city-generation/Game/Assets/Scripts/Utils/Algorithms.cs

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using TransportGame.Model;

namespace TransportGame.Utils
{
    public static class Algorithmss
    {
        public static bool DoPolygonsIntersect(Vector2[] a, Vector2[] b)
        {
            foreach (var poly in new[] {a, b})
            {
                for (int i = 0; i < poly.Length; i++)
                {
                    int j = (i + 1) % poly.Length;

                    var normal = new Vector2(poly[j].Y - poly[i].Y, poly[i].X - poly[j].X);
                    
                    double? minA = null, maxA = null;
                    foreach (var p in a)
                    {
                        var projected = Vector2.Dot(normal, p);
                        if (minA == null || projected < minA)
                            minA = projected;
                        if (maxA == null || projected > maxA)
                            maxA = projected;
                    }

                    double? minB = null, maxB = null;
                    foreach (var p in b)
                    {
                        var projected = Vector2.Dot(normal, p);
                        if (minB == null || projected < minB)
                            minB = projected;
                        if (maxB == null || projected > maxB)
                            maxB = projected;
                    }

                    if (maxA <= minB || maxB <= minA)
                        return false;
                }
            }

            return true;
        }
    }
}