Metaballs

A simple implementation of Metaballs.

How it works

Each metaball is defined by a position, radius/strength and a falloff function

For each pixel we calculate the density by summing the values of the falloff function for that pixel. The further from the centre of a metaball a pixel is, the lower the value, and this falls off proportional to 1/r^2.

This strength value will add to the density of that pixel, which is then represented using the brightness of the pixel. This gives you extremely high values close to the metaball, which fall off very fast, and we can then threshold these to produce clean lines

I thought it would be interesting if I implemented negative strengths so each metaball has a 50/50 chance of being negative, which will subtract from the density instead of adding.