unity-atoms/Assets/UnityAtoms/Utils/Vector2Utils.cs

using System.Collections;
using System.Collections.Generic;
using UnityEngine;

namespace UnityAtoms.Utils
{
    public static class Vector2Utils
    {
        // Find out if two lines intersect
        public static bool IsIntersectingAlternative(Vector2 p1, Vector2 p2, Vector2 p3, Vector2 p4)
        {
            float denominator = (p4.y - p3.y) * (p2.x - p1.x) - (p4.x - p3.x) * (p2.y - p1.y);
            if (denominator != 0)
            {
                float u_a = ((p4.x - p3.x) * (p1.y - p3.y) - (p4.y - p3.y) * (p1.x - p3.x)) / denominator;
                float u_b = ((p2.x - p1.x) * (p1.y - p3.y) - (p2.y - p1.y) * (p1.x - p3.x)) / denominator;
                if (u_a >= 0 && u_a <= 1 && u_b >= 0 && u_b <= 1)
                {
                    return true;
                }
            }
            return false;
        }
    }
}