mutter/cogl/cogl-private.h
Robert Bragg 07e972505c Adds _cogl_pixel_format_is_endian_dependant api
This adds an internal utility function
_cogl_pixel_format_is_endian_dependant() that can query whether
accessing the components of a given format depends on the endianness of
the current host CPU or whether a pixel can be loaded as a word and
channels accessed using bit masking and shifting.

Reviewed-by: Neil Roberts <neil@linux.intel.com>
2012-02-20 23:12:44 +00:00

108 lines
3.3 KiB
C

/*
* Cogl
*
* An object oriented GL/GLES Abstraction/Utility Layer
*
* Copyright (C) 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_PRIVATE_H__
#define __COGL_PRIVATE_H__
#include <cogl/cogl-pipeline.h>
#include "cogl-context.h"
G_BEGIN_DECLS
gboolean
_cogl_gl_update_features (CoglContext *context,
GError **error);
gboolean
_cogl_gles_update_features (CoglContext *context,
GError **error);
gboolean
_cogl_check_extension (const char *name, const char *ext);
void
_cogl_clear (const CoglColor *color, unsigned long buffers);
void
_cogl_read_pixels_with_rowstride (int x,
int y,
int width,
int height,
CoglReadPixelsFlags source,
CoglPixelFormat format,
guint8 *pixels,
int rowstride);
void
_cogl_init (void);
void
_cogl_push_source (CoglPipeline *pipeline, gboolean enable_legacy);
gboolean
_cogl_get_enable_legacy_state (void);
/*
* _cogl_pixel_format_get_bytes_per_pixel:
* @format: a #CoglPixelFormat
*
* Queries how many bytes a pixel of the given @format takes.
*
* Return value: The number of bytes taken for a pixel of the given
* @format.
*/
int
_cogl_pixel_format_get_bytes_per_pixel (CoglPixelFormat format);
/*
* _cogl_pixel_format_has_aligned_components:
* @format: a #CoglPixelFormat
*
* Queries whether the ordering of the components for the given
* @format depend on the endianness of the host CPU or if the
* components can be accessed using bit shifting and bitmasking by
* loading a whole pixel into a word.
*
* XXX: If we ever consider making something like this public we
* should really try to think of a better name and come up with
* much clearer documentation since it really depends on what
* point of view you consider this from whether a format like
* COGL_PIXEL_FORMAT_RGBA_8888 is endian dependent. E.g. If you
* read an RGBA_8888 pixel into a uint32
* it's endian dependent how you mask out the different channels.
* But If you already have separate color components and you want
* to write them to an RGBA_8888 pixel then the bytes can be
* written sequentially regardless of the endianness.
*
* Return value: %TRUE if you need to consider the host CPU
* endianness when dealing with the given @format
* else %FALSE.
*/
gboolean
_cogl_pixel_format_is_endian_dependant (CoglPixelFormat format);
G_END_DECLS
#endif /* __COGL_PRIVATE_H__ */