mutter/cogl/cogl-feature-private.h
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

100 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;
};
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);
void
_cogl_feature_check_ext_functions (CoglContext *context,
int gl_major,
int gl_minor,
char * const *gl_extensions);
#endif /* __COGL_FEATURE_PRIVATE_H */