blender/intern/cycles/util/util_hash.h
Brecht Van Lommel c3e1fce775 Cycles: add Object Info node, with outputs object location, object/material
pass index, and a random number unique to the instance of the object.

This can be useful to give some variation to a single material assigned to
multiple instances, either manually controlled through the object index, based
on the object location, or randomized for each instance. 

http://wiki.blender.org/index.php/Doc:2.6/Manual/Render/Cycles/Nodes/More#Object_Info
2012-05-21 12:52:28 +00:00

68 lines
1.5 KiB
C

/*
* Copyright 2011, Blender Foundation.
*
* This program is free software; you can redistribute it and/or
* modify it under the terms of the GNU General Public License
* as published by the Free Software Foundation; either version 2
* of the License, or (at your option) any later version.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with this program; if not, write to the Free Software Foundation,
* Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
*/
#ifndef __UTIL_HASH_H__
#define __UTIL_HASH_H__
#include "util_types.h"
CCL_NAMESPACE_BEGIN
static inline uint hash_int_2d(uint kx, uint ky)
{
#define rot(x,k) (((x)<<(k)) | ((x)>>(32-(k))))
uint a, b, c;
a = b = c = 0xdeadbeef + (2 << 2) + 13;
a += kx;
b += ky;
c ^= b; c -= rot(b,14);
a ^= c; a -= rot(c,11);
b ^= a; b -= rot(a,25);
c ^= b; c -= rot(b,16);
a ^= c; a -= rot(c,4);
b ^= a; b -= rot(a,14);
c ^= b; c -= rot(b,24);
return c;
#undef rot
}
static inline uint hash_int(uint k)
{
return hash_int_2d(k, 0);
}
static inline uint hash_string(const char *str)
{
uint i = 0, c;
while ((c = *str++))
i = i * 37 + c;
return i;
}
CCL_NAMESPACE_END
#endif /* __UTIL_HASH_H__ */