[image: Gerstner logo]

Gerstner

Pure Gerstner wave displacement for Roblox. One module and no Instances, no states. It takes wave definitions and returns surface positions.

Install

Wally:

[dependencies]
Gerstner = "superdupernairobi/gerstner@0.1.0"

Quickstart

local gerstner = require(game.ReplicatedStorage.gerstner)

local prepared = gerstner.prepare({
    { wavelength = 40, amplitude = 2, steepness = 0.5, direction = Vector2.new(1, 0) },
    { wavelength = 70, amplitude = 3, steepness = 0.4, direction = Vector2.new(0.7, 0.7) },
})

local position = gerstner.displace(prepared, x, z, t) -- Vector3

prepare validates and precomputes ONCE. displace is the hot path, call it PER vertex, per frame, against the same prepared value

Notes

• Studs. G is 196.2 studs/s^2, matching a scale of 20 studs per metre
• y is relative to the water plane. displace returns absolute X and Z, but y is measured from the planes own level, so your renderer adds sea level
• Reuse ONE prepared value. Never call prepare inside an update loop
• Buoyancy is an APPROXIMATION. Gerstner displaces horizontally, so "surface height at world (x, z)" is an inverse problem. Sampling displace(x,z) and taking y is a good approximation, not an exact answer. If you use it for physics, keep the authoritative lookup on the server

API

prepare, displace, Wave, Prepared - see the API ref

License

MIT