#region License Information (GPL v3)
/*
ShareX - A program that allows you to take screenshots and share any file type
Copyright (c) 2007-2018 ShareX Team
This program is free software; you can redistribute it and/or
modify it under the terms of the GNU General Public License
as published by the Free Software Foundation; either version 2
of the License, or (at your option) any later version.
This program is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
GNU General Public License for more details.
You should have received a copy of the GNU General Public License
along with this program; if not, write to the Free Software
Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
Optionally you can also view the license at .
*/
#endregion License Information (GPL v3)
using System;
using System.Security.Cryptography;
namespace ShareX.HelpersLib
{
public static class MathHelpers
{
public const float RadianPI = 57.29578f; // 180.0 / Math.PI
public const float DegreePI = 0.01745329f; // Math.PI / 180.0
public const float TwoPI = 6.28319f; // Math.PI * 2
private static readonly object randomLock = new object();
private static readonly Random random = new Random();
private static readonly object cryptoRandomLock = new object();
private static readonly RNGCryptoServiceProvider cryptoRandom = new RNGCryptoServiceProvider();
private static byte[] rngBuf = new byte[4];
///
/// Returns a random number between 0 and max (inclusive).
///
///
/// This uses System.Random(), which does not provide safe random numbers. This function
/// should not be used to generate things that should be unique, like random file names.
///
/// The upper limit of the number (inclusive).
/// A random number.
public static int Random(int max)
{
lock (randomLock)
{
return random.Next(max + 1);
}
}
public static int Random(int min, int max)
{
lock (randomLock)
{
return random.Next(min, max + 1);
}
}
///
/// Returns a random number between 0 and max (inclusive) generated with a cryptographic PRNG.
///
/// The upper limit of the number (inclusive).
/// A cryptographically random number.
public static int CryptoRandom(int max)
{
return CryptoRandom(0, max);
}
///
/// Returns a random number between min and max (inclusive) generated with a cryptographic PRNG.
///
/// The lower limit of the number.
/// The upper limit of the number (inclusive).
/// A cryptographically random number.
public static int CryptoRandom(int min, int max)
{
// this code avoids bias in random number generation, which is important when generating random filenames, etc.
// adapted from https://web.archive.org/web/20150114085328/http://msdn.microsoft.com:80/en-us/magazine/cc163367.aspx
if (min > max)
{
throw new ArgumentOutOfRangeException("min");
}
if (min == max)
{
return min;
}
lock (cryptoRandomLock)
{
long diff = (long)max - min;
long ceiling = 1 + (long)uint.MaxValue;
long remainder = ceiling % diff;
// this should only iterate once unless we generate really large numbers
uint r;
do
{
cryptoRandom.GetBytes(rngBuf);
r = BitConverter.ToUInt32(rngBuf, 0);
} while (r >= ceiling - remainder);
return (int)(min + (r % diff));
}
}
public static float RadianToDegree(float radian)
{
return radian * RadianPI;
}
public static float DegreeToRadian(float degree)
{
return degree * DegreePI;
}
public static Vector2 RadianToVector2(float radian)
{
return new Vector2((float)Math.Cos(radian), (float)Math.Sin(radian));
}
public static Vector2 RadianToVector2(float radian, float length)
{
return RadianToVector2(radian) * length;
}
public static Vector2 DegreeToVector2(float degree)
{
return RadianToVector2(DegreeToRadian(degree));
}
public static Vector2 DegreeToVector2(float degree, float length)
{
return RadianToVector2(DegreeToRadian(degree), length);
}
public static float Vector2ToRadian(Vector2 direction)
{
return (float)Math.Atan2(direction.Y, direction.X);
}
public static float Vector2ToDegree(Vector2 direction)
{
return RadianToDegree(Vector2ToRadian(direction));
}
public static float LookAtRadian(Vector2 pos1, Vector2 pos2)
{
return (float)Math.Atan2(pos2.Y - pos1.Y, pos2.X - pos1.X);
}
public static Vector2 LookAtVector2(Vector2 pos1, Vector2 pos2)
{
return RadianToVector2(LookAtRadian(pos1, pos2));
}
public static float LookAtDegree(Vector2 pos1, Vector2 pos2)
{
return RadianToDegree(LookAtRadian(pos1, pos2));
}
public static float Distance(Vector2 pos1, Vector2 pos2)
{
return (float)Math.Sqrt(Math.Pow(pos2.X - pos1.X, 2) + Math.Pow(pos2.Y - pos1.Y, 2));
}
public static float Lerp(float value1, float value2, float amount)
{
return value1 + ((value2 - value1) * amount);
}
public static Vector2 Lerp(Vector2 pos1, Vector2 pos2, float amount)
{
float x = Lerp(pos1.X, pos2.X, amount);
float y = Lerp(pos1.Y, pos2.Y, amount);
return new Vector2(x, y);
}
public static void Clamp(ref T val, T min, T max) where T : IComparable
{
if (val.CompareTo(min) < 0)
{
val = min;
}
else if (val.CompareTo(max) > 0)
{
val = max;
}
}
public static T Clamp(T val, T min, T max) where T : IComparable
{
Clamp(ref val, min, max);
return val;
}
}
}