fix not-even-vaguely-close random distribution

This commit is contained in:
Chris Forbes
2010-05-07 21:32:30 +12:00
parent 4de64ae5a8
commit 20aa3d6764
4 changed files with 20 additions and 19 deletions

View File

@@ -6,16 +6,16 @@ namespace OpenRA.Thirdparty
public class Random public class Random
{ {
int[] mt = new int[624]; uint[] mt = new uint[624];
int index = 0; int index = 0;
public Random() : this(Environment.TickCount) { } public Random() : this(Environment.TickCount) { }
public Random(int seed) public Random(int seed)
{ {
mt[0] = seed; mt[0] = (uint)seed;
for (var i = 1; i < mt.Length; i++) for (var i = 1u; i < mt.Length; i++)
mt[i] = 1812433253 * (mt[i - 1] ^ (mt[i - 1] >> 30)) + i; mt[i] = 1812433253u * (mt[i - 1] ^ (mt[i - 1] >> 30)) + i;
} }
public int Next() public int Next()
@@ -24,26 +24,29 @@ namespace OpenRA.Thirdparty
var y = mt[index]; var y = mt[index];
y ^= (y >> 11); y ^= (y >> 11);
y ^= (int)((y << 7) & 2636928640); y ^= ((y << 7) & 2636928640);
y ^= (int)((y << 15) & 4022730752); y ^= ((y << 15) & 4022730752);
y ^= y >> 18; y ^= y >> 18;
index = (index + 1) % 624; index = (index + 1) % 624;
return y; return (int)(y % int.MaxValue);
} }
public int Next(int low, int high) { return low + Next() % (high - low); } public int Next(int low, int high) { return low + Next() % (high - low); }
public int Next(int high) { return Next() % high; } public int Next(int high) { return Next() % high; }
public double NextDouble() { return (uint)Next() / (double)uint.MaxValue; } public double NextDouble() { return Math.Abs(Next() / (double)0x7fffffff); }
void Generate() void Generate()
{ {
for (var i = 0; i < mt.Length; i++) unchecked
{ {
var y = (mt[i] & int.MinValue) | (mt[(i + 1) % 624] & int.MaxValue); for (var i = 0u; i < mt.Length; i++)
mt[i] = mt[(i + 397) % 624] ^ (y >> 1); {
if ((y & 1) == 1) var y = (mt[i] & 0x80000000) | (mt[(i + 1) % 624] & 0x7fffffff);
mt[i] = (int)(mt[i] ^ 2567483615); mt[i] = mt[(i + 397u) % 624u] ^ (y >> 1);
if ((y & 1) == 1)
mt[i] = (mt[i] ^ 2567483615);
}
} }
} }
} }

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@@ -231,8 +231,8 @@ namespace OpenRA
public static float Gauss1D(this Thirdparty.Random r, int samples) public static float Gauss1D(this Thirdparty.Random r, int samples)
{ {
var xs = Graphics.Util.MakeArray(samples, _ => (float)r.NextDouble() * 2 - 1); return Graphics.Util.MakeArray(samples, _ => (float)r.NextDouble() * 2 - 1f)
return xs.Sum() / samples; .Sum() / samples;
} }
// Returns a random offset in the range [-1..1,-1..1] with a separable // Returns a random offset in the range [-1..1,-1..1] with a separable

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@@ -18,9 +18,8 @@
*/ */
#endregion #endregion
using OpenRA.Effects;
using OpenRA.Traits;
using OpenRA.Mods.RA; using OpenRA.Mods.RA;
using OpenRA.Traits;
namespace OpenRA.Mods.Aftermath namespace OpenRA.Mods.Aftermath
{ {

View File

@@ -20,10 +20,9 @@
using System.Collections.Generic; using System.Collections.Generic;
using System.Linq; using System.Linq;
using OpenRA.Effects; using OpenRA.GameRules;
using OpenRA.Traits; using OpenRA.Traits;
using OpenRA.Traits.Activities; using OpenRA.Traits.Activities;
using OpenRA.GameRules;
namespace OpenRA.Mods.RA namespace OpenRA.Mods.RA
{ {