anx.framework/ANX.Framework/MathHelper.cs

#region Using Statements
using System;

#endregion // Using Statements

#region License

//
// This file is part of the ANX.Framework created by the "ANX.Framework developer group".
//
// This file is released under the Ms-PL license.
//
//
//
// Microsoft Public License (Ms-PL)
//
// This license governs use of the accompanying software. If you use the software, you accept this license. 
// If you do not accept the license, do not use the software.
//
// 1.Definitions
//   The terms "reproduce," "reproduction," "derivative works," and "distribution" have the same meaning 
//   here as under U.S. copyright law.
//   A "contribution" is the original software, or any additions or changes to the software.
//   A "contributor" is any person that distributes its contribution under this license.
//   "Licensed patents" are a contributor's patent claims that read directly on its contribution.
//
// 2.Grant of Rights
//   (A) Copyright Grant- Subject to the terms of this license, including the license conditions and limitations 
//       in section 3, each contributor grants you a non-exclusive, worldwide, royalty-free copyright license to 
//       reproduce its contribution, prepare derivative works of its contribution, and distribute its contribution
//       or any derivative works that you create.
//   (B) Patent Grant- Subject to the terms of this license, including the license conditions and limitations in 
//       section 3, each contributor grants you a non-exclusive, worldwide, royalty-free license under its licensed
//       patents to make, have made, use, sell, offer for sale, import, and/or otherwise dispose of its contribution 
//       in the software or derivative works of the contribution in the software.
//
// 3.Conditions and Limitations
//   (A) No Trademark License- This license does not grant you rights to use any contributors' name, logo, or trademarks.
//   (B) If you bring a patent claim against any contributor over patents that you claim are infringed by the software, your 
//       patent license from such contributor to the software ends automatically.
//   (C) If you distribute any portion of the software, you must retain all copyright, patent, trademark, and attribution 
//       notices that are present in the software.
//   (D) If you distribute any portion of the software in source code form, you may do so only under this license by including
//       a complete copy of this license with your distribution. If you distribute any portion of the software in compiled or 
//       object code form, you may only do so under a license that complies with this license.
//   (E) The software is licensed "as-is." You bear the risk of using it. The contributors give no express warranties, guarantees,
//       or conditions. You may have additional consumer rights under your local laws which this license cannot change. To the
//       extent permitted under your local laws, the contributors exclude the implied warranties of merchantability, fitness for a 
//       particular purpose and non-infringement.

#endregion // License

#region Based on work by the Mono.Xna Team
/*
MIT License
Copyright © 2006 The Mono.Xna Team

All rights reserved.

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.
*/
#endregion License

namespace ANX.Framework
{
    public static class MathHelper
    {
        public const float E = (float)Math.E;
        public const float Log10E = 0.4342945f;
        public const float Log2E = 1.442695f;
        public const float Pi = (float)Math.PI;
        public const float PiOver2 = (float)(Math.PI / 2.0);
        public const float PiOver4 = (float)(Math.PI / 4.0);
        public const float TwoPi = (float)(Math.PI * 2.0);

        public static float Barycentric(float value1, float value2, float value3, float amount1, float amount2)
        {
            return value1 + (value2 - value1) * amount1 + (value3 - value1) * amount2;
        }

        public static float CatmullRom(float value1, float value2, float value3, float value4, float amount)
        {
            // Using formula from http://www.mvps.org/directx/articles/catmull/
            // Internally using doubles not to lose precission
            double amountSquared = amount * amount;
            double amountCubed = amountSquared * amount;
            return (float)(0.5 * (2.0 * value2 +
                (value3 - value1) * amount +
                (2.0 * value1 - 5.0 * value2 + 4.0 * value3 - value4) * amountSquared +
                (3.0 * value2 - value1 - 3.0 * value3 + value4) * amountCubed));
        }

        public static float Clamp(float value, float min, float max)
        {
            // First we check to see if we're greater than the max
            value = (value > max) ? max : value;

            // Then we check to see if we're less than the min.
            value = (value < min) ? min : value;

            // There's no check to see if min > max.
            return value;
        }

        public static float Distance(float value1, float value2)
        {
            return Math.Abs(value1 - value2);
        }

        public static float Hermite(float value1, float tangent1, float value2, float tangent2, float amount)
        {
            // All transformed to double not to lose precission
            // Otherwise, for high numbers of param:amount the result is NaN instead of Infinity
            double v1 = value1, v2 = value2, t1 = tangent1, t2 = tangent2, s = amount, result;
            double sCubed = s * s * s;
            double sSquared = s * s;

            if (amount == 0f)
                result = value1;
            else if (amount == 1f)
                result = value2;
            else
                result = (2 * v1 - 2 * v2 + t2 + t1) * sCubed +
                    (3 * v2 - 3 * v1 - 2 * t1 - t2) * sSquared +
                    t1 * s +
                    v1;
            return (float)result;
        }


        public static float Lerp(float value1, float value2, float amount)
        {
            return value1 + (value2 - value1) * amount;
        }

        public static float Max(float value1, float value2)
        {
            return Math.Max(value1, value2);
        }

        public static float Min(float value1, float value2)
        {
            return Math.Min(value1, value2);
        }

        public static float SmoothStep(float value1, float value2, float amount)
        {
            // It is expected that 0 < amount < 1
            // If amount < 0, return value1
            // If amount > 1, return value2
            float result = MathHelper.Clamp(amount, 0f, 1f);
            result = MathHelper.Hermite(value1, 0f, value2, 0f, result);
            return result;
        }

        public static float ToDegrees(float radians)
        {
            // This method uses double precission internally,
            // though it returns single float
            // Factor = 180 / pi
            return (float)(radians * 57.295779513082320876798154814105);
        }

        public static float ToRadians(float degrees)
        {
            // This method uses double precission internally,
            // though it returns single float
            // Factor = pi / 180
            return (float)(degrees * 0.017453292519943295769236907684886);
        }


        public static float WrapAngle(float angle)
        {
            angle = (float)Math.IEEERemainder((double)angle, 6.2831854820251465); //2xPi precission is double
            if (angle <= -3.141593f)
            {
                angle += 6.283185f;
                return angle;
            }
            if (angle > 3.141593f)
            {
                angle -= 6.283185f;
            }
            return angle;
        }

    }
}