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
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
|
/*
* Copyright (C) Volition, Inc. 1999. All rights reserved.
*
* All source code herein is the property of Volition, Inc. You may not sell
* or otherwise commercially exploit the source or things you created based on the
* source.
*
*/
#include "math/staticrand.h"
#include "math/vecmat.h"
int Semirand_inited = 0;
int Semirand[SEMIRAND_MAX];
/**
* @brief Initialize Semirand array. Doesn't have to be called.
*/
void init_semirand()
{
int i;
Semirand_inited = 1;
for (i=0; i<SEMIRAND_MAX; i++)
Semirand[i] = (myrand() << 15) + myrand();
}
/**
* @brief Return a pseudo random 32 bit value given a reasonably small number.
*
* @param num Seed input number
* @return Pseudo random 32 bit value
*/
int static_rand(int num)
{
int a, b, c;
if (num < 0)
num *= -1;
if (!Semirand_inited)
init_semirand();
a = num & (SEMIRAND_MAX - 1);
b = (num >> SEMIRAND_MAX_LOG) & (SEMIRAND_MAX - 1);
c = (num >> (2 * SEMIRAND_MAX_LOG)) & (SEMIRAND_MAX - 1);
return Semirand[a] ^ Semirand[b] ^ Semirand[c];
}
/**
* @brief Return a random float in 0.0f .. 1.0f- (ie, it will never return 1.0f).
*
* @param num Seed input number
* @return Random value in 0.0f .. 1.0f- (ie, it will never return 1.0f).
*/
float static_randf(int num)
{
int a;
a = static_rand(num);
return (a & 0xffff) / 65536.0f;
}
/**
* @brief Return a random integer within a range. Note: min and max are inclusive
*
* @param num Seed input number
* @param min Minimum range integer to return
* @param max Maximum range integer to return
* @return Random integer within the range
*/
int static_rand_range(int num, int min, int max)
{
int rval = static_rand(num);
rval = (rval % (max - min + 1)) + min;
CLAMP(rval, min, max);
return rval;
}
/**
* @brief Return a random float within a range.
* Note: min and max are inclusive
*
* @param num Seed input number
* @param min Minimum range float to return
* @param max Maximum range float to return
* @return Random float within the range
*/
float static_randf_range(int num, float min, float max)
{
float rval;
rval = static_randf(num);
rval = rval * (max - min) + min;
return rval;
}
/**
* @brief [To be described]
*
* @param num Seed input number
* @param vp Vector
*/
void static_randvec(int num, vec3d *vp)
{
vp->xyz.x = static_randf(num) - 0.5f;
vp->xyz.y = static_randf(num+1) - 0.5f;
vp->xyz.z = static_randf(num+2) - 0.5f;
vm_vec_normalize_quick(vp);
}
/**
* @brief Randomly perturb a vector around a given (normalized vector) or optional orientation matrix.
*
* @param num
* @param out
* @param in
* @param max_angle
* @param orient
*/
void static_rand_cone(int num, vec3d *out, vec3d *in, float max_angle, matrix *orient)
{
vec3d t1, t2;
matrix *rot;
matrix m;
// get an orientation matrix
if(orient != NULL){
rot = orient;
} else {
vm_vector_2_matrix(&m, in, NULL, NULL);
rot = &m;
}
// axis 1
vm_rot_point_around_line(&t1, in, fl_radians(static_randf_range(num,-max_angle, max_angle)), &vmd_zero_vector, &rot->vec.fvec);
// axis 2
vm_rot_point_around_line(&t2, &t1, fl_radians(static_randf_range(num+1,-max_angle, max_angle)), &vmd_zero_vector, &rot->vec.rvec);
// axis 3
vm_rot_point_around_line(out, &t2, fl_radians(static_randf_range(num+2,-max_angle, max_angle)), &vmd_zero_vector, &rot->vec.uvec);
}
/////////////////////////////////////////////////////////////////////
// Alternate random number generator, that doesn't affect rand() sequence
/////////////////////////////////////////////////////////////////////
#define RND_MASK 0x6000
#define RND_MAX 0x7fff
int Rnd_seed = 1;
/**
* @brief Seed the alternative random number generator.
* Doesn't have to be called.
*
* @param seed Seed input number
*/
void init_static_rand_alt(int seed)
{
Rnd_seed = seed;
}
/**
* @brief Get a random integer between 1 and RND_MAX.
*
* @return Random integer between 1 and RND_MAX
*/
int static_rand_alt()
{
static int x=Rnd_seed;
int old_x;
old_x = x;
x >>= 1;
if ( old_x & 1 ) {
x ^= RND_MASK;
}
return x;
}
/**
* @brief Get a random integer between 0 and 1.0.
*
* @return Random float between 0 and 1.0
*/
float static_randf_alt()
{
int r = static_rand_alt();
return i2fl(r)/RND_MAX;
}
|
