120 lines
3.4 KiB
C#
120 lines
3.4 KiB
C#
using System;
|
|
|
|
// Sci-Fi Ship Controller. Copyright (c) 2018-2023 SCSM Pty Ltd. All rights reserved.
|
|
namespace SciFiShipController
|
|
{
|
|
/// <summary>
|
|
/// SSCRandom is a linear congruential generator.
|
|
/// It is a renamed version of LBRandom from Landscape Builder
|
|
/// Usage:
|
|
/// SSCRandom sscRandom = new SSCRandom();
|
|
/// // Set a seed value
|
|
/// if (sscRandom != null)
|
|
/// {
|
|
/// sscRandom.SetSeed(85.3f);
|
|
/// float randomNumber1 = sscRandom.Next();
|
|
/// float randomNumber2 = sscRandom.Next();
|
|
/// s3dRandom = null;
|
|
/// }
|
|
/// </summary>
|
|
public class SSCRandom
|
|
{
|
|
#region Public variables and properties
|
|
|
|
/// <summary>
|
|
/// Returns the last generated random number.
|
|
/// NOTE: This is NOT the values returned by the Range() methods
|
|
/// </summary>
|
|
public UInt32 GetLast { get { return currentInt; } }
|
|
|
|
#endregion
|
|
|
|
#region Private variables
|
|
private UInt32 currentInt;
|
|
|
|
#endregion
|
|
|
|
#region Constructors
|
|
|
|
public SSCRandom()
|
|
{
|
|
SetClassDefaults();
|
|
}
|
|
|
|
#endregion
|
|
|
|
#region Public Non-Static Methods
|
|
|
|
public void SetSeed(int seed)
|
|
{
|
|
// Must be > 0
|
|
seed = seed < 0 ? -seed : (seed == 0 ? 1 : seed);
|
|
|
|
currentInt = (UInt32)(((UInt64)seed * 279470273uL) % (UInt64)0xfffffffb);
|
|
}
|
|
|
|
public UInt32 Next()
|
|
{
|
|
currentInt = (UInt32)(((UInt64)currentInt * 279470273uL) % (UInt64)0xfffffffb);
|
|
|
|
return currentInt;
|
|
}
|
|
|
|
/// <summary>
|
|
/// Return values between min (inclusive) and max (exclusive)
|
|
/// </summary>
|
|
/// <param name="min"></param>
|
|
/// <param name="max"></param>
|
|
/// <returns></returns>
|
|
public float Range(float min, float max)
|
|
{
|
|
// Get a value between 0.0 and 0.999.
|
|
// NOTE: We don't actually ever want 1.0f returned
|
|
float nF = Normalised();
|
|
|
|
return ((max - min) * nF) + min;
|
|
}
|
|
|
|
/// <summary>
|
|
/// Return values between min (inclusive) and max (inclusive)
|
|
/// </summary>
|
|
/// <param name="min"></param>
|
|
/// <param name="max"></param>
|
|
/// <returns></returns>
|
|
public int Range(int min, int max)
|
|
{
|
|
// Get a value between 0.0 and 0.999.
|
|
// NOTE: We don't actually ever want 1.0f returned
|
|
float nF = Normalised();
|
|
|
|
// Expand min/max range by subtracting 0.5 from min, and adding 0.5 to max.
|
|
// This will ensure the min and max values have the same distribution as
|
|
// values between min and max.
|
|
// Fast round by adding 0.5 and casting to int - similar to Math.Floor()
|
|
return (int)((float)(((max - min + 1) * nF) + min - 0.5f) + 0.5f);
|
|
}
|
|
|
|
/// <summary>
|
|
/// Return a value between 0.000 (inclusive) and 1.000 (exclusive)
|
|
/// i.e. max value will be 0.999.
|
|
/// </summary>
|
|
/// <returns></returns>
|
|
public float Normalised()
|
|
{
|
|
currentInt = Next();
|
|
|
|
return (float)(currentInt % 1000) / 1000f;
|
|
}
|
|
|
|
#endregion
|
|
|
|
#region Private Non-static Methods
|
|
|
|
private void SetClassDefaults()
|
|
{
|
|
currentInt = 0u;
|
|
}
|
|
|
|
#endregion
|
|
}
|
|
} |