-
Notifications
You must be signed in to change notification settings - Fork 5
/
Copy pathtwister.cpp
93 lines (84 loc) · 2.57 KB
/
twister.cpp
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
#include<math.h>
#include<stdlib.h>
#include"twister.h"
namespace RayTracer {
unsigned short mtRand_xsubi[3] = { 723, 32761, 44444 };
#define M 397
#define MATRIX_A 0x9908b0df
#define UPPER_MASK 0x80000000
#define LOWER_MASK 0x7fffffff
#define TEMPERING_MASK_B 0x9d2c5680
#define TEMPERING_MASK_C 0xefc60000
#define TEMPERING_SHIFT_U(y) (y >> 11)
#define TEMPERING_SHIFT_S(y) (y << 7)
#define TEMPERING_SHIFT_T(y) (y << 15)
#define TEMPERING_SHIFT_L(y) (y >> 18)
void Twister::Seed( unsigned long seed )
{
mt[0]= seed & 0xffffffff;
for ( mti = 1; mti < mtRand_N; mti++ ) mt[mti] = (69069 * mt[mti - 1]) & 0xffffffff;
unsigned long s = 373737;
for ( mti = 1; mti < mtRand_N; mti++ )
{
mt[mti] ^= s;
s = s * 5531 + 81547;
s ^= (s >> 9) ^ (s << 19);
}
}
float Twister::Rand()
{
unsigned long y;
static unsigned long mag01[2] = {0x0, MATRIX_A};
if (mti >= mtRand_N)
{
int kk;
for (kk=0;kk<mtRand_N-M;kk++)
{
y = (mt[kk]&UPPER_MASK)|(mt[kk+1]&LOWER_MASK);
mt[kk] = mt[kk+M] ^ (y >> 1) ^ mag01[y & 0x1];
}
for (;kk<mtRand_N-1;kk++)
{
y = (mt[kk]&UPPER_MASK)|(mt[kk+1]&LOWER_MASK);
mt[kk] = mt[kk+(M-mtRand_N)] ^ (y >> 1) ^ mag01[y & 0x1];
}
y = (mt[mtRand_N-1]&UPPER_MASK)|(mt[0]&LOWER_MASK);
mt[mtRand_N-1] = mt[M-1] ^ (y >> 1) ^ mag01[y & 0x1];
mti = 0;
}
y = mt[mti++];
y ^= TEMPERING_SHIFT_U(y);
y ^= TEMPERING_SHIFT_S(y) & TEMPERING_MASK_B;
y ^= TEMPERING_SHIFT_T(y) & TEMPERING_MASK_C;
y ^= TEMPERING_SHIFT_L(y);
return ( (float)y * 2.3283064370807974e-10f );
}
unsigned long Twister::RandL()
{
unsigned long y;
static unsigned long mag01[2] = { 0x0, MATRIX_A };
if (mti >= mtRand_N)
{
int kk;
for (kk=0;kk<mtRand_N-M;kk++)
{
y = (mt[kk]&UPPER_MASK)|(mt[kk+1]&LOWER_MASK);
mt[kk] = mt[kk+M] ^ (y >> 1) ^ mag01[y & 0x1];
}
for (;kk<mtRand_N-1;kk++)
{
y = (mt[kk]&UPPER_MASK)|(mt[kk+1]&LOWER_MASK);
mt[kk] = mt[kk+(M-mtRand_N)] ^ (y >> 1) ^ mag01[y & 0x1];
}
y = (mt[mtRand_N-1]&UPPER_MASK)|(mt[0]&LOWER_MASK);
mt[mtRand_N-1] = mt[M-1] ^ (y >> 1) ^ mag01[y & 0x1];
mti = 0;
}
y = mt[mti++];
y ^= TEMPERING_SHIFT_U(y);
y ^= TEMPERING_SHIFT_S(y) & TEMPERING_MASK_B;
y ^= TEMPERING_SHIFT_T(y) & TEMPERING_MASK_C;
y ^= TEMPERING_SHIFT_L(y);
return y;
}
}; // namespace RayTracer