Grows a procedural tree skeleton — trunk, branches and twigs, each swept as a tapered tube — and bakes it into one non-indexed BufferGeometry (position and normal only), ready to instance into a forest. It produces branches only; add foliage as a separate layer.
The branching is deterministic for a given seed: a recursive sweep lays down gently
curved tubes with a parallel-transport frame (so they never twist), forking by the
pipe model (each child much thinner than its parent), spreading children along the
upper part of each branch with a golden-angle roll, and pulling them back up toward
the light. A flared root, non-linear taper and gravity droop fill in the character.
Parameters are set with a fluent builder: a set<Param>() exists for every default
( setSeed, setLevels, setChildren, … ), each returning this for chaining.
Each build() returns a fresh, independent mesh that the caller owns, so one
generator can be re-parametrized and built repeatedly to grow a varied stand:
const generator = new TreeGenerator( material );
const oak = generator.setSeed( 1 ).setLevels( 4 ).build();
const pine = generator.setSeed( 2 ).setLevels( 5 ).build();