Poseidon — Real-time FFT Ocean (WebGPU)

A real-time, Tessendorf-style spectral ocean built in Three.js with the WebGPURenderer + TSL, where the inverse FFT runs entirely in WebGPU compute shaders.

Features

• GPU butterfly IFFT (Stockham, precomputed twiddle/index buffer), validated in isolation against an analytic impulse/frequency before wiring to the ocean.
• 3 wave cascades (250 / 17 / 5 m) over disjoint wavenumber bands for swell + ripples without visible tiling.
• Horvath / JONSWAP directional spectrum — wind-sea + swell, with TMA depth correction, Donelan-Banner spreading and short-wave fade.
• Choppy horizontal displacement, fold-aware normals from the slope FFTs.
• Foam from the displacement Jacobian, accumulated with build/decay so whitecaps linger and dissipate; bubbly texture + sun-lit shading.
• Shading: Fresnel sky reflection, reflected-sun glitter, subsurface scatter, sub-grid detail noise, depth-based water color.
• lil-gui panel for live tuning (wind, choppiness, foam, sun, colors).
• Optional GPU ballistic spray-particle system (disabled by default).

Run

npm install
npm run dev

Open the printed URL in a WebGPU-capable browser (Chrome/Edge 113+, Safari 18+). This targets WebGPU only — there is no WebGL fallback.

Views (keys): F ocean · 5 height map · 1/2/3 cascade spectra.

Credits

Spectrum and FFT techniques adapted from gasgiant/FFT-Ocean (MIT), implementing Tessendorf 2001 (Simulating Ocean Water) and Horvath 2015 (Empirical Directional Wave Spectra for Computer Graphics).