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2a14e7c Sep 4, 2018
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using System;
using System.Runtime.CompilerServices;
using static Unity.Mathematics.math;
using System.Diagnostics;
namespace Unity.Mathematics
{
/// <summary>
/// Random Number Generator based on xorshift.
/// Designed for minimal state (32bits) to be easily embeddable into components.
/// Core functionality is integer multiplication free to improve vectorization
/// on less capable SIMD instruction sets.
/// </summary>
[Serializable]
public partial struct Random
{
public uint state;
/// <summary>
/// Constructs a Random instance with a given seed value. The seed must be non-zero.
/// </summary>
[MethodImpl(MethodImplOptions.AggressiveInlining)]
public Random(uint seed)
{
state = seed;
CheckInitState();
NextState();
}
/// <summary>
/// Initialized the state of the Random instance with a given seed value. The seed must be non-zero.
/// </summary>
[MethodImpl(MethodImplOptions.AggressiveInlining)]
public void InitState(uint seed = 0x6E624EB7u)
{
state = seed;
NextState();
}
/// <summary>Returns a uniformly random bool value.</summary>
[MethodImpl(MethodImplOptions.AggressiveInlining)]
public bool NextBool()
{
return (NextState() & 1) == 1;
}
/// <summary>Returns a uniformly random bool2 value.</summary>
[MethodImpl(MethodImplOptions.AggressiveInlining)]
public bool2 NextBool2()
{
uint v = NextState();
return (uint2(v) & uint2(1, 2)) == 0;
}
/// <summary>Returns a uniformly random bool3 value.</summary>
[MethodImpl(MethodImplOptions.AggressiveInlining)]
public bool3 NextBool3()
{
uint v = NextState();
return (uint3(v) & uint3(1, 2, 4)) == 0;
}
/// <summary>Returns a uniformly random bool4 value.</summary>
[MethodImpl(MethodImplOptions.AggressiveInlining)]
public bool4 NextBool4()
{
uint v = NextState();
return (uint4(v) & uint4(1, 2, 4, 8)) == 0;
}
/// <summary>Returns a uniformly random int value in the interval [-2147483647, 2147483647].</summary>
[MethodImpl(MethodImplOptions.AggressiveInlining)]
public int NextInt()
{
return (int)NextState() ^ -2147483648;
}
/// <summary>Returns a uniformly random int2 value with all components in the interval [-2147483647, 2147483647].</summary>
[MethodImpl(MethodImplOptions.AggressiveInlining)]
public int2 NextInt2()
{
return int2((int)NextState(), (int)NextState()) ^ -2147483648;
}
/// <summary>Returns a uniformly random int3 value with all components in the interval [-2147483647, 2147483647].</summary>
[MethodImpl(MethodImplOptions.AggressiveInlining)]
public int3 NextInt3()
{
return int3((int)NextState(), (int)NextState(), (int)NextState()) ^ -2147483648;
}
/// <summary>Returns a uniformly random int4 value with all components in the interval [-2147483647, 2147483647].</summary>
[MethodImpl(MethodImplOptions.AggressiveInlining)]
public int4 NextInt4()
{
return int4((int)NextState(), (int)NextState(), (int)NextState(), (int)NextState()) ^ -2147483648;
}
/// <summary>Returns a uniformly random int value in the interval [0, max).</summary>
[MethodImpl(MethodImplOptions.AggressiveInlining)]
public int NextInt(int max)
{
CheckNextIntMax(max);
return (int)((NextState() * (ulong)max) >> 32);
}
/// <summary>Returns a uniformly random int2 value with all components in the interval [0, max).</summary>
[MethodImpl(MethodImplOptions.AggressiveInlining)]
public int2 NextInt2(int2 max)
{
CheckNextIntMax(max.x);
CheckNextIntMax(max.y);
return int2((int)(NextState() * (ulong)max.x >> 32),
(int)(NextState() * (ulong)max.y >> 32));
}
/// <summary>Returns a uniformly random int3 value with all components in the interval [0, max).</summary>
[MethodImpl(MethodImplOptions.AggressiveInlining)]
public int3 NextInt3(int3 max)
{
CheckNextIntMax(max.x);
CheckNextIntMax(max.y);
CheckNextIntMax(max.z);
return int3((int)(NextState() * (ulong)max.x >> 32),
(int)(NextState() * (ulong)max.y >> 32),
(int)(NextState() * (ulong)max.z >> 32));
}
/// <summary>Returns a uniformly random int4 value with all components in the interval [0, max).</summary>
[MethodImpl(MethodImplOptions.AggressiveInlining)]
public int4 NextInt4(int4 max)
{
CheckNextIntMax(max.x);
CheckNextIntMax(max.y);
CheckNextIntMax(max.z);
CheckNextIntMax(max.w);
return int4((int)(NextState() * (ulong)max.x >> 32),
(int)(NextState() * (ulong)max.y >> 32),
(int)(NextState() * (ulong)max.z >> 32),
(int)(NextState() * (ulong)max.w >> 32));
}
/// <summary>Returns a uniformly random int value in the interval [min, max).</summary>
[MethodImpl(MethodImplOptions.AggressiveInlining)]
public int NextInt(int min, int max)
{
CheckNextIntMinMax(min, max);
uint range = (uint)(max - min);
return (int)(NextState() * (ulong)range >> 32) + min;
}
/// <summary>Returns a uniformly random int2 value with all components in the interval [min, max).</summary>
[MethodImpl(MethodImplOptions.AggressiveInlining)]
public int2 NextInt2(int2 min, int2 max)
{
CheckNextIntMinMax(min.x, max.x);
CheckNextIntMinMax(min.y, max.y);
uint2 range = (uint2)(max - min);
return int2((int)(NextState() * (ulong)range.x >> 32),
(int)(NextState() * (ulong)range.y >> 32)) + min;
}
/// <summary>Returns a uniformly random int3 value with all components in the interval [min, max).</summary>
[MethodImpl(MethodImplOptions.AggressiveInlining)]
public int3 NextInt3(int3 min, int3 max)
{
CheckNextIntMinMax(min.x, max.x);
CheckNextIntMinMax(min.y, max.y);
CheckNextIntMinMax(min.z, max.z);
uint3 range = (uint3)(max - min);
return int3((int)(NextState() * (ulong)range.x >> 32),
(int)(NextState() * (ulong)range.y >> 32),
(int)(NextState() * (ulong)range.z >> 32)) + min;
}
/// <summary>Returns a uniformly random int4 value with all components in the interval [min, max).</summary>
[MethodImpl(MethodImplOptions.AggressiveInlining)]
public int4 NextInt4(int4 min, int4 max)
{
CheckNextIntMinMax(min.x, max.x);
CheckNextIntMinMax(min.y, max.y);
CheckNextIntMinMax(min.z, max.z);
CheckNextIntMinMax(min.w, max.w);
uint4 range = (uint4)(max - min);
return int4((int)(NextState() * (ulong)range.x >> 32),
(int)(NextState() * (ulong)range.y >> 32),
(int)(NextState() * (ulong)range.z >> 32),
(int)(NextState() * (ulong)range.w >> 32)) + min;
}
/// <summary>Returns a uniformly random uint value in the interval [0, 4294967294].</summary>
[MethodImpl(MethodImplOptions.AggressiveInlining)]
public uint NextUInt()
{
return NextState() - 1u;
}
/// <summary>Returns a uniformly random uint2 value with all components in the interval [0, 4294967294].</summary>
[MethodImpl(MethodImplOptions.AggressiveInlining)]
public uint2 NextUInt2()
{
return uint2(NextState(), NextState()) - 1u;
}
/// <summary>Returns a uniformly random uint3 value with all components in the interval [0, 4294967294].</summary>
[MethodImpl(MethodImplOptions.AggressiveInlining)]
public uint3 NextUInt3()
{
return uint3(NextState(), NextState(), NextState()) - 1u;
}
/// <summary>Returns a uniformly random uint4 value with all components in the interval [0, 4294967294].</summary>
[MethodImpl(MethodImplOptions.AggressiveInlining)]
public uint4 NextUInt4()
{
return uint4(NextState(), NextState(), NextState(), NextState()) - 1u;
}
/// <summary>Returns a uniformly random uint value in the interval [0, max).</summary>
[MethodImpl(MethodImplOptions.AggressiveInlining)]
public uint NextUInt(uint max)
{
return (uint)((NextState() * (ulong)max) >> 32);
}
/// <summary>Returns a uniformly random uint2 value with all components in the interval [0, max).</summary>
[MethodImpl(MethodImplOptions.AggressiveInlining)]
public uint2 NextUInt2(uint2 max)
{
return uint2( (uint)(NextState() * (ulong)max.x >> 32),
(uint)(NextState() * (ulong)max.y >> 32));
}
/// <summary>Returns a uniformly random uint3 value with all components in the interval [0, max).</summary>
[MethodImpl(MethodImplOptions.AggressiveInlining)]
public uint3 NextUInt3(uint3 max)
{
return uint3( (uint)(NextState() * (ulong)max.x >> 32),
(uint)(NextState() * (ulong)max.y >> 32),
(uint)(NextState() * (ulong)max.z >> 32));
}
/// <summary>Returns a uniformly random uint4 value with all components in the interval [0, max).</summary>
[MethodImpl(MethodImplOptions.AggressiveInlining)]
public uint4 NextUInt4(uint4 max)
{
return uint4( (uint)(NextState() * (ulong)max.x >> 32),
(uint)(NextState() * (ulong)max.y >> 32),
(uint)(NextState() * (ulong)max.z >> 32),
(uint)(NextState() * (ulong)max.w >> 32));
}
/// <summary>Returns a uniformly random uint value in the interval [min, max).</summary>
[MethodImpl(MethodImplOptions.AggressiveInlining)]
public uint NextUInt(uint min, uint max)
{
CheckNextUIntMinMax(min, max);
uint range = max - min;
return (uint)(NextState() * (ulong)range >> 32) + min;
}
/// <summary>Returns a uniformly random uint2 value with all components in the interval [min, max).</summary>
[MethodImpl(MethodImplOptions.AggressiveInlining)]
public uint2 NextUInt2(uint2 min, uint2 max)
{
CheckNextUIntMinMax(min.x, max.x);
CheckNextUIntMinMax(min.y, max.y);
uint2 range = max - min;
return uint2((uint)(NextState() * (ulong)range.x >> 32),
(uint)(NextState() * (ulong)range.y >> 32)) + min;
}
/// <summary>Returns a uniformly random uint3 value with all components in the interval [min, max).</summary>
[MethodImpl(MethodImplOptions.AggressiveInlining)]
public uint3 NextUInt3(uint3 min, uint3 max)
{
CheckNextUIntMinMax(min.x, max.x);
CheckNextUIntMinMax(min.y, max.y);
CheckNextUIntMinMax(min.z, max.z);
uint3 range = max - min;
return uint3((uint)(NextState() * (ulong)range.x >> 32),
(uint)(NextState() * (ulong)range.y >> 32),
(uint)(NextState() * (ulong)range.z >> 32)) + min;
}
/// <summary>Returns a uniformly random uint4 value with all components in the interval [min, max).</summary>
[MethodImpl(MethodImplOptions.AggressiveInlining)]
public uint4 NextUInt4(uint4 min, uint4 max)
{
CheckNextUIntMinMax(min.x, max.x);
CheckNextUIntMinMax(min.y, max.y);
CheckNextUIntMinMax(min.z, max.z);
CheckNextUIntMinMax(min.w, max.w);
uint4 range = (uint4)(max - min);
return uint4((uint)(NextState() * (ulong)range.x >> 32),
(uint)(NextState() * (ulong)range.y >> 32),
(uint)(NextState() * (ulong)range.z >> 32),
(uint)(NextState() * (ulong)range.w >> 32)) + min;
}
/// <summary>Returns a uniformly random float value in the interval [0, 1).</summary>
[MethodImpl(MethodImplOptions.AggressiveInlining)]
public float NextFloat()
{
return asfloat(0x3f800000 | (NextState() >> 9)) - 1.0f;
}
/// <summary>Returns a uniformly random float2 value with all components in the interval [0, 1).</summary>
[MethodImpl(MethodImplOptions.AggressiveInlining)]
public float2 NextFloat2()
{
return asfloat(0x3f800000 | (uint2(NextState(), NextState()) >> 9)) - 1.0f;
}
/// <summary>Returns a uniformly random float3 value with all components in the interval [0, 1).</summary>
[MethodImpl(MethodImplOptions.AggressiveInlining)]
public float3 NextFloat3()
{
return asfloat(0x3f800000 | (uint3(NextState(), NextState(), NextState()) >> 9)) - 1.0f;
}
/// <summary>Returns a uniformly random float4 value with all components in the interval [0, 1).</summary>
[MethodImpl(MethodImplOptions.AggressiveInlining)]
public float4 NextFloat4()
{
return asfloat(0x3f800000 | (uint4(NextState(), NextState(), NextState(), NextState()) >> 9)) - 1.0f;
}
/// <summary>Returns a uniformly random float value in the interval [0, max).</summary>
[MethodImpl(MethodImplOptions.AggressiveInlining)]
public float NextFloat(float max) { return NextFloat() * max; }
/// <summary>Returns a uniformly random float2 value with all components in the interval [0, max).</summary>
[MethodImpl(MethodImplOptions.AggressiveInlining)]
public float2 NextFloat2(float2 max) { return NextFloat2() * max; }
/// <summary>Returns a uniformly random float3 value with all components in the interval [0, max).</summary>
[MethodImpl(MethodImplOptions.AggressiveInlining)]
public float3 NextFloat3(float3 max) { return NextFloat3() * max; }
/// <summary>Returns a uniformly random float4 value with all components in the interval [0, max).</summary>
[MethodImpl(MethodImplOptions.AggressiveInlining)]
public float4 NextFloat4(float4 max) { return NextFloat4() * max; }
/// <summary>Returns a uniformly random float value in the interval [min, max).</summary>
[MethodImpl(MethodImplOptions.AggressiveInlining)]
public float NextFloat(float min, float max) { return NextFloat() * (max - min) + min; }
/// <summary>Returns a uniformly random float2 value with all components in the interval [min, max).</summary>
[MethodImpl(MethodImplOptions.AggressiveInlining)]
public float2 NextFloat2(float2 min, float2 max) { return NextFloat2() * (max - min) + min; }
/// <summary>Returns a uniformly random float3 value with all components in the interval [min, max).</summary>
[MethodImpl(MethodImplOptions.AggressiveInlining)]
public float3 NextFloat3(float3 min, float3 max) { return NextFloat3() * (max - min) + min; }
/// <summary>Returns a uniformly random float4 value with all components in the interval [min, max).</summary>
[MethodImpl(MethodImplOptions.AggressiveInlining)]
public float4 NextFloat4(float4 min, float4 max) { return NextFloat4() * (max - min) + min; }
/// <summary>Returns a uniformly random double value in the interval [0, 1).</summary>
[MethodImpl(MethodImplOptions.AggressiveInlining)]
public double NextDouble()
{
ulong sx = ((ulong)NextState() << 20) ^ NextState();
return asdouble(0x3ff0000000000000 | sx) - 1.0;
}
/// <summary>Returns a uniformly random double2 value with all components in the interval [0, 1).</summary>
[MethodImpl(MethodImplOptions.AggressiveInlining)]
public double2 NextDouble2()
{
ulong sx = ((ulong)NextState() << 20) ^ NextState();
ulong sy = ((ulong)NextState() << 20) ^ NextState();
return double2(asdouble(0x3ff0000000000000 | sx),
asdouble(0x3ff0000000000000 | sy)) - 1.0;
}
/// <summary>Returns a uniformly random double3 value with all components in the interval [0, 1).</summary>
[MethodImpl(MethodImplOptions.AggressiveInlining)]
public double3 NextDouble3()
{
ulong sx = ((ulong)NextState() << 20) ^ NextState();
ulong sy = ((ulong)NextState() << 20) ^ NextState();
ulong sz = ((ulong)NextState() << 20) ^ NextState();
return double3(asdouble(0x3ff0000000000000 | sx),
asdouble(0x3ff0000000000000 | sy),
asdouble(0x3ff0000000000000 | sz)) - 1.0;
}
/// <summary>Returns a uniformly random double4 value with all components in the interval [0, 1).</summary>
[MethodImpl(MethodImplOptions.AggressiveInlining)]
public double4 NextDouble4()
{
ulong sx = ((ulong)NextState() << 20) ^ NextState();
ulong sy = ((ulong)NextState() << 20) ^ NextState();
ulong sz = ((ulong)NextState() << 20) ^ NextState();
ulong sw = ((ulong)NextState() << 20) ^ NextState();
return double4(asdouble(0x3ff0000000000000 | sx),
asdouble(0x3ff0000000000000 | sy),
asdouble(0x3ff0000000000000 | sz),
asdouble(0x3ff0000000000000 | sw)) - 1.0;
}
/// <summary>Returns a uniformly random double value in the interval [0, max).</summary>
[MethodImpl(MethodImplOptions.AggressiveInlining)]
public double NextDouble(double max) { return NextDouble() * max; }
/// <summary>Returns a uniformly random double2 value with all components in the interval [0, max).</summary>
[MethodImpl(MethodImplOptions.AggressiveInlining)]
public double2 NextDouble2(double2 max) { return NextDouble2() * max; }
/// <summary>Returns a uniformly random double3 value with all components in the interval [0, max).</summary>
[MethodImpl(MethodImplOptions.AggressiveInlining)]
public double3 NextDouble3(double3 max) { return NextDouble3() * max; }
/// <summary>Returns a uniformly random double4 value with all components in the interval [0, max).</summary>
[MethodImpl(MethodImplOptions.AggressiveInlining)]
public double4 NextDouble4(double4 max) { return NextDouble4() * max; }
/// <summary>Returns a uniformly random double value in the interval [min, max).</summary>
[MethodImpl(MethodImplOptions.AggressiveInlining)]
public double NextDouble(double min, double max) { return NextDouble() * (max - min) + min; }
/// <summary>Returns a uniformly random double2 value with all components in the interval [min, max).</summary>
[MethodImpl(MethodImplOptions.AggressiveInlining)]
public double2 NextDouble2(double2 min, double2 max) { return NextDouble2() * (max - min) + min; }
/// <summary>Returns a uniformly random double3 value with all components in the interval [min, max).</summary>
[MethodImpl(MethodImplOptions.AggressiveInlining)]
public double3 NextDouble3(double3 min, double3 max) { return NextDouble3() * (max - min) + min; }
/// <summary>Returns a uniformly random double4 value with all components in the interval [min, max).</summary>
[MethodImpl(MethodImplOptions.AggressiveInlining)]
public double4 NextDouble4(double4 min, double4 max) { return NextDouble4() * (max - min) + min; }
/// <summary>Returns a unit length float2 vector representing a uniformly random 2D direction.</summary>
[MethodImpl(MethodImplOptions.AggressiveInlining)]
public float2 NextFloat2Direction()
{
float angle = NextFloat() * (float)PI * 2.0f;
float s, c;
sincos(angle, out s, out c);
return float2(c, s);
}
/// <summary>Returns a unit length double2 vector representing a uniformly random 2D direction.</summary>
[MethodImpl(MethodImplOptions.AggressiveInlining)]
public double2 NextDouble2Direction()
{
double angle = NextDouble() * PI * 2.0;
double s, c;
sincos(angle, out s, out c);
return double2(c, s);
}
/// <summary>Returns a unit length float3 vector representing a uniformly random 3D direction.</summary>
[MethodImpl(MethodImplOptions.AggressiveInlining)]
public float3 NextFloat3Direction()
{
float2 rnd = NextFloat2();
float z = rnd.x * 2.0f - 1.0f;
float r = sqrt(max(1.0f - z * z, 0.0f));
float angle = rnd.y * (float)PI * 2.0f;
float s, c;
sincos(angle, out s, out c);
return float3(c*r, s*r, z);
}
/// <summary>Returns a unit length double3 vector representing a uniformly random 3D direction.</summary>
[MethodImpl(MethodImplOptions.AggressiveInlining)]
public double3 NextDouble3Direction()
{
double2 rnd = NextDouble2();
double z = rnd.x * 2.0 - 1.0;
double r = sqrt(max(1.0 - z * z, 0.0));
double angle = rnd.y * PI * 2.0;
double s, c;
sincos(angle, out s, out c);
return double3(c * r, s * r, z);
}
/// <summary>Returns a unit length quaternion representing a uniformly 3D rotation.</summary>
[MethodImpl(MethodImplOptions.AggressiveInlining)]
public quaternion NextQuaternionRotation()
{
float3 rnd = NextFloat3(float3(2.0f * (float)PI, 2.0f * (float)PI, 1.0f));
float u1 = rnd.z;
float2 theta_rho = rnd.xy;
float i = sqrt(1.0f - u1);
float j = sqrt(u1);
float2 sin_theta_rho;
float2 cos_theta_rho;
sincos(theta_rho, out sin_theta_rho, out cos_theta_rho);
quaternion q = quaternion(i * sin_theta_rho.x, i * cos_theta_rho.x, j * sin_theta_rho.y, j * cos_theta_rho.y);
return quaternion(select(q.value, -q.value, q.value.w < 0.0f));
}
[MethodImpl(MethodImplOptions.AggressiveInlining)]
private uint NextState()
{
CheckState();
uint t = state;
state ^= state << 13;
state ^= state >> 17;
state ^= state << 5;
return t;
}
[Conditional("ENABLE_UNITY_COLLECTIONS_CHECKS")]
private void CheckInitState()
{
#if ENABLE_UNITY_COLLECTIONS_CHECKS
if (state == 0)
throw new System.ArgumentException("Seed must be non-zero");
#endif
}
[Conditional("ENABLE_UNITY_COLLECTIONS_CHECKS")]
private void CheckState()
{
#if ENABLE_UNITY_COLLECTIONS_CHECKS
if(state == 0)
throw new System.ArgumentException("Invalid state 0. Random object has not been properly initialized");
#endif
}
[Conditional("ENABLE_UNITY_COLLECTIONS_CHECKS")]
private void CheckNextIntMax(int max)
{
#if ENABLE_UNITY_COLLECTIONS_CHECKS
if (max < 0)
throw new System.ArgumentException("max must be positive");
#endif
}
[Conditional("ENABLE_UNITY_COLLECTIONS_CHECKS")]
private void CheckNextIntMinMax(int min, int max)
{
#if ENABLE_UNITY_COLLECTIONS_CHECKS
if (min > max)
throw new System.ArgumentException("min must be less than or equal to max");
#endif
}
[Conditional("ENABLE_UNITY_COLLECTIONS_CHECKS")]
private void CheckNextUIntMinMax(uint min, uint max)
{
#if ENABLE_UNITY_COLLECTIONS_CHECKS
if (min > max)
throw new System.ArgumentException("min must be less than or equal to max");
#endif
}
}
}