Adds 3D line/ribbon mesh capabilities.
Supports Godot 4.1.
The included LinePath3D node uses the Path3D node as a source of line segments;
you can use it to easily make a smooth line.
How to make a path?
Select the `LinePath3D`, then hold Ctrl (Cmd if on a Mac) and click to create points.To add handles to a point, hold Shift and click-and-drag on a point to add curve handles to it.
The included Line3D node more or less behaves like the stock Line2D.
Push your line points to it and a line mesh will be automatically generated.
The included Trail3D node forms a trail. This node will form line segments from
its previous positions. It works in global space, so it works as a child of another Node3D.
These nodes render lines in the same manner, and all support the same shaders.
Within addons/godot-polyliner/shaders/ is a bunch of ready-made line shaders,
from a cylinder facsimile to a full raymarched metal chain or swirling rope,
and from a blooming light tube to a swooshing effect.
(don't forget to make your shaders unique before editing them!)