CtrEditor/Simulacion/InterseccionCirculoRectangulo.cs

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Threading.Tasks;
using Microsoft.VisualBasic.Devices;
using nkast.Aether.Physics2D.Common;

namespace CtrEditor.Simulacion
{
    internal class InterseccionCirculoRectangulo
    {
        // Definición de la función CalcularSuperficieCompartida
        public static float CalcularSuperficieCompartida(Vector2[] vertices, Vector2 center, float radio)
        {
            float totalCircleArea = (float) (Math.PI * radio * radio);

            // Distancia a líneas ajustado
            float[] distances = new float[4];
            for (int i = 0; i < 4; i++)
            {
                distances[i] = DistanceFromLine(center, vertices[i], vertices[(i + 1) % 4]);
            }

            float minDistance = float.MaxValue;
            foreach (var dist in distances)
            {
                if (Math.Abs(dist) < Math.Abs(minDistance))
                    minDistance = dist;
            }
            float d = Math.Abs(minDistance);

            float sharedArea = 0;
            if (Array.TrueForAll(distances, dist => Math.Abs(dist) > radio))
            {
                sharedArea = totalCircleArea;
            }
            else if (d < radio)
            {
                float cosTheta = Math.Min(1, d / radio);
                float sinTheta = (float)Math.Sqrt(Math.Max(0, radio * radio - d * d));
                if (minDistance < 0) // El centro está dentro del rectángulo
                {
                    float areaOutside = radio * radio * (float)Math.Acos(cosTheta) - d * sinTheta;
                    sharedArea = totalCircleArea - areaOutside;
                }
                else // El centro está fuera del rectángulo
                {
                    sharedArea = radio * radio * (float)Math.Acos(cosTheta) - d * sinTheta;
                }
            }
            else
            {
                sharedArea = 0;
            }
            var area = (sharedArea / totalCircleArea) * 1.1f;
            return area > 1 ? 1 : area;  
        }

        public static float DistanceFromLine(Vector2 point, Vector2 start, Vector2 end)
        {
            float A = end.Y - start.Y;
            float B = start.X - end.X;
            float C = end.X * start.Y - start.X * end.Y;
            float distance = (A * point.X + B * point.Y + C) / (float)Math.Sqrt(A * A + B * B);
            return distance;
        }

    }

}