mutter/cogl/cogl-feature-private.c
Neil Roberts 2616ae0fa9 Add a GL 3 driver
This adds a new CoglDriver for GL 3 called COGL_DRIVER_GL3. When
requested, the GLX, EGL and SDL2 winsyss will set the necessary
attributes to request a forward-compatible core profile 3.1 context.
That means it will have no deprecated features.

To simplify the explosion of checks for specific combinations of
context->driver, many of these conditionals have now been replaced
with private feature flags that are checked instead. The GL and GLES
drivers now initialise these private feature flags depending on which
driver is used.

The fixed function backends now explicitly check whether the fixed
function private feature is available which means the GL3 driver will
fall back to always using the GLSL progend. Since Rob's latest patches
the GLSL progend no longer uses any fixed function API anyway so it
should just work.

The driver is currently lower priority than COGL_DRIVER_GL so it will
not be used unless it is specificly requested. We may want to change
this priority at some point because apparently Mesa can make some
memory savings if a core profile context is used.

In GL 3, getting the combined extensions string with glGetString is
deprecated so this patch changes it to use glGetStringi to build up an
array of extensions instead. _cogl_context_get_gl_extensions now
returns this array instead of trying to return a const string. The
caller is expected to free the array.

Some issues with this patch:

• GL 3 does not support GL_ALPHA format textures. We should probably
  make this a feature flag or something. Cogl uses this to render text
  which currently just throws a GL error and breaks so it's pretty
  important to do something about this before considering the GL3
  driver to be stable.

• GL 3 doesn't support client side vertex buffers. This probably
  doesn't matter because CoglBuffer won't normally use malloc'd
  buffers if VBOs are available, but it might but worth making
  malloc'd buffers a private feature and forcing it not to use them.

• GL 3 doesn't support the default vertex array object. This patch
  just makes it create and bind a single non-default vertex array
  object which gets used just like the normal default object. Ideally
  it would be good to use vertex array objects properly and attach
  them to a CoglPrimitive to cache the state.

Reviewed-by: Robert Bragg <robert@linux.intel.com>

(cherry picked from commit 66c9db993595b3a22e63f4c201ea468bc9b88cb6)
2013-01-22 17:48:01 +00:00

208 lines
6.9 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/>.
*
*
*/
#ifdef HAVE_CONFIG_H
#include "config.h"
#endif
#include <string.h>
#include "cogl-context-private.h"
#include "cogl-feature-private.h"
#include "cogl-renderer-private.h"
#include "cogl-private.h"
CoglBool
_cogl_feature_check (CoglRenderer *renderer,
const char *driver_prefix,
const CoglFeatureData *data,
int gl_major,
int gl_minor,
CoglDriver driver,
char * const *extensions,
void *function_table)
{
const char *suffix = NULL;
int func_num;
CoglBool in_core;
/* First check whether the functions should be directly provided by
GL */
if (((driver == COGL_DRIVER_GL ||
driver == COGL_DRIVER_GL3) &&
COGL_CHECK_GL_VERSION (gl_major, gl_minor,
data->min_gl_major, data->min_gl_minor)) ||
(driver == COGL_DRIVER_GLES1 &&
(data->gles_availability & COGL_EXT_IN_GLES)) ||
(driver == COGL_DRIVER_GLES2 &&
(data->gles_availability & COGL_EXT_IN_GLES2)))
{
suffix = "";
in_core = TRUE;
}
else
{
/* Otherwise try all of the extensions */
const char *namespace, *namespace_suffix;
unsigned int namespace_len;
for (namespace = data->namespaces;
*namespace;
namespace += strlen (namespace) + 1)
{
const char *extension;
GString *full_extension_name = g_string_new ("");
/* If the namespace part contains a ':' then the suffix for
the function names is different from the name space */
if ((namespace_suffix = strchr (namespace, ':')))
{
namespace_len = namespace_suffix - namespace;
namespace_suffix++;
}
else
{
namespace_len = strlen (namespace);
namespace_suffix = namespace;
}
for (extension = data->extension_names;
*extension;
extension += strlen (extension) + 1)
{
g_string_assign (full_extension_name, driver_prefix);
g_string_append_c (full_extension_name, '_');
g_string_append_len (full_extension_name,
namespace, namespace_len);
g_string_append_c (full_extension_name, '_');
g_string_append (full_extension_name, extension);
if (_cogl_check_extension (full_extension_name->str,
extensions))
break;
}
g_string_free (full_extension_name, TRUE);
/* If we found an extension with this namespace then use it
as the suffix */
if (*extension)
{
suffix = namespace_suffix;
break;
}
}
in_core = FALSE;
}
/* If we couldn't find anything that provides the functions then
give up */
if (suffix == NULL)
goto error;
/* Try to get all of the entry points */
for (func_num = 0; data->functions[func_num].name; func_num++)
{
void *func;
char *full_function_name;
full_function_name = g_strconcat (data->functions[func_num].name,
suffix, NULL);
func = _cogl_renderer_get_proc_address (renderer,
full_function_name,
in_core);
g_free (full_function_name);
if (func == NULL)
goto error;
/* Set the function pointer in the context */
*(void **) ((uint8_t *) function_table +
data->functions[func_num].pointer_offset) = func;
}
return TRUE;
/* If the extension isn't found or one of the functions wasn't found
* then set all of the functions pointers to NULL so Cogl can safely
* do feature testing by just looking at the function pointers */
error:
for (func_num = 0; data->functions[func_num].name; func_num++)
*(void **) ((uint8_t *) function_table +
data->functions[func_num].pointer_offset) = NULL;
return FALSE;
}
/* Define a set of arrays containing the functions required from GL
for each feature */
#define COGL_EXT_BEGIN(name, \
min_gl_major, min_gl_minor, \
gles_availability, \
namespaces, extension_names) \
static const CoglFeatureFunction cogl_ext_ ## name ## _funcs[] = {
#define COGL_EXT_FUNCTION(ret, name, args) \
{ G_STRINGIFY (name), G_STRUCT_OFFSET (CoglContext, name) },
#define COGL_EXT_END() \
{ NULL, 0 }, \
};
#include "gl-prototypes/cogl-all-functions.h"
/* Define an array of features */
#undef COGL_EXT_BEGIN
#define COGL_EXT_BEGIN(name, \
min_gl_major, min_gl_minor, \
gles_availability, \
namespaces, extension_names) \
{ min_gl_major, min_gl_minor, gles_availability, namespaces, \
extension_names, 0, 0, 0, \
cogl_ext_ ## name ## _funcs },
#undef COGL_EXT_FUNCTION
#define COGL_EXT_FUNCTION(ret, name, args)
#undef COGL_EXT_END
#define COGL_EXT_END()
static const CoglFeatureData
cogl_feature_ext_functions_data[] =
{
#include "gl-prototypes/cogl-all-functions.h"
};
void
_cogl_feature_check_ext_functions (CoglContext *context,
int gl_major,
int gl_minor,
char * const *gl_extensions)
{
int i;
for (i = 0; i < G_N_ELEMENTS (cogl_feature_ext_functions_data); i++)
_cogl_feature_check (context->display->renderer,
"GL", cogl_feature_ext_functions_data + i,
gl_major, gl_minor, context->driver,
gl_extensions,
context);
}