CSGPolygon path mesh has stair-stepping when far away from the world origin

[AntonioNoack]

Godot version:
3.2.3 stable, mono, official

OS/device including version:
Windows 10
Ryzen 5 2600
RX 580 8GB, GLES3

Issue description:
Meshes from paths have stair stepping, so a zig-zag-behavior, when they have sharp curves, and go upwards. The farther the control points are from their origin point, the stronger the effect is.

Steps to reproduce:
Create a path
Add a CSG Polygon, using "Path" Mode as a child of the path
Create some points: create a curve (90° or sth like that), and the middle of the curve create a hill.
The path interval needs to be lower than 1. (best 0.1)
I am not sure, when exactly it occurs... maybe only with long paths?
You can see the issue in the sample project.

Minimal reproduction project:

PathStairs.zip

[Calinou]

This is a floating-point precision error, and I'm not sure if we can do anything about it. Such is the nature of floating-point computations…

Perhaps switching to double-precision floats in the CSG code would help, but it will also have a non-negligible performance impact.

[fire]

Manifold CSG now uses double precision internally.

#94321

[fire]

Result looks ok to me