Fluid dynamics is a real-time fluid simulation you paint with your finger. Under the hood it solves the same equations that describe real smoke and water — the Navier–Stokes equations — entirely on the GPU using WebGL2, so thick, swirling dye reacts to every stroke at full frame rate.
How it works. Every frame the app runs a chain of GPU shader passes over floating-point textures. It first computes the fluid's curl and adds a vorticity force to keep the motion lively and turbulent, then makes the flow incompressible by solving for pressure over roughly twenty iterations and subtracting its gradient from the velocity field. The velocity and the coloured dye are then advected — carried along the flow — and both fade slightly each step so trails dissipate naturally. The simulation runs on a compact velocity grid while the dye is rendered at much higher resolution for crisp detail, with a lighting pass that shades the fluid from its own density gradients to give it depth.
How you interact:
- Draw — drag anywhere to inject dye and push the fluid; the direction and speed of your stroke become the force applied, and the colour drifts through the rainbow as you move. Multi-touch is supported, so several fingers stir at once.
- Burst — fires several randomly aimed splats of colour and force into the field for an instant explosion of motion.
- Particles — toggles a layer of ~16,000 GPU particles that ride the velocity field, brightening where the flow moves fastest, then wrap and respawn to keep coverage even.
- Full screen — expands the canvas edge-to-edge.
Everything runs locally with no network access, and the app automatically probes the device for the best supported float texture formats so it degrades gracefully across GPUs.