mutter/clutter/clutter-feature.c
Emmanuele Bassi 6d87b1479c 2006-12-04 Emmanuele Bassi <ebassi@openedhand.com>
Avoid clutter segfaulting when used without invoking
	clutter_init().  This is needed when using api documentation
	tools and every other tool relying on the GObject
	introspection API (esp. on a headless box).  see the
	note in clutter/clutter-feature.c:clutter_feature_init
	for a full explanation.

	* clutter/clutter-feature.c: Call clutter_feature_init()
	when needed by one of the accessors of the features
	structure.

	* clutter/clutter-main.c:
	* clutter/clutter-private.h: Remove clutter_feature_init()
	public declaration: the features support check is done the
	first time a feature is needed.

	* clutter/clutter-main.c: Do not ever access the clutter
	main context pointer directly; instead, obtain a pointer
	to it via clutter_context_get_default(), which will always
	return something valid.
2006-12-04 19:19:53 +00:00

391 lines
9.5 KiB
C

/*
* Clutter.
*
* An OpenGL based 'interactive canvas' library.
*
* Authored By Matthew Allum <mallum@openedhand.com>
*
* Copyright (C) 2006 OpenedHand
*
* 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, write to the
* Free Software Foundation, Inc., 59 Temple Place - Suite 330,
* Boston, MA 02111-1307, USA.
*/
/**
* SECTION:clutter-feature
* @short_description: functions to query available GL features ay runtime
*
* Functions to query available GL features ay runtime
*/
#include "config.h"
#include <stdlib.h>
#include <string.h>
#include <sys/types.h>
#include <sys/stat.h>
#include <sys/ioctl.h>
#include <fcntl.h>
#include <errno.h>
#include <dlfcn.h>
#include "clutter-feature.h"
#include "clutter-main.h"
#include "clutter-private.h"
#include "clutter-debug.h"
typedef void (*FuncPtr) (void);
typedef int (*GLXGetVideoSyncProc) (unsigned int *count);
typedef int (*GLXWaitVideoSyncProc) (int divisor,
int remainder,
unsigned int *count);
typedef FuncPtr (*GLXGetProcAddressProc) (const guint8 *procName);
typedef struct ClutterFeatureFuncs
{
GLXGetVideoSyncProc get_video_sync;
GLXWaitVideoSyncProc wait_video_sync;
} ClutterFeatureFuncs;
typedef enum ClutterVBlankType
{
CLUTTER_VBLANK_NONE = 0,
CLUTTER_VBLANK_GLX,
CLUTTER_VBLANK_DRI
} ClutterVBlankType;
typedef struct ClutterFeatures
{
ClutterFeatureFlags flags;
ClutterFeatureFuncs funcs;
gint dri_fd;
ClutterVBlankType vblank_type;
guint features_set : 1;
} ClutterFeatures;
static ClutterFeatures* __features = NULL;
G_LOCK_DEFINE_STATIC (__features);
/* #ifdef linux */
#define DRM_VBLANK_RELATIVE 0x1;
struct drm_wait_vblank_request {
int type;
unsigned int sequence;
unsigned long signal;
};
struct drm_wait_vblank_reply {
int type;
unsigned int sequence;
long tval_sec;
long tval_usec;
};
typedef union drm_wait_vblank {
struct drm_wait_vblank_request request;
struct drm_wait_vblank_reply reply;
} drm_wait_vblank_t;
#define DRM_IOCTL_BASE 'd'
#define DRM_IOWR(nr,type) _IOWR(DRM_IOCTL_BASE,nr,type)
#define DRM_IOCTL_WAIT_VBLANK DRM_IOWR(0x3a, drm_wait_vblank_t)
static int drm_wait_vblank(int fd, drm_wait_vblank_t *vbl)
{
int ret, rc;
do
{
ret = ioctl(fd, DRM_IOCTL_WAIT_VBLANK, vbl);
vbl->request.type &= ~DRM_VBLANK_RELATIVE;
rc = errno;
}
while (ret && rc == EINTR);
return rc;
}
/* #endif */
/* Note must be called after context created */
static gboolean
check_gl_extension (const gchar *name,
const gchar *ext)
{
gchar *end;
gint name_len, n;
if (name == NULL || ext == NULL)
return FALSE;
end = (gchar*)(ext + strlen(ext));
name_len = strlen(name);
while (ext < end)
{
n = strcspn(ext, " ");
if ((name_len == n) && (!strncmp(name, ext, n)))
return TRUE;
ext += (n + 1);
}
return FALSE;
}
static FuncPtr
get_proc_address (const gchar *name)
{
static GLXGetProcAddressProc get_proc_func = NULL;
static void *dlhand = NULL;
if (get_proc_func == NULL && dlhand == NULL)
{
dlhand = dlopen (NULL, RTLD_LAZY);
if (dlhand)
{
dlerror ();
get_proc_func =
(GLXGetProcAddressProc) dlsym (dlhand, "glXGetProcAddress");
if (dlerror () != NULL)
{
get_proc_func =
(GLXGetProcAddressProc) dlsym (dlhand, "glXGetProcAddressARB");
}
if (dlerror () != NULL)
{
get_proc_func = NULL;
g_warning ("failed to bind GLXGetProcAddress "
"or GLXGetProcAddressARB");
}
}
}
if (get_proc_func)
return get_proc_func ((unsigned char*) name);
return NULL;
}
static gboolean
check_vblank_env (const char *name)
{
const char *val;
val = getenv("CLUTTER_VBLANK");
if (val && !strcasecmp(val, name))
return TRUE;
return FALSE;
}
/* clutter_feature_init:
* must be called with the static lock on __features held, to keep it
* mt-safe.
*
* XXX - here we need a bit of weird machinery in place. the features
* are checked at run time, each time we try to access them - unless
* we already checked them once. unfortunately, we need an open
* X display if we want to check them, so ideally we'd need to call
* clutter_init() before checking for any feature. the generator for
* the api documentation, and more in general every tool relying on the
* introspection API provided by GObject, may well not be able to call
* clutter_init() (and neither they should be, as we might be running
* them on a headless build box). so, we need a way to get the features
* without explicitely calling clutter_feature_init() inside clutter_init()
* and we also need to have an open X display when we test for the features.
* __features is dynamically allocated, and applications tend to badly
* crash when trying to access __features; so when can't use a NULL check
* to know whether we already invoked clutter_feature_init() once; hence,
* we must allocate it anyway, and have a flag to let us know when the
* features have been set - that is when clutter_feature_init() has been
* successfully completed with an open X display.
*/
static void
clutter_feature_init (void)
{
const gchar *gl_extensions, *glx_extensions;
CLUTTER_NOTE (MISC, "checking features");
if (!__features)
{
CLUTTER_NOTE (MISC, "allocating features data");
__features = g_new0 (ClutterFeatures, 1);
memset(&__features->funcs, 0, sizeof(ClutterFeatureFuncs));
__features->features_set = FALSE; /* don't rely on zero-ing */
}
if (!clutter_xdisplay ())
return;
if (__features->features_set)
return;
gl_extensions = (const gchar*) glGetString (GL_EXTENSIONS);
glx_extensions = glXQueryExtensionsString (clutter_xdisplay (),
clutter_xscreen ());
if (check_gl_extension ("GL_ARB_texture_rectangle", gl_extensions))
__features->flags |= CLUTTER_FEATURE_TEXTURE_RECTANGLE;
/* vblank */
__features->vblank_type = CLUTTER_VBLANK_NONE;
if (getenv("__GL_SYNC_TO_VBLANK") || check_vblank_env("none"))
{
CLUTTER_NOTE (MISC, "vblank sync: disabled at user request");
}
else
{
if (!check_vblank_env("dri") &&
check_gl_extension ("GLX_SGI_video_sync", glx_extensions))
{
__features->funcs.get_video_sync =
(GLXGetVideoSyncProc) get_proc_address ("glXGetVideoSyncSGI");
__features->funcs.wait_video_sync =
(GLXWaitVideoSyncProc) get_proc_address ("glXWaitVideoSyncSGI");
if ((__features->funcs.get_video_sync != NULL) &&
(__features->funcs.wait_video_sync != NULL))
{
CLUTTER_NOTE (MISC, "vblank sync: using glx");
__features->vblank_type = CLUTTER_VBLANK_GLX;
__features->flags |= CLUTTER_FEATURE_SYNC_TO_VBLANK;
}
}
if (!(__features->flags & CLUTTER_FEATURE_SYNC_TO_VBLANK))
{
__features->dri_fd = open("/dev/dri/card0", O_RDWR);
if (__features->dri_fd >= 0)
{
CLUTTER_NOTE (MISC, "vblank sync: using dri");
__features->vblank_type = CLUTTER_VBLANK_DRI;
__features->flags |= CLUTTER_FEATURE_SYNC_TO_VBLANK;
}
}
if (!(__features->flags & CLUTTER_FEATURE_SYNC_TO_VBLANK))
{
CLUTTER_NOTE (MISC,
"vblank sync: no use-able mechanism found");
}
}
CLUTTER_NOTE (MISC, "features checked");
__features->features_set = TRUE;
}
static void
clutter_feature_do_init (void)
{
G_LOCK (__features);
clutter_feature_init ();
G_UNLOCK (__features);
}
/**
* clutter_feature_available:
* @feature: a #ClutterFeatureFlags
*
* Checks whether @feature is available. @feature can be a logical
* OR of #ClutterFeatureFlags.
*
* Return value: %TRUE if a feature is available
*
* Since: 0.1.1
*/
gboolean
clutter_feature_available (ClutterFeatureFlags feature)
{
clutter_feature_do_init ();
return (__features->flags & feature);
}
/**
* clutter_feature_get_all:
*
* Returns all the supported features.
*
* Return value: a logical OR of all the supported features.
*
* Since: 0.1.1
*/
ClutterFeatureFlags
clutter_feature_get_all (void)
{
clutter_feature_do_init ();
return __features->flags;
}
/**
* clutter_feature_wait_for_vblank:
*
* FIXME
*
* Since: 0.2
*/
void
clutter_feature_wait_for_vblank (void)
{
clutter_feature_do_init ();
switch (__features->vblank_type)
{
case CLUTTER_VBLANK_GLX:
{
unsigned int retraceCount;
__features->funcs.get_video_sync (&retraceCount);
__features->funcs.wait_video_sync (2,
(retraceCount + 1) % 2,
&retraceCount);
}
break;
case CLUTTER_VBLANK_DRI:
{
drm_wait_vblank_t blank;
blank.request.type = DRM_VBLANK_RELATIVE;
blank.request.sequence = 1;
drm_wait_vblank (__features->dri_fd, &blank);
}
break;
case CLUTTER_VBLANK_NONE:
default:
break;
}
}