Monogame-Extended/source/MonoGame.Extended/Math/Angle.cs

/*
* -----------------------------------------------------------------------------
* Original code from SlimMath project. http://code.google.com/p/slimmath/
* Greetings to SlimDX Group. Original code published with the following license:
* -----------------------------------------------------------------------------
* 
* Copyright (c) 2007-2010 SlimDX Group
* 
* Permission is hereby granted, free of charge, to any person obtaining a copy
* of this software and associated documentation files (the "Software"), to deal
* in the Software without restriction, including without limitation the rights
* to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
* copies of the Software, and to permit persons to whom the Software is
* furnished to do so, subject to the following conditions:
* 
* The above copyright notice and this permission notice shall be included in
* all copies or substantial portions of the Software.
* 
* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
* IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
* FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
* AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
* LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
* OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
* THE SOFTWARE.
*/

using System;
using System.Diagnostics;
using System.Runtime.Serialization;
using Microsoft.Xna.Framework;

namespace MonoGame.Extended
{
    public enum AngleType : byte
    {
        Radian = 0,
        Degree,
        Revolution, //or Turn / cycle
        Gradian // or Gon
    }

    [DataContract]
    [DebuggerDisplay("{ToString(),nq}")]
    public struct Angle : IComparable<Angle>, IEquatable<Angle>
    {
        private const float _tau = (float) (Math.PI*2.0);
        private const float _tauInv = (float) (0.5/Math.PI);
        private const float _degreeRadian = (float) (Math.PI/180.0);
        private const float _radianDegree = (float) (180.0/Math.PI);
        private const float _gradianRadian = (float) (Math.PI/200.0);
        private const float _radianGradian = (float) (200.0/Math.PI);

        [DataMember]
        public float Radians { get; set; }

        public float Degrees
        {
            get => Radians*_radianDegree;
            set => Radians = value*_degreeRadian;
        }

        public float Gradians
        {
            get => Radians*_radianGradian;
            set => Radians = value*_gradianRadian;
        }

        public float Revolutions
        {
            get => Radians*_tauInv;
            set => Radians = value*_tau;
        }

        public Angle(float value, AngleType angleType = AngleType.Radian)
        {
            switch (angleType)
            {
                default:
                    Radians = 0f;
                    break;
                case AngleType.Radian:
                    Radians = value;
                    break;
                case AngleType.Degree:
                    Radians = value*_degreeRadian;
                    break;
                case AngleType.Revolution:
                    Radians = value*_tau;
                    break;
                case AngleType.Gradian:
                    Radians = value*_gradianRadian;
                    break;
            }
        }

        public float GetValue(AngleType angleType)
        {
            switch (angleType)
            {
                default:
                    return 0f;
                case AngleType.Radian:
                    return Radians;
                case AngleType.Degree:
                    return Degrees;
                case AngleType.Revolution:
                    return Revolutions;
                case AngleType.Gradian:
                    return Gradians;
            }
        }

        public void Wrap()
        {
            var angle = Radians%_tau;
            if (angle <= Math.PI) angle += _tau;
            if (angle > Math.PI) angle -= _tau;
            Radians = angle;
        }

        public void WrapPositive()
        {
            Radians %= _tau;
            if (Radians < 0d) Radians += _tau;
            Radians = Radians;
        }

        public static Angle FromVector(Vector2 vector)
        {
            return new Angle((float) Math.Atan2(-vector.Y, vector.X));
        }

        public Vector2 ToUnitVector() => ToVector(1);

        public Vector2 ToVector(float length)
        {
            return new Vector2(length*(float) Math.Cos(Radians), -length*(float) Math.Sin(Radians));
        }

        public static bool IsBetween(Angle value, Angle min, Angle end)
        {
            return end < min
                ? (value >= min) || (value <= end)
                : (value >= min) && (value <= end);
        }

        public int CompareTo(Angle other)
        {
            WrapPositive();
            other.WrapPositive();
            return Radians.CompareTo(other.Radians);
        }

        public bool Equals(Angle other)
        {
            WrapPositive();
            other.WrapPositive();
            return Radians.Equals(other.Radians);
        }

        public override bool Equals(object obj)
        {
            if (ReferenceEquals(null, obj)) return false;
            return obj is Angle a && Equals(a);
        }

        public override int GetHashCode()
        {
            // ReSharper disable once NonReadonlyMemberInGetHashCode
            return Radians.GetHashCode();
        }

        public static implicit operator float(Angle angle)
        {
            return angle.Radians;
        }

        public static explicit operator Angle(float angle)
        {
            return new Angle(angle);
        }

        public static Angle operator -(Angle angle)
        {
            return new Angle(-angle.Radians);
        }

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

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

        public static Angle operator -(Angle left, Angle right)
        {
            return new Angle(left.Radians - right.Radians);
        }

        public static Angle operator *(Angle left, float right)
        {
            return new Angle(left.Radians*right);
        }

        public static Angle operator *(float left, Angle right)
        {
            return new Angle(right.Radians*left);
        }

        public static Angle operator +(Angle left, Angle right)
        {
            return new Angle(left.Radians + right.Radians);
        }

        public override string ToString()
        {
            return $"{Radians} Radians";
        }
    }
}