TrueCraft/TrueCraft.API/BoundingBox.cs

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

namespace TrueCraft.API
{
    public enum ContainmentType
    {
        Disjoint,
        Contains,
        Intersects
    }

    // Mostly taken from the MonoXna project, which is licensed under the MIT license
    public struct BoundingBox : IEquatable<BoundingBox>
    {
        #region Public Fields

        public Vector3 Min;
        public Vector3 Max;
        public const int CornerCount = 8;

        #endregion Public Fields


        #region Public Constructors

        public BoundingBox(Vector3 min, Vector3 max)
        {
            this.Min = min;
            this.Max = max;
        }

        public BoundingBox(BoundingBox b)
        {
            this.Min = new Vector3(b.Min);
            this.Max = new Vector3(b.Max);
        }

        #endregion Public Constructors


        #region Public Methods

        public ContainmentType Contains(BoundingBox box)
        {
            //test if all corner is in the same side of a face by just checking min and max
            if (box.Max.X < Min.X
                || box.Min.X > Max.X
                || box.Max.Y < Min.Y
                || box.Min.Y > Max.Y
                || box.Max.Z < Min.Z
                || box.Min.Z > Max.Z)
                return ContainmentType.Disjoint;


            if (box.Min.X >= Min.X
                && box.Max.X <= Max.X
                && box.Min.Y >= Min.Y
                && box.Max.Y <= Max.Y
                && box.Min.Z >= Min.Z
                && box.Max.Z <= Max.Z)
                return ContainmentType.Contains;

            return ContainmentType.Intersects;
        }

        public bool Contains(Vector3 vec)
        {
            return Min.X <= vec.X && vec.X <= Max.X &&
                Min.Y <= vec.Y && vec.Y <= Max.Y &&
                Min.Z <= vec.Z && vec.Z <= Max.Z;
        }

        public static BoundingBox CreateFromPoints(IEnumerable<Vector3> points)
        {
            if (points == null)
                throw new ArgumentNullException();

            bool empty = true;
            Vector3 vector2 = new Vector3(float.MaxValue);
            Vector3 vector1 = new Vector3(float.MinValue);
            foreach (Vector3 vector3 in points)
            {
                vector2 = Vector3.Min(vector2, vector3);
                vector1 = Vector3.Max(vector1, vector3);
                empty = false;
            }
            if (empty)
                throw new ArgumentException();

            return new BoundingBox(vector2, vector1);
        }

        /// <summary>
        /// Offsets this BoundingBox. Does not modify this object, but returns a new one
        /// </summary>
        /// <returns>
        /// The offset bounding box.
        /// </returns>
        /// <param name='Offset'>
        /// The offset.
        /// </param>
        public BoundingBox OffsetBy(Vector3 Offset)
        {
            return new BoundingBox(Min + Offset, Max + Offset);
        }

        public Vector3[] GetCorners()
        {
            return new Vector3[]
                       {
                           new Vector3(this.Min.X, this.Max.Y, this.Max.Z),
                           new Vector3(this.Max.X, this.Max.Y, this.Max.Z),
                           new Vector3(this.Max.X, this.Min.Y, this.Max.Z),
                           new Vector3(this.Min.X, this.Min.Y, this.Max.Z),
                           new Vector3(this.Min.X, this.Max.Y, this.Min.Z),
                           new Vector3(this.Max.X, this.Max.Y, this.Min.Z),
                           new Vector3(this.Max.X, this.Min.Y, this.Min.Z),
                           new Vector3(this.Min.X, this.Min.Y, this.Min.Z)
                       };
        }

        public bool Equals(BoundingBox other)
        {
            return (this.Min == other.Min) && (this.Max == other.Max);
        }

        public override bool Equals(object obj)
        {
            return (obj is BoundingBox) && this.Equals((BoundingBox)obj);
        }

        public override int GetHashCode()
        {
            return this.Min.GetHashCode() + this.Max.GetHashCode();
        }

        public bool Intersects(BoundingBox box)
        {
            bool result;
            Intersects(ref box, out result);
            return result;
        }

        public void Intersects(ref BoundingBox box, out bool result)
        {
            if ((this.Max.X >= box.Min.X) && (this.Min.X <= box.Max.X))
            {
                if ((this.Max.Y < box.Min.Y) || (this.Min.Y > box.Max.Y))
                {
                    result = false;
                    return;
                }

                result = (this.Max.Z >= box.Min.Z) && (this.Min.Z <= box.Max.Z);
                return;
            }

            result = false;
        }

        public static bool operator ==(BoundingBox a, BoundingBox b)
        {
            return a.Equals(b);
        }

        public static bool operator !=(BoundingBox a, BoundingBox b)
        {
            return !a.Equals(b);
        }

        public override string ToString()
        {
            return string.Format("{{Min:{0} Max:{1}}}", this.Min.ToString(), this.Max.ToString());
        }

        #endregion

        public double Height
        {
            get { return Max.Y - Min.Y; }
        }

        public double Width
        {
            get { return Max.X - Min.X; }
        }

        public double Depth
        {
            get { return Max.Z - Min.Z; }
        }

        public Vector3 Center
        {
            get
            {
                return (this.Min + this.Max) / 2;
            }
        }
    }
}