water_surfaces

The water surfaces a scene holds, gathered from the systems that make them. A system with water — a terrain's lakes, rivers and seas, an ocean — registers a provider here, and whatever stands things on water asks every provider at once. A procedural graph reads them all through scene.water.

A provider is a table of two functions:

• version() names what its water is now. A surface that moves every frame answers differently every frame, which is what makes a reader stand its points again.

• stand(request) puts points on its water on the device. request holds:

  • run: the points' GPU positions, in the graph's space;
  • count: how many points there are;
  • out: the P, normal, slope and wet GPU columns to write;
  • place / unplace: graph to world and back, 16 numbers each;
  • offset: metres above the surface;
  • keepY: whether a point's own height rides on the surface's.

  It writes the points over its water, leaves the rest as they are, and returns the names of the kernels it dispatched.

local water = require("@builtin::modules.water_surfaces")
water.register("myWater", { version = versionNow, stand = standOnMyWater })
for _, p in water.list() do
    print(p.name, p.provider.version())
end