Simulating Capillary Action in a WebGL Shader for a UI Press Effect

Most "ink spreading" effects on the web are the same three ingredients: a radial-gradient, a blur filter, and an opacity transition on a timer. They look fine. None of them are dye, and none of them move like dye. I wanted to see what changed if the effect actually followed the physics of a fluid wicking through cloth, so I built it as a real-time...