mutter/cogl/driver/gl/cogl-gl.c
Neil Roberts b2e735ff7f Dynamically load the GL or GLES library
The GL or GLES library is now dynamically loaded by the CoglRenderer
so that it can choose between GL, GLES1 and GLES2 at runtime. The
library is loaded by the renderer because it needs to be done before
calling eglInitialize. There is a new environment variable called
COGL_DRIVER to choose between gl, gles1 or gles2.

The #ifdefs for HAVE_COGL_GL, HAVE_COGL_GLES and HAVE_COGL_GLES2 have
been changed so that they don't assume the ifdefs are mutually
exclusive. They haven't been removed entirely so that it's possible to
compile the GLES backends without the the enums from the GL headers.

When using GLX the winsys additionally dynamically loads libGL because
that also contains the GLX API. It can't be linked in directly because
that would probably conflict with the GLES API if the EGL is
selected. When compiling with EGL support the library links directly
to libEGL because it doesn't contain any GL API so it shouldn't have
any conflicts.

When building for WGL or OSX Cogl still directly links against the GL
API so there is a #define in config.h so that Cogl won't try to dlopen
the library.

Cogl-pango previously had a #ifdef to detect when the GL backend is
used so that it can sneakily pass GL_QUADS to
cogl_vertex_buffer_draw. This is now changed so that it queries the
CoglContext for the backend. However to get this to work Cogl now
needs to export the _cogl_context_get_default symbol and cogl-pango
needs some extra -I flags to so that it can include
cogl-context-private.h
2011-07-11 12:57:38 +01:00

232 lines
7.0 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-private.h"
#include "cogl-internal.h"
#include "cogl-context-private.h"
#include "cogl-feature-private.h"
static gboolean
_cogl_get_gl_version (int *major_out, int *minor_out)
{
const char *version_string, *major_end, *minor_end;
int major = 0, minor = 0;
_COGL_GET_CONTEXT (ctx, FALSE);
/* Get the OpenGL version number */
if ((version_string = (const char *) ctx->glGetString (GL_VERSION)) == NULL)
return FALSE;
/* Extract the major number */
for (major_end = version_string; *major_end >= '0'
&& *major_end <= '9'; major_end++)
major = (major * 10) + *major_end - '0';
/* If there were no digits or the major number isn't followed by a
dot then it is invalid */
if (major_end == version_string || *major_end != '.')
return FALSE;
/* Extract the minor number */
for (minor_end = major_end + 1; *minor_end >= '0'
&& *minor_end <= '9'; minor_end++)
minor = (minor * 10) + *minor_end - '0';
/* If there were no digits or there is an unexpected character then
it is invalid */
if (minor_end == major_end + 1
|| (*minor_end && *minor_end != ' ' && *minor_end != '.'))
return FALSE;
*major_out = major;
*minor_out = minor;
return TRUE;
}
gboolean
_cogl_gl_check_gl_version (CoglContext *ctx,
GError **error)
{
int major, minor;
const char *gl_extensions;
if (!_cogl_get_gl_version (&major, &minor))
{
g_set_error (error,
COGL_DRIVER_ERROR,
COGL_DRIVER_ERROR_UNKNOWN_VERSION,
"The OpenGL version could not be determined");
return FALSE;
}
/* GL 1.3 supports all of the required functionality in core */
if (COGL_CHECK_GL_VERSION (major, minor, 1, 3))
return TRUE;
gl_extensions = (const char*) ctx->glGetString (GL_EXTENSIONS);
/* OpenGL 1.2 is only supported if we have the multitexturing
extension */
if (!_cogl_check_extension ("GL_ARB_multitexture", gl_extensions))
{
g_set_error (error,
COGL_DRIVER_ERROR,
COGL_DRIVER_ERROR_INVALID_VERSION,
"The OpenGL driver is missing "
"the GL_ARB_multitexture extension");
return FALSE;
}
/* OpenGL 1.2 is required */
if (!COGL_CHECK_GL_VERSION (major, minor, 1, 2))
{
g_set_error (error,
COGL_DRIVER_ERROR,
COGL_DRIVER_ERROR_INVALID_VERSION,
"The OpenGL version of your driver (%i.%i) "
"is not compatible with Cogl",
major, minor);
return FALSE;
}
return TRUE;
}
/* Query the GL extensions and lookup the corresponding function
* pointers. Theoretically the list of extensions can change for
* different GL contexts so it is the winsys backend's responsiblity
* to know when to re-query the GL extensions. */
void
_cogl_gl_update_features (CoglContext *context)
{
CoglPrivateFeatureFlags private_flags = 0;
CoglFeatureFlags flags = 0;
const char *gl_extensions;
int max_clip_planes = 0;
int num_stencil_bits = 0;
int gl_major = 0, gl_minor = 0;
_COGL_GET_CONTEXT (ctx, NO_RETVAL);
/* 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_get_proc_address (_cogl_context_get_winsys (context),
"glGetString");
COGL_NOTE (WINSYS,
"Checking features\n"
" GL_VENDOR: %s\n"
" GL_RENDERER: %s\n"
" GL_VERSION: %s\n"
" GL_EXTENSIONS: %s",
ctx->glGetString (GL_VENDOR),
ctx->glGetString (GL_RENDERER),
ctx->glGetString (GL_VERSION),
ctx->glGetString (GL_EXTENSIONS));
_cogl_get_gl_version (&gl_major, &gl_minor);
flags = (COGL_FEATURE_TEXTURE_READ_PIXELS
| COGL_FEATURE_UNSIGNED_INT_INDICES
| COGL_FEATURE_DEPTH_RANGE);
gl_extensions = (const char *)ctx->glGetString (GL_EXTENSIONS);
_cogl_feature_check_ext_functions (context,
gl_major,
gl_minor,
gl_extensions);
if (COGL_CHECK_GL_VERSION (gl_major, gl_minor, 2, 0) ||
_cogl_check_extension ("GL_ARB_texture_non_power_of_two", gl_extensions))
{
flags |= COGL_FEATURE_TEXTURE_NPOT
| COGL_FEATURE_TEXTURE_NPOT_BASIC
| COGL_FEATURE_TEXTURE_NPOT_MIPMAP
| COGL_FEATURE_TEXTURE_NPOT_REPEAT;
}
#ifdef GL_YCBCR_MESA
if (_cogl_check_extension ("GL_MESA_ycbcr_texture", gl_extensions))
{
flags |= COGL_FEATURE_TEXTURE_YUV;
}
#endif
GE( ctx, 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;
GE( ctx, glGetIntegerv (GL_MAX_CLIP_PLANES, &max_clip_planes) );
if (max_clip_planes >= 4)
flags |= COGL_FEATURE_FOUR_CLIP_PLANES;
if (context->glGenRenderbuffers)
flags |= COGL_FEATURE_OFFSCREEN;
if (context->glBlitFramebuffer)
flags |= COGL_FEATURE_OFFSCREEN_BLIT;
if (context->glRenderbufferStorageMultisample)
flags |= COGL_FEATURE_OFFSCREEN_MULTISAMPLE;
if (COGL_CHECK_GL_VERSION (gl_major, gl_minor, 2, 1) ||
_cogl_check_extension ("GL_EXT_pixel_buffer_object", gl_extensions))
flags |= COGL_FEATURE_PBOS;
if (context->glGenPrograms)
flags |= COGL_FEATURE_SHADERS_ARBFP;
if (context->glCreateProgram)
flags |= COGL_FEATURE_SHADERS_GLSL;
if (context->glGenBuffers)
flags |= (COGL_FEATURE_VBOS |
COGL_FEATURE_MAP_BUFFER_FOR_READ |
COGL_FEATURE_MAP_BUFFER_FOR_WRITE);
if (_cogl_check_extension ("GL_ARB_texture_rectangle", gl_extensions))
flags |= COGL_FEATURE_TEXTURE_RECTANGLE;
if (context->glTexImage3D)
flags |= COGL_FEATURE_TEXTURE_3D;
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;
}