Curl of a 2D scalar noise potential - a divergence-free (incompressible) flow
field. Particles advected through it swirl like a fluid and never converge to
sinks or fly apart, which is why it's the cheap go-to for procedural smoke /
flow. Given a scalar potential psi(x, y), the flow is (d psi/dy, -d psi/dx),
with the derivatives taken by central differences of step eps.
Curl of a 2D scalar noise potential - a divergence-free (incompressible) flow field. Particles advected through it swirl like a fluid and never converge to sinks or fly apart, which is why it's the cheap go-to for procedural smoke / flow. Given a scalar potential psi(x, y), the flow is (d psi/dy, -d psi/dx), with the derivatives taken by central differences of step
eps.