046434e222
This allows us to get a hash for a set of state groups for a given pipeline. This can be used for example to get a hash of the fragment processing state of a pipeline so we can implement a cache for compiled arbfp/glsl programs.
99 lines
2.9 KiB
C
99 lines
2.9 KiB
C
/*
|
|
* Cogl
|
|
*
|
|
* An object oriented GL/GLES Abstraction/Utility Layer
|
|
*
|
|
* Copyright (C) 2007,2008,2009,2010 Intel Corporation.
|
|
*
|
|
* This library is free software; you can redistribute it and/or
|
|
* modify it under the terms of the GNU Lesser General Public
|
|
* License as published by the Free Software Foundation; either
|
|
* version 2 of the License, or (at your option) any later version.
|
|
*
|
|
* This library 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
|
|
* Lesser General Public License for more details.
|
|
*
|
|
* You should have received a copy of the GNU Lesser General Public
|
|
* License along with this library. If not, see <http://www.gnu.org/licenses/>.
|
|
*
|
|
*
|
|
*/
|
|
|
|
#ifndef __COGL_UTIL_H
|
|
#define __COGL_UTIL_H
|
|
|
|
#include <glib.h>
|
|
#include <math.h>
|
|
|
|
int
|
|
_cogl_util_next_p2 (int a);
|
|
|
|
/* The signbit macro is defined by ISO C99 so it should be available,
|
|
however if it's not we can fallback to an evil hack */
|
|
#ifdef signbit
|
|
#define cogl_util_float_signbit(x) signbit(x)
|
|
#else
|
|
/* This trick was stolen from here:
|
|
http://lists.boost.org/Archives/boost/2006/08/108731.php
|
|
|
|
It xors the integer reinterpretations of -1.0f and 1.0f. In theory
|
|
they should only differ by the signbit so that gives a mask for the
|
|
sign which we can just test against the value */
|
|
static inline gboolean
|
|
cogl_util_float_signbit (float x)
|
|
{
|
|
static const union { float f; guint32 i; } negative_one = { -1.0f };
|
|
static const union { float f; guint32 i; } positive_one = { +1.0f };
|
|
union { float f; guint32 i; } value = { x };
|
|
|
|
return !!((negative_one.i ^ positive_one.i) & value.i);
|
|
}
|
|
#endif
|
|
|
|
/* This is a replacement for the nearbyint function which always
|
|
rounds to the nearest integer. nearbyint is apparently a C99
|
|
function so it might not always be available but also it seems in
|
|
glibc it is defined as a function call so this macro could end up
|
|
faster anyway. We can't just add 0.5f because it will break for
|
|
negative numbers. */
|
|
#define COGL_UTIL_NEARBYINT(x) ((int) ((x) < 0.0f ? (x) - 0.5f : (x) + 0.5f))
|
|
|
|
/* Returns whether the given integer is a power of two */
|
|
static inline gboolean
|
|
_cogl_util_is_pot (unsigned int num)
|
|
{
|
|
/* Make sure there is only one bit set */
|
|
return (num & (num - 1)) == 0;
|
|
}
|
|
|
|
/* Split Bob Jenkins' One-at-a-Time hash
|
|
*
|
|
* This uses the One-at-a-Time hash algorithm designed by Bob Jenkins
|
|
* but the mixing step is split out so the function can be used in a
|
|
* more incremental fashion.
|
|
*/
|
|
static inline unsigned int
|
|
_cogl_util_one_at_a_time_hash (unsigned int hash,
|
|
void *key,
|
|
size_t bytes)
|
|
{
|
|
unsigned char *p = key;
|
|
int i;
|
|
|
|
for (i = 0; i < bytes; i++)
|
|
{
|
|
hash += p[i];
|
|
hash += (hash << 10);
|
|
hash ^= (hash >> 6);
|
|
}
|
|
|
|
return hash;
|
|
}
|
|
|
|
unsigned int
|
|
_cogl_util_one_at_a_time_mix (unsigned int hash);
|
|
|
|
#endif /* __COGL_UTIL_H */
|