mutter/cogl/cogl-util.c

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/*
* Cogl
*
* An object oriented GL/GLES Abstraction/Utility Layer
*
cogl: improves header and coding style consistency We've had complaints that our Cogl code/headers are a bit "special" so this is a first pass at tidying things up by giving them some consistency. These changes are all consistent with how new code in Cogl is being written, but the style isn't consistently applied across all code yet. There are two parts to this patch; but since each one required a large amount of effort to maintain tidy indenting it made sense to combine the changes to reduce the time spent re indenting the same lines. The first change is to use a consistent style for declaring function prototypes in headers. Cogl headers now consistently use this style for prototypes: return_type cogl_function_name (CoglType arg0, CoglType arg1); Not everyone likes this style, but it seems that most of the currently active Cogl developers agree on it. The second change is to constrain the use of redundant glib data types in Cogl. Uses of gint, guint, gfloat, glong, gulong and gchar have all been replaced with int, unsigned int, float, long, unsigned long and char respectively. When talking about pixel data; use of guchar has been replaced with guint8, otherwise unsigned char can be used. The glib types that we continue to use for portability are gboolean, gint{8,16,32,64}, guint{8,16,32,64} and gsize. The general intention is that Cogl should look palatable to the widest range of C programmers including those outside the Gnome community so - especially for the public API - we want to minimize the number of foreign looking typedefs.
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* 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/>.
*
*
*/
#ifdef HAVE_CONFIG_H
#include "config.h"
#endif
#include "cogl-util.h"
#include "cogl-private.h"
/*
* cogl_util_next_p2:
* @a: Value to get the next power of two
*
* Calculates the next power of two greater than or equal to @a.
*
* Return value: @a if @a is already a power of two, otherwise returns
* the next nearest power of two.
*/
int
_cogl_util_next_p2 (int a)
{
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int rval = 1;
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while (rval < a)
rval <<= 1;
return rval;
}
unsigned int
_cogl_util_one_at_a_time_mix (unsigned int hash)
{
hash += ( hash << 3 );
hash ^= ( hash >> 11 );
hash += ( hash << 15 );
return hash;
}
/* The 'ffs' function is part of C99 so it isn't always available */
#ifndef HAVE_FFS
int
_cogl_util_ffs (int num)
{
int i = 1;
if (num == 0)
return 0;
while ((num & 1) == 0)
{
num >>= 1;
i++;
}
return i;
}
#endif /* HAVE_FFS */
/* The 'ffsl' is non-standard but when building with GCC we'll use its
builtin instead */
#ifndef COGL_UTIL_HAVE_BUILTIN_FFSL
int
_cogl_util_ffsl_wrapper (long int num)
{
int i = 1;
if (num == 0)
return 0;
while ((num & 1) == 0)
{
num >>= 1;
i++;
}
return i;
}
#endif /* COGL_UTIL_HAVE_BUILTIN_FFSL */
#ifndef COGL_UTIL_HAVE_BUILTIN_POPCOUNTL
const unsigned char
_cogl_util_popcount_table[256] =
{
0, 1, 1, 2, 1, 2, 2, 3, 1, 2, 2, 3, 2, 3, 3, 4, 1, 2, 2, 3, 2, 3, 3, 4,
2, 3, 3, 4, 3, 4, 4, 5, 1, 2, 2, 3, 2, 3, 3, 4, 2, 3, 3, 4, 3, 4, 4, 5,
2, 3, 3, 4, 3, 4, 4, 5, 3, 4, 4, 5, 4, 5, 5, 6, 1, 2, 2, 3, 2, 3, 3, 4,
2, 3, 3, 4, 3, 4, 4, 5, 2, 3, 3, 4, 3, 4, 4, 5, 3, 4, 4, 5, 4, 5, 5, 6,
2, 3, 3, 4, 3, 4, 4, 5, 3, 4, 4, 5, 4, 5, 5, 6, 3, 4, 4, 5, 4, 5, 5, 6,
4, 5, 5, 6, 5, 6, 6, 7, 1, 2, 2, 3, 2, 3, 3, 4, 2, 3, 3, 4, 3, 4, 4, 5,
2, 3, 3, 4, 3, 4, 4, 5, 3, 4, 4, 5, 4, 5, 5, 6, 2, 3, 3, 4, 3, 4, 4, 5,
3, 4, 4, 5, 4, 5, 5, 6, 3, 4, 4, 5, 4, 5, 5, 6, 4, 5, 5, 6, 5, 6, 6, 7,
2, 3, 3, 4, 3, 4, 4, 5, 3, 4, 4, 5, 4, 5, 5, 6, 3, 4, 4, 5, 4, 5, 5, 6,
4, 5, 5, 6, 5, 6, 6, 7, 3, 4, 4, 5, 4, 5, 5, 6, 4, 5, 5, 6, 5, 6, 6, 7,
4, 5, 5, 6, 5, 6, 6, 7, 5, 6, 6, 7, 6, 7, 7, 8
};
#endif /* COGL_UTIL_HAVE_BUILTIN_POPCOUNTL */
/* tests/conform/test-bitmask.c tests some cogl internals and includes this
* file directly but since these functions depend on other internal Cogl
* symbols we hide them from test-bitmask.c
*
* XXX: maybe there's a better way for us to handle internal testing
* to avoid needing hacks like this.
*/
#ifndef _COGL_IN_TEST_BITMASK
/* Given a set of red, green and blue component masks, a depth and
* bits per pixel this function tries to determine a corresponding
* CoglPixelFormat.
*
* The depth is measured in bits not including padding for un-used
* alpha. The bits per pixel (bpp) does include padding for un-used
* alpha.
*
* This function firstly aims to match formats with RGB ordered
* components and only considers alpha coming first, in the most
* significant bits. If the function fails to match then it recurses
* by either switching the r and b masks around to check for BGR
* ordered formats or it recurses with the masks shifted to check for
* formats where the alpha component is the least significant bits.
*/
static CoglPixelFormat
_cogl_util_pixel_format_from_masks_real (unsigned long r_mask,
unsigned long g_mask,
unsigned long b_mask,
int depth, int bpp,
gboolean check_bgr,
gboolean check_afirst,
int recursion_depth)
{
CoglPixelFormat image_format;
if (depth == 24 && bpp == 24 &&
r_mask == 0xff0000 && g_mask == 0xff00 && b_mask == 0xff)
{
return COGL_PIXEL_FORMAT_RGB_888;
}
else if ((depth == 24 || depth == 32) && bpp == 32 &&
r_mask == 0xff0000 && g_mask == 0xff00 && b_mask == 0xff)
{
return COGL_PIXEL_FORMAT_ARGB_8888_PRE;
}
else if ((depth == 30 || depth == 32) &&
r_mask == 0x3ff00000 && g_mask == 0xffc00 && b_mask == 0x3ff)
{
return COGL_PIXEL_FORMAT_ARGB_2101010_PRE;
}
else if (depth == 16 && bpp == 16 &&
r_mask == 0xf800 && g_mask == 0x7e0 && b_mask == 0x1f)
{
return COGL_PIXEL_FORMAT_RGB_565;
}
if (recursion_depth == 2)
return 0;
/* Check for BGR ordering if we didn't find a match */
if (check_bgr)
{
image_format =
_cogl_util_pixel_format_from_masks_real (b_mask, g_mask, r_mask,
depth, bpp,
FALSE,
TRUE,
recursion_depth + 1);
if (image_format)
return image_format ^ COGL_BGR_BIT;
}
/* Check for alpha in the least significant bits if we still
* haven't found a match... */
if (check_afirst && depth != bpp)
{
int shift = bpp - depth;
image_format =
_cogl_util_pixel_format_from_masks_real (r_mask >> shift,
g_mask >> shift,
b_mask >> shift,
depth, bpp,
TRUE,
FALSE,
recursion_depth + 1);
if (image_format)
return image_format ^ COGL_AFIRST_BIT;
}
return 0;
}
CoglPixelFormat
_cogl_util_pixel_format_from_masks (unsigned long r_mask,
unsigned long g_mask,
unsigned long b_mask,
int depth, int bpp,
gboolean byte_order_is_lsb_first)
{
CoglPixelFormat image_format =
_cogl_util_pixel_format_from_masks_real (r_mask, g_mask, b_mask,
depth, bpp,
TRUE,
TRUE,
0);
if (!image_format)
{
const char *byte_order[] = { "MSB first", "LSB first" };
g_warning ("Could not find a matching pixel format for red mask=0x%lx,"
"green mask=0x%lx, blue mask=0x%lx at depth=%d, bpp=%d "
"and byte order=%s\n", r_mask, g_mask, b_mask, depth, bpp,
byte_order[!!byte_order_is_lsb_first]);
return 0;
}
/* If the image is in little-endian then the order in memory is
reversed */
if (byte_order_is_lsb_first &&
_cogl_pixel_format_is_endian_dependant (image_format))
{
image_format ^= COGL_BGR_BIT;
if (image_format & COGL_A_BIT)
image_format ^= COGL_AFIRST_BIT;
}
return image_format;
}
#endif /* _COGL_IN_TEST_BITMASK */