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|
* Anticorrelated random function due to Christophe Schlick |
6 |
|
*/ |
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|
|
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< |
/* ==================================================================== |
9 |
< |
* The Radiance Software License, Version 1.0 |
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* |
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* Copyright (c) 1990 - 2002 The Regents of the University of California, |
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* through Lawrence Berkeley National Laboratory. All rights reserved. |
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* |
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* Redistribution and use in source and binary forms, with or without |
15 |
< |
* modification, are permitted provided that the following conditions |
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< |
* are met: |
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< |
* |
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* 1. Redistributions of source code must retain the above copyright |
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* notice, this list of conditions and the following disclaimer. |
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* |
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* 2. Redistributions in binary form must reproduce the above copyright |
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< |
* notice, this list of conditions and the following disclaimer in |
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< |
* the documentation and/or other materials provided with the |
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< |
* distribution. |
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* |
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* 3. The end-user documentation included with the redistribution, |
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* if any, must include the following acknowledgment: |
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* "This product includes Radiance software |
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* (http://radsite.lbl.gov/) |
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* developed by the Lawrence Berkeley National Laboratory |
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* (http://www.lbl.gov/)." |
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* Alternately, this acknowledgment may appear in the software itself, |
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< |
* if and wherever such third-party acknowledgments normally appear. |
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* |
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* 4. The names "Radiance," "Lawrence Berkeley National Laboratory" |
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< |
* and "The Regents of the University of California" must |
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< |
* not be used to endorse or promote products derived from this |
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< |
* software without prior written permission. For written |
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< |
* permission, please contact [email protected]. |
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* |
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* 5. Products derived from this software may not be called "Radiance", |
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< |
* nor may "Radiance" appear in their name, without prior written |
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< |
* permission of Lawrence Berkeley National Laboratory. |
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* |
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* THIS SOFTWARE IS PROVIDED ``AS IS'' AND ANY EXPRESSED OR IMPLIED |
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< |
* WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES |
47 |
< |
* OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE |
48 |
< |
* DISCLAIMED. IN NO EVENT SHALL Lawrence Berkeley National Laboratory OR |
49 |
< |
* ITS CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, |
50 |
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* SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT |
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< |
* LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF |
52 |
< |
* USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND |
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< |
* ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, |
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< |
* OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT |
55 |
< |
* OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF |
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< |
* SUCH DAMAGE. |
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* ==================================================================== |
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* |
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< |
* This software consists of voluntary contributions made by many |
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< |
* individuals on behalf of Lawrence Berkeley National Laboratory. For more |
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< |
* information on Lawrence Berkeley National Laboratory, please see |
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< |
* <http://www.lbl.gov/>. |
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< |
*/ |
8 |
> |
#include "copyright.h" |
9 |
|
|
10 |
< |
#include <stdlib.h> |
10 |
> |
#include "rterror.h" |
11 |
|
#include "random.h" |
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|
|
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|
#undef initurand |
14 |
|
|
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|
#define MAXORDER (8*sizeof(unsigned short)) |
16 |
|
|
17 |
< |
unsigned short *urperm = NULL; /* urand() permutation */ |
73 |
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int urmask; /* bits used in permutation */ |
17 |
> |
static unsigned short empty_tab = 0; |
18 |
|
|
19 |
+ |
unsigned short *urperm = &empty_tab; /* urand() permutation */ |
20 |
+ |
int urmask = 0; /* bits used in permutation */ |
21 |
+ |
|
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+ |
|
23 |
+ |
long |
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+ |
irandom( /* better than using random() % modulus */ |
25 |
+ |
long modulus |
26 |
+ |
) |
27 |
+ |
{ |
28 |
+ |
if (sizeof(long) >= 8) |
29 |
+ |
return((random()*modulus)>>31); |
30 |
+ |
|
31 |
+ |
if (sizeof(long long) >= 8) |
32 |
+ |
return((random()*(long long)modulus)>>31); |
33 |
+ |
|
34 |
+ |
return(frandom()*modulus); |
35 |
+ |
} |
36 |
+ |
|
37 |
|
int |
38 |
< |
initurand(size) /* initialize urand() for size entries */ |
39 |
< |
int size; |
38 |
> |
initurand( /* initialize urand() for size entries */ |
39 |
> |
int size |
40 |
> |
) |
41 |
|
{ |
42 |
|
int order, n; |
43 |
< |
register int i, offset; |
43 |
> |
int i, offset; |
44 |
|
|
45 |
< |
if (urperm != NULL) |
45 |
> |
if ((urperm != NULL) & (urperm != &empty_tab)) |
46 |
|
free((void *)urperm); |
47 |
|
if (--size <= 0) { |
48 |
< |
urperm = NULL; |
48 |
> |
empty_tab = 0; |
49 |
> |
urperm = &empty_tab; |
50 |
|
urmask = 0; |
51 |
|
return(0); |
52 |
|
} |
53 |
< |
for (i = 1; size >>= 1; i++) |
54 |
< |
; |
55 |
< |
order = i>MAXORDER ? MAXORDER : i; |
56 |
< |
urmask = (1<<i) - 1; |
53 |
> |
for (i = 1; (size >>= 1); i++) |
54 |
> |
if (i == MAXORDER) |
55 |
> |
break; |
56 |
> |
order = i; |
57 |
> |
urmask = (1<<order) - 1; |
58 |
|
urperm = (unsigned short *)malloc((urmask+1)*sizeof(unsigned short)); |
59 |
|
if (urperm == NULL) { |
60 |
|
eputs("out of memory in initurand\n"); |
63 |
|
urperm[0] = 0; |
64 |
|
for (n = 1, offset = 1; n <= order; n++, offset <<= 1) |
65 |
|
for (i = offset; i--; ) { |
66 |
< |
urperm[i] = |
102 |
< |
urperm[i+offset] = 2*urperm[i]; |
66 |
> |
urperm[i+offset] = urperm[i] <<= 1; |
67 |
|
if (random() & 0x4000) |
68 |
|
urperm[i]++; |
69 |
|
else |
70 |
|
urperm[i+offset]++; |
71 |
|
} |
72 |
< |
return(1<<order); |
72 |
> |
return(urmask+1); |
73 |
|
} |
74 |
|
|
75 |
|
|
76 |
|
int |
77 |
< |
ilhash(d, n) /* hash a set of integer values */ |
78 |
< |
register int *d; |
79 |
< |
register int n; |
77 |
> |
ilhash( /* hash a set of integer values */ |
78 |
> |
int *d, |
79 |
> |
int n |
80 |
> |
) |
81 |
|
{ |
82 |
< |
static int tab[8] = {13623,353,1637,5831,2314,3887,5832,8737}; |
83 |
< |
register int hval; |
82 |
> |
static int tab[8] = {103699,96289,73771,65203,81119,87037,92051,98899}; |
83 |
> |
int hval; |
84 |
|
|
85 |
|
hval = 0; |
86 |
|
while (n-- > 0) |
87 |
< |
hval += *d++ * tab[n&7]; |
88 |
< |
return(hval); |
87 |
> |
hval ^= *d++ * tab[n&7]; |
88 |
> |
return(hval & 0x7fffffff); |
89 |
|
} |