| 5 |
|
* Anticorrelated random function due to Christophe Schlick |
| 6 |
|
*/ |
| 7 |
|
|
| 8 |
< |
/* ==================================================================== |
| 9 |
< |
* The Radiance Software License, Version 1.0 |
| 10 |
< |
* |
| 11 |
< |
* Copyright (c) 1990 - 2002 The Regents of the University of California, |
| 12 |
< |
* through Lawrence Berkeley National Laboratory. All rights reserved. |
| 13 |
< |
* |
| 14 |
< |
* Redistribution and use in source and binary forms, with or without |
| 15 |
< |
* modification, are permitted provided that the following conditions |
| 16 |
< |
* are met: |
| 17 |
< |
* |
| 18 |
< |
* 1. Redistributions of source code must retain the above copyright |
| 19 |
< |
* notice, this list of conditions and the following disclaimer. |
| 20 |
< |
* |
| 21 |
< |
* 2. Redistributions in binary form must reproduce the above copyright |
| 22 |
< |
* notice, this list of conditions and the following disclaimer in |
| 23 |
< |
* the documentation and/or other materials provided with the |
| 24 |
< |
* distribution. |
| 25 |
< |
* |
| 26 |
< |
* 3. The end-user documentation included with the redistribution, |
| 27 |
< |
* if any, must include the following acknowledgment: |
| 28 |
< |
* "This product includes Radiance software |
| 29 |
< |
* (http://radsite.lbl.gov/) |
| 30 |
< |
* developed by the Lawrence Berkeley National Laboratory |
| 31 |
< |
* (http://www.lbl.gov/)." |
| 32 |
< |
* Alternately, this acknowledgment may appear in the software itself, |
| 33 |
< |
* if and wherever such third-party acknowledgments normally appear. |
| 34 |
< |
* |
| 35 |
< |
* 4. The names "Radiance," "Lawrence Berkeley National Laboratory" |
| 36 |
< |
* and "The Regents of the University of California" must |
| 37 |
< |
* not be used to endorse or promote products derived from this |
| 38 |
< |
* software without prior written permission. For written |
| 39 |
< |
* permission, please contact [email protected]. |
| 40 |
< |
* |
| 41 |
< |
* 5. Products derived from this software may not be called "Radiance", |
| 42 |
< |
* nor may "Radiance" appear in their name, without prior written |
| 43 |
< |
* permission of Lawrence Berkeley National Laboratory. |
| 44 |
< |
* |
| 45 |
< |
* THIS SOFTWARE IS PROVIDED ``AS IS'' AND ANY EXPRESSED OR IMPLIED |
| 46 |
< |
* 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 |
< |
* SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT |
| 51 |
< |
* LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF |
| 52 |
< |
* USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND |
| 53 |
< |
* ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, |
| 54 |
< |
* 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 |
| 56 |
< |
* SUCH DAMAGE. |
| 57 |
< |
* ==================================================================== |
| 58 |
< |
* |
| 59 |
< |
* This software consists of voluntary contributions made by many |
| 60 |
< |
* individuals on behalf of Lawrence Berkeley National Laboratory. For more |
| 61 |
< |
* information on Lawrence Berkeley National Laboratory, please see |
| 62 |
< |
* <http://www.lbl.gov/>. |
| 63 |
< |
*/ |
| 8 |
> |
#include "copyright.h" |
| 9 |
|
|
| 10 |
|
#include <stdlib.h> |
| 11 |
+ |
|
| 12 |
+ |
#include "standard.h" |
| 13 |
|
#include "random.h" |
| 14 |
|
|
| 15 |
|
#undef initurand |
| 16 |
|
|
| 17 |
|
#define MAXORDER (8*sizeof(unsigned short)) |
| 18 |
|
|
| 19 |
< |
unsigned short *urperm = NULL; /* urand() permutation */ |
| 73 |
< |
int urmask; /* bits used in permutation */ |
| 19 |
> |
static unsigned short empty_tab = 0; |
| 20 |
|
|
| 21 |
+ |
unsigned short *urperm = &empty_tab; /* urand() permutation */ |
| 22 |
+ |
int urmask = 0; /* bits used in permutation */ |
| 23 |
+ |
|
| 24 |
|
int |
| 25 |
|
initurand(size) /* initialize urand() for size entries */ |
| 26 |
|
int size; |
| 28 |
|
int order, n; |
| 29 |
|
register int i, offset; |
| 30 |
|
|
| 31 |
< |
if (urperm != NULL) |
| 31 |
> |
if ((urperm != NULL) & (urperm != &empty_tab)) |
| 32 |
|
free((void *)urperm); |
| 33 |
|
if (--size <= 0) { |
| 34 |
< |
urperm = NULL; |
| 34 |
> |
empty_tab = 0; |
| 35 |
> |
urperm = &empty_tab; |
| 36 |
|
urmask = 0; |
| 37 |
|
return(0); |
| 38 |
|
} |
| 39 |
< |
for (i = 1; size >>= 1; i++) |
| 40 |
< |
; |
| 41 |
< |
order = i>MAXORDER ? MAXORDER : i; |
| 42 |
< |
urmask = (1<<i) - 1; |
| 39 |
> |
for (i = 1; (size >>= 1); i++) |
| 40 |
> |
if (i == MAXORDER) |
| 41 |
> |
break; |
| 42 |
> |
order = i; |
| 43 |
> |
urmask = (1<<order) - 1; |
| 44 |
|
urperm = (unsigned short *)malloc((urmask+1)*sizeof(unsigned short)); |
| 45 |
|
if (urperm == NULL) { |
| 46 |
|
eputs("out of memory in initurand\n"); |
| 49 |
|
urperm[0] = 0; |
| 50 |
|
for (n = 1, offset = 1; n <= order; n++, offset <<= 1) |
| 51 |
|
for (i = offset; i--; ) { |
| 52 |
< |
urperm[i] = |
| 102 |
< |
urperm[i+offset] = 2*urperm[i]; |
| 52 |
> |
urperm[i+offset] = urperm[i] <<= 1; |
| 53 |
|
if (random() & 0x4000) |
| 54 |
|
urperm[i]++; |
| 55 |
|
else |
| 56 |
|
urperm[i+offset]++; |
| 57 |
|
} |
| 58 |
< |
return(1<<order); |
| 58 |
> |
return(urmask+1); |
| 59 |
|
} |
| 60 |
|
|
| 61 |
|
|
| 64 |
|
register int *d; |
| 65 |
|
register int n; |
| 66 |
|
{ |
| 67 |
< |
static int tab[8] = {13623,353,1637,5831,2314,3887,5832,8737}; |
| 67 |
> |
static int tab[8] = {103699,96289,73771,65203,81119,87037,92051,98899}; |
| 68 |
|
register int hval; |
| 69 |
|
|
| 70 |
|
hval = 0; |
| 71 |
|
while (n-- > 0) |
| 72 |
< |
hval += *d++ * tab[n&7]; |
| 73 |
< |
return(hval); |
| 72 |
> |
hval ^= *d++ * tab[n&7]; |
| 73 |
> |
return(hval & 0x7fffffff); |
| 74 |
|
} |
