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mutter-performance-source/cogl/cogl-feature-private.h
Neil Roberts d259a87602 Don't use the 'NULL' GModule to resolve GL symbols
Previously, _cogl_get_proc_address had a fallback to resolve the
symbol using g_module_open(NULL) to get the symbol from anywhere in
the address space. The EGL backend ends up using this on some drivers
because eglGetProcAddress isn't meant to return a pointer for core
functions. This causes problems if something in the process is linking
against a different GL library, for example Cairo may be linking
against libGL itself. In this case it may end up resolving symbols
from the GL library even if GLES is being used.

This patch removes the fallback. The EGL version now has its own
fallback instead which passes the existing libgl_module from the
renderer to g_module_symbol so that it should only get symbols from
that library or its dependency chain. The GLX and WGL winsys only call
glXGetProcAddress and wglGetProcAddress. The stub winsys does however
continue using the global symbol lookup.

The internal _cogl_get_proc_address function has been renamed to
_cogl_renderer_get_proc_address because it needs a connected renderer
to work so it could be considered to be a renderer method. The pointer
to the renderer is passed down to the winsys backends so that it can
use the data attached to the renderer to get the module pointers.

https://bugzilla.gnome.org/show_bug.cgi?id=655412

Reviewed-by: Robert Bragg <robert@linux.intel.com>
2011-07-27 16:10:02 +01:00

99 lines
3.3 KiB
C

/*
* Cogl
*
* An object oriented GL/GLES Abstraction/Utility Layer
*
* Copyright (C) 2009 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_FEATURE_PRIVATE_H
#define __COGL_FEATURE_PRIVATE_H
#include <glib.h>
#include "cogl-internal.h"
#define COGL_CHECK_GL_VERSION(driver_major, driver_minor, \
target_major, target_minor) \
((driver_major) > (target_major) || \
((driver_major) == (target_major) && (driver_minor) >= (target_minor)))
typedef enum
{
COGL_EXT_IN_GLES = (1 << 0),
COGL_EXT_IN_GLES2 = (1 << 1)
} CoglExtGlesAvailability;
typedef struct _CoglFeatureFunction CoglFeatureFunction;
struct _CoglFeatureFunction
{
/* The name of the function without the "EXT" or "ARB" suffix */
const char *name;
/* The offset in the context of where to store the function pointer */
unsigned int pointer_offset;
};
typedef struct _CoglFeatureData CoglFeatureData;
struct _CoglFeatureData
{
/* A minimum GL version which the functions should be defined in
without needing an extension. Set to 255,255 if it's only
provided in an extension */
int min_gl_major, min_gl_minor;
/* Flags specifying which versions of GLES the feature is available
in core in */
CoglExtGlesAvailability gles_availability;
/* \0 separated list of namespaces to try. Eg "EXT\0ARB\0" */
const char *namespaces;
/* \0 separated list of required extension names without the GL_EXT
or GL_ARB prefix. Any of the extensions must be available for the
feature to be considered available. If the suffix for an
extension is different from the namespace, you can specify it
with a ':' after the namespace */
const char *extension_names;
/* A set of feature flags to enable if the extension is available */
CoglFeatureFlags feature_flags;
/* A set of private feature flags to enable if the extension is
* available */
int feature_flags_private;
/* An optional corresponding winsys feature. */
CoglWinsysFeature winsys_feature;
/* A list of functions required for this feature. Terminated with a
NULL name */
const CoglFeatureFunction *functions;
};
gboolean
_cogl_feature_check (CoglRenderer *renderer,
const char *driver_prefix,
const CoglFeatureData *data,
int gl_major,
int gl_minor,
CoglDriver driver,
const char *extensions_string,
void *function_table);
void
_cogl_feature_check_ext_functions (CoglContext *context,
int gl_major,
int gl_minor,
const char *gl_extensions);
#endif /* __COGL_FEATURE_PRIVATE_H */