The atoll. A barrier reef with one pass, five motus, and a lagoon full of coral knolls. |
Pier head, 18:00. The sun and moon track a real latitude, 16.5° south, the latitude of Bora Bora. |
The reef. Six scanned coral species, each colony with its own levels of detail. |
The bungalows. The lagoon refracts and glitters. It is the same ocean simulation that runs past the reef. |
A squall. The weather changes by itself: trade clouds, overcast, rain and thunder. |
Night. The swash and every wake glow with bioluminescence, under a waxing moon and the stars. |
Saltwater Village. Palms lean out over the sea, and the shade under them is warm. |
The lookout. A switchback trail climbs to a shelf 180 m up. |
## What is in it
**The sea**
- An FFT ocean with three cascades of 256², drawn on a CDLOD grid.
- Shore waves come from a jump-flood distance field of the coastline. They shoal over the reef, break, run up the sand as swash and leave it wet.
- A ripple simulation adds the wakes of boats, swimmers and animals.
- Refraction absorbs light along the depth of whatever each pixel actually shows, so knoll edges stay clean.
- Under water there are caustics and light shafts. When you surface, the lens holds drops of water that slide off.
**The island**
- One GPU-generated heightfield (3.6 km across, 2048²) is read back once and then used for walking, placing objects and buoyancy.
- Mount Halcyon is [Ōlomana](https://en.wikipedia.org/wiki/Olomana), from the USGS 1 m lidar survey of O'ahu. It is scaled to 0.68, so its slopes stay true, and turned so that its single-pyramid face looks at the harbour.
- The ground is layered by a vegetation map rather than by height: beach, sandy soil, kept lawn, rank grass, leaf litter only under closed canopy, and triplanar cliffs.
**The plants**
- 24 species, 43,000 instances, all from photoreal scans.
- Full geometry up close with dithered LOD bands, and hemi-octahedral impostors in the distance.
- Shadow-only meshes skip the main pass entirely.
**The reef**
- About 370,000 instanced colonies of six scanned coral species.
- Each colony gets four levels of detail and its own frustum culling.
- Fish schools swim in the vertex shader; the CPU replays the same path to choose each fish's level of detail.
**The life**
- Humpbacks that blow and breach, a dolphin pod, turtles, mantas and blacktip sharks.
- Gulls and frigatebirds overhead, crabs that bolt for the water when you come close, and fireflies after dark.
**The sky and light**
- Single-scattering atmosphere; ray-marched cumulus at half resolution with reprojection; cirrus, stars and a moon with phases.
- Sun and moon follow a real latitude of 16.5° south.
- An HDR pipeline with MSAA; half-resolution GTAO that occludes only sky light and bounce; bloom, sun shafts and ACES.
**The sound**
- Generated live with Web Audio rather than played from loops: surf scaled by your distance to the break, wind, birds by day, crickets by night, rain, and whale song under water.
**The smoothness**
- Every shader is compiled and every texture uploaded before the title fades.
- HD textures stream in over several frames.
- A frame-time governor trades render scale for a steady 60 fps.
- Phones get touch controls and a lighter asset tier.
## Controls
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