mutter/cogl/driver/gles/cogl-gles.c
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

132 lines
4.2 KiB
C

/*
* Cogl
*
* An object oriented GL/GLES Abstraction/Utility Layer
*
* Copyright (C) 2007,2008,2009 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/>.
*
*
*/
#ifdef HAVE_CONFIG_H
#include "config.h"
#endif
#include <string.h>
#include "cogl.h"
#include "cogl-internal.h"
#include "cogl-context-private.h"
#include "cogl-feature-private.h"
#include "cogl-renderer-private.h"
gboolean
_cogl_gles_update_features (CoglContext *context,
GError **error)
{
CoglPrivateFeatureFlags private_flags = 0;
CoglFeatureFlags flags = 0;
const char *gl_extensions;
int num_stencil_bits = 0;
/* We have to special case getting the pointer to the glGetString
function because we need to use it to determine what functions we
can expect */
context->glGetString =
(void *) _cogl_renderer_get_proc_address (context->display->renderer,
"glGetString");
COGL_NOTE (WINSYS,
"Checking features\n"
" GL_VENDOR: %s\n"
" GL_RENDERER: %s\n"
" GL_VERSION: %s\n"
" GL_EXTENSIONS: %s",
context->glGetString (GL_VENDOR),
context->glGetString (GL_RENDERER),
context->glGetString (GL_VERSION),
context->glGetString (GL_EXTENSIONS));
gl_extensions = (const char*) context->glGetString (GL_EXTENSIONS);
_cogl_feature_check_ext_functions (context,
-1 /* GL major version */,
-1 /* GL minor version */,
gl_extensions);
GE( context, glGetIntegerv (GL_STENCIL_BITS, &num_stencil_bits) );
/* We need at least three stencil bits to combine clips */
if (num_stencil_bits > 2)
flags |= COGL_FEATURE_STENCIL_BUFFER;
#ifdef HAVE_COGL_GLES
if (context->driver == COGL_DRIVER_GLES1)
{
int max_clip_planes;
GE( context, glGetIntegerv (GL_MAX_CLIP_PLANES, &max_clip_planes) );
if (max_clip_planes >= 4)
flags |= COGL_FEATURE_FOUR_CLIP_PLANES;
}
#endif
if (context->driver == COGL_DRIVER_GLES2)
{
flags |= COGL_FEATURE_SHADERS_GLSL | COGL_FEATURE_OFFSCREEN;
/* Note GLES 2 core doesn't support mipmaps for npot textures or
* repeat modes other than CLAMP_TO_EDGE. */
flags |= COGL_FEATURE_TEXTURE_NPOT_BASIC;
flags |= COGL_FEATURE_DEPTH_RANGE;
}
flags |= COGL_FEATURE_VBOS;
/* Both GLES 1.1 and GLES 2.0 support point sprites in core */
flags |= COGL_FEATURE_POINT_SPRITE;
if (context->glGenRenderbuffers)
flags |= COGL_FEATURE_OFFSCREEN;
if (context->glBlitFramebuffer)
flags |= COGL_FEATURE_OFFSCREEN_BLIT;
if (_cogl_check_extension ("GL_OES_element_index_uint", gl_extensions))
flags |= COGL_FEATURE_UNSIGNED_INT_INDICES;
if (_cogl_check_extension ("GL_OES_texture_npot", gl_extensions) ||
_cogl_check_extension ("GL_IMG_texture_npot", gl_extensions))
flags |= (COGL_FEATURE_TEXTURE_NPOT |
COGL_FEATURE_TEXTURE_NPOT_BASIC |
COGL_FEATURE_TEXTURE_NPOT_MIPMAP |
COGL_FEATURE_TEXTURE_NPOT_REPEAT);
if (context->glTexImage3D)
flags |= COGL_FEATURE_TEXTURE_3D;
if (context->glMapBuffer)
/* The GL_OES_mapbuffer extension doesn't support mapping for
read */
flags |= COGL_FEATURE_MAP_BUFFER_FOR_WRITE;
if (context->glEGLImageTargetTexture2D)
private_flags |= COGL_PRIVATE_FEATURE_TEXTURE_2D_FROM_EGL_IMAGE;
/* Cache features */
context->private_feature_flags |= private_flags;
context->feature_flags |= flags;
return TRUE;
}