buildMesh method

@override ShapeMesh buildMesh([ ShapeUv uv = ShapeUv.natural ])

Its triangles, textured by uv.

Implementation

@override
ShapeMesh buildMesh([ShapeUv uv = ShapeUv.natural]) {
  final r = Primitive3D.size(radius), c = _half;
  final n = Primitive3D.count(rings, 1, 32);
  final cap = uv.anyway(r * math.pi / 2);
  final straight = uv.alongY(c * 2);
  final profile = <(double, double, double, double, double)>[];
  for (var j = 0; j <= n; j++) {
    final t = math.pi / 2 * j / n;
    profile.add((
      r * math.sin(t),
      -c - r * math.cos(t),
      math.sin(t),
      -math.cos(t),
      uv.anyway(r * t),
    ));
  }
  for (var j = 0; j <= n; j++) {
    final t = math.pi / 2 + math.pi / 2 * j / n;
    profile.add((
      r * math.sin(t),
      c - r * math.cos(t),
      math.sin(t),
      -math.cos(t),
      cap + straight + uv.anyway(r * (t - math.pi / 2)),
    ));
  }
  final b = MeshBuilder(uv)
    ..lathe(
      profile,
      Primitive3D.count(segments, 3, 128),
      aroundLength: uv.around(r),
      profileLength: cap * 2 + straight,
    );
  final mesh = b.build();
  return smooth ? mesh : mesh.faceted();
}