www.pudn.com > IntroductionTo3DGameEngineDesign.rar > Math.cs

using System; 
using System.Drawing; 
using Microsoft.DirectX; 
using Microsoft.DirectX.Direct3D; 
 
namespace GameEngine 
{ 
	/// 
 
	/// Summary description for GameMath. 
	/// 
 
	public class GameMath 
	{ 
		public GameMath() 
		{ 
			// 
			// TODO: Add constructor logic here 
			// 
		} 
 
		public static Vector3 ComputeFaceNormal( Vector3 p1, Vector3 p2, Vector3 p3 ) 
		{ 
			Vector3 Normal; 
 
			Vector3 V1 = Vector3.Subtract(p1,p2); 
			Vector3 V2 = Vector3.Subtract(p3,p1); 
			Normal = Vector3.Cross( V1, V2 ); 
			Normal.Normalize(); 
 
			return Normal; 
		} 
 
		public static bool InRect( Rectangle rect, Vector3 pt) 
		{ 
			bool inside =  pt.X >= rect.Left && pt.X <= rect.Right &&  
				           pt.Z >= rect.Bottom && pt.Z <= rect.Top; 
 
			return inside; 
		} 
	} 
}