Renderer · interface

CausticSheet

A surface lit by nearby water: the floor of a pool, the bottom of a flooded corridor, the underside of a bridge, an arch, a jetty, a cave mouth.

Explained in Hello world.

interface CausticSheet

import type { CausticSheet } from '@driftengine/core';

In depth

The caller submits the lit surface and says which body of water is throwing the light. Everything else — where the light lands, how sharp the net is, how it moves — comes from the wave field in shaders/gerstner.ts, which is the same field the water surface itself is displaced by.

Either side of the surface works. The overhead case came first and passed for the whole feature for a while, but a pool floor is the same optics and by far the more ordinary sight; the sheet simply lies under the water instead of over it.

Properties

Name	Type	Description
`spans`	`readonly SheetSpan[]`	Cross-sections of the lit surface, in order.
`waterY`	`number`	Resting height of the water throwing the light. More Per sheet rather than per draw, so one batch can carry surfaces above and below water at different heights — and so a caller cannot forget to keep the two in step, which is the whole contract of this feature: the pattern is only worth having because it is the crests the player can see.