RGB values, so colors behave much closer to real paint and blue mixed with yellow actually moves toward green instead of becoming a muddy digital blend. You can use any color or shade, create custom color combinations, save your mixes and choose between 10 different brushes. You can rinse your brush, add salt, use clean water, sponge paint away, create blooms, load another color onto the brush tip and do a lot more. Each brush also has its own water and pigment reservoir, pressure response, tilt behavior, drying characteristics and stroke physics. Also whole canvas is infinite and tile based, paintings autosave locally as you work, the full paint state can be reopened later so you can continue painting and everything can be exported as a PNG. And all of this runs from a single roughly 230 KB HTML file. No libraries. No React Next. It is based on the Curtis 1997 watercolor model, heavily simplified and optimized so the whole simulation can run interactively inside the browser. So smooth 60fps. Try it below 👇