Platformer2D/Platformer2D.Core/Game/Circle.cs

   1 #region File Description
   2 //-----------------------------------------------------------------------------
   3 // Circle.cs
   4 //
   5 // Microsoft XNA Community Game Platform
   6 // Copyright (C) Microsoft Corporation. All rights reserved.
   7 //-----------------------------------------------------------------------------
   8 #endregion
   9
  10 using System;
  11 using Microsoft.Xna.Framework;
  12
  13 namespace Platformer2D
  14 {
  15     /// <summary>
  16     /// Represents a 2D circle.
  17     /// </summary>
  18     struct Circle
  19     {
  20         /// <summary>
  21         /// Center position of the circle.
  22         /// </summary>
  23         public Vector2 Center;
  24
  25         /// <summary>
  26         /// Radius of the circle.
  27         /// </summary>
  28         public float Radius;
  29
  30         /// <summary>
  31         /// Constructs a new circle.
  32         /// </summary>
  33         public Circle(Vector2 position, float radius)
  34         {
  35             Center = position;
  36             Radius = radius;
  37         }
  38
  39         /// <summary>
  40         /// Determines if a circle intersects a rectangle.
  41         /// </summary>
  42         /// <returns>True if the circle and rectangle overlap. False otherwise.</returns>
  43         public bool Intersects(Rectangle rectangle)
  44         {
  45             Vector2 v = new Vector2(MathHelper.Clamp(Center.X, rectangle.Left, rectangle.Right),
  46                                     MathHelper.Clamp(Center.Y, rectangle.Top, rectangle.Bottom));
  47
  48             Vector2 direction = Center - v;
  49             float distanceSquared = direction.LengthSquared();
  50
  51             return ((distanceSquared > 0) && (distanceSquared < Radius * Radius));
  52         }
  53     }
  54 }