# FFT ocean

an open sea driven by a Tessendorf spectrum, not analytic waves.

```{raw} html
<a class="example-run-button" href="../demos/features_3d_ocean.html">▶ Run in browser</a>

```

**Tags:** `3d` `ocean` `fft` `water` `transparent`

An OceanSurface3D is a built-in transparent pass (design D11) that reuses the
WaterMaterial shading of the Gerstner water pass but replaces the analytic vertex
displacement with a sampled FFT displacement map: a Phillips spectrum with the
WorldEnvironment wind, inverse-transformed each frame into per-cascade
displacement, slope and foam. Three cascades (long swell / mid chop / fine
ripple) sum into a believable open sea: rolling swell, choppy crests, foam laced
onto the steep folding faces, sun glint tracking the wind, and depth-faded
refraction of the submerged island. The cascade texture size + count come from
the graphics quality tier.


Usage:
    uv run python examples/features/3d/ocean.py

## Source

```{literalinclude} ../../examples/features/3d/ocean.py
:language: python
:linenos:
```