GodotComponentTest/utils/Plane2D.cs

using System;
using Godot;

namespace GodotComponentTest.utils;

public class Plane2D
{
    public static readonly float DistancePrecision = 1.0e-5f;

    private Vector2 _planePoint;
    public Vector2 Normal;

    public Plane2D(Vector2 planePoint, Vector2 normal)
    {
        _planePoint = planePoint;
        Normal = normal;
    }

    public float DistanceToPoint(Vector2 point)
    {
        return (point - _planePoint).Dot(Normal);
    }

    public bool IsParallelToDir(Vector2 dir)
    {
        float normalDotDir = Normal.Dot(dir);

        return (Mathf.Abs(normalDotDir) <= Plane2D.DistancePrecision);
    }

    public float DistanceToLineSegment(Vector2 point, Vector2 dir)
    {
        float normalDotDir = Normal.Dot(dir);

        if (Mathf.Abs(normalDotDir) > Plane2D.DistancePrecision)
        {
            return (_planePoint.Dot(Normal) - point.Dot(Normal)) / normalDotDir;
        }

        if (normalDotDir < 0)
        {
            return Single.PositiveInfinity;
        }

        return Single.NegativeInfinity;
    }
}