Commit Graph

37 Commits

Author SHA1 Message Date
Robert Bragg
a0441778ad This re-licenses Cogl 1.18 under the MIT license
Since the Cogl 1.18 branch is actively maintained in parallel with the
master branch; this is a counter part to commit 1b83ef938fc16b which
re-licensed the master branch to use the MIT license.

This re-licensing is a follow up to the proposal that was sent to the
Cogl mailing list:
http://lists.freedesktop.org/archives/cogl/2013-December/001465.html

Note: there was a copyright assignment policy in place for Clutter (and
therefore Cogl which was part of Clutter at the time) until the 11th of
June 2010 and so we only checked the details after that point (commit
0bbf50f905)

For each file, authors were identified via this Git command:
$ git blame -p -C -C -C20 -M -M10  0bbf50f905..HEAD

We received blanket approvals for re-licensing all Red Hat and Collabora
contributions which reduced how many people needed to be contacted
individually:
- http://lists.freedesktop.org/archives/cogl/2013-December/001470.html
- http://lists.freedesktop.org/archives/cogl/2014-January/001536.html

Individual approval requests were sent to all the other identified authors
who all confirmed the re-license on the Cogl mailinglist:
http://lists.freedesktop.org/archives/cogl/2014-January

As well as updating the copyright header in all sources files, the
COPYING file has been updated to reflect the license change and also
document the other licenses used in Cogl such as the SGI Free Software
License B, version 2.0 and the 3-clause BSD license.

This patch was not simply cherry-picked from master; but the same
methodology was used to check the source files.
2014-02-22 02:02:53 +00:00
Daniel Stone
ea7d3b8476 Add fence API
cogl_framebuffer_add_fence creates a synchronisation fence, which will
invoke a user-specified callback when the GPU has finished executing all
commands provided to it up to that point in time.

Support is currently provided for GL 3.x's GL_ARB_sync extension, and
EGL's EGL_KHR_fence_sync (when used with OpenGL ES).

Signed-off-by: Daniel Stone <daniel@fooishbar.org>
Reviewed-by: Neil Roberts <neil@linux.intel.com>
Reviewed-by: Robert Bragg <robert@linux.intel.com>

https://bugzilla.gnome.org/show_bug.cgi?id=691752

(cherry picked from commit e6d37470da9294adc1554c0a8c91aa2af560ed9f)
2013-05-28 21:36:03 +01:00
Robert Bragg
3a7c1263f1 onscreen: Adds swap_buffers_with_damage api
This adds api to be able requests a swap_buffers and also pass a list of
damage rectangles that can be passed on to a compositor to enable it to
minimize how much of the screen it needs to recompose.

Reviewed-by: Neil Roberts <neil@linux.intel.com>

(cherry picked from commit 0d9684c7b7c2018bb42715c369555330d38514a2)
2013-04-30 16:39:31 +01:00
Robert Bragg
95a41e177a Associate check and dispatch funcs with poll fds
Instead of driving event dispatching through a per winsys poll_dispatch
vfunc its now possible to associate a check and dispatch function with
each file descriptor that is registered for polling. This means we can
remove the winsys get_dispatch_timeout and poll_dispatch vfuncs and it
also makes it easier for more orthogonal internal components to add file
descriptors for polling to the mainloop.

Reviewed-by: Neil Roberts <neil@linux.intel.com>

(cherry picked from commit 627947622df36dd529b9dc60a3ae9e6083532b19)
2013-04-30 16:39:31 +01:00
Robert Bragg
ed90c6fed9 Move event polling into CoglRenderer
This updates the cogl_poll_ apis to allow dispatching events before we
have a CoglContext and to also enables pollfd state to be changed in a
more add-hoc way by different Cogl components by replacing the
winsys->get_poll_info with _cogl_poll_renderer_add/remove_fd functions
and a winsys->get_dispatch_timeout vfunc.

One of the intentions here is that applications should be able to run
their mainloop before creating a CoglContext to potentially get events
relating to CoglOutputs.

Reviewed-by: Neil Roberts <neil@linux.intel.com>

(cherry picked from commit 667e58c9cb2662aef5f44e580a9eda42dc8d0176)
2013-04-30 16:39:31 +01:00
Owen W. Taylor
98e3b57d0d Add cogl_get_clock_time()
Add an API to get the current time in the time system that Cogl
is reporting timestamps. This is to be used to convert timestamps
into a different time system.

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

(cherry picked from commit 9f3735a0c37adcfcffa485f81699b53a4cc0caf8)
2013-01-30 20:09:49 +00:00
Owen W. Taylor
88d8bd84f2 Add CoglOutput and track for the GLX backend
The CoglOutput object represents one output such as a monitor or
laptop panel, with information about attributes of the output such as
the position of the output within the global coordinate space, and
the refresh rate.

We don't yet publically export the ability to get output information but
we track it for the GLX backend, where we'll use it to track the refresh
rate.

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

(cherry picked from commit d7ef9d8d71488d0e6874f1ffc6e48700d5c82a31)
2013-01-30 19:56:45 +00:00
Adel Gadllah
860fb00fdc cogl-onscreen: Add buffer_age support
Add a new BUFFER_AGE winsys feature and a get_buffer_age method to
cogl-onscreen that allows to query the value.

https://bugzilla.gnome.org/show_bug.cgi?id=669122

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

Note: When landing the patch I made some gtk-doc updates and changed
_get_buffer_age to return an age of 0 always if the age feature isn't
support instead of using _COGL_RETURN_VAL_IF_FAIL. -- Robert Bragg

(cherry picked from commit 427b1038051e9b53a071d8c229b363b075bb1dc0)
2013-01-23 17:58:10 +00:00
Robert Bragg
df21e20f65 Adds CoglError api
Although we use GLib internally in Cogl we would rather not leak GLib
api through Cogl's own api, except through explicitly namespaced
cogl_glib_ / cogl_gtype_ feature apis.

One of the benefits we see to not leaking GLib through Cogl's public API
is that documentation for Cogl won't need to first introduce the Glib
API to newcomers, thus hopefully lowering the barrier to learning Cogl.

This patch provides a Cogl specific typedef for reporting runtime errors
which by no coincidence matches the typedef for GError exactly.  If Cogl
is built with --enable-glib (default) then developers can even safely
assume that a CoglError is a GError under the hood.

This patch also enforces a consistent policy for when NULL is passed as
an error argument and an error is thrown. In this case we log the error
and abort the application, instead of silently ignoring it. In common
cases where nothing has been implemented to handle a particular error
and/or where applications are just printing the error and aborting
themselves then this saves some typing. This also seems more consistent
with language based exceptions which usually cause a program to abort if
they are not explicitly caught (which passing a non-NULL error signifies
in this case)

Since this policy for NULL error pointers is stricter than the standard
GError convention, there is a clear note in the documentation to warn
developers that are used to using the GError api.

Reviewed-by: Neil Roberts <neil@linux.intel.com>

(cherry picked from commit b068d5ea09ab32c37e8c965fc8582c85d1b2db46)

Note: Since we can't change the Cogl 1.x api the patch was changed to
not rename _error_quark() functions to be _error_domain() functions and
although it's a bit ugly, instead of providing our own CoglError type
that's compatible with GError we simply #define CoglError to GError
unless Cogl is built with glib disabled.

Note: this patch does technically introduce an API break since it drops
the cogl_error_get_type() symbol generated by glib-mkenum (Since the
CoglError enum was replaced by a CoglSystemError enum) but for now we
are assuming that this will not affect anyone currently using the Cogl
API. If this does turn out to be a problem in practice then we would be
able to fix this my manually copying an implementation of
cogl_error_get_type() generated by glib-mkenum into a compatibility
source file and we could also define the original COGL_ERROR_ enums for
compatibility too.

Note: another minor concern with cherry-picking this patch to the 1.14
branch is that an api scanner would be lead to believe that some APIs
have changed, and for example the gobject-introspection parser which
understands the semantics of GError will not understand the semantics of
CoglError. We expect most people that have tried to use
gobject-introspection with Cogl already understand though that it is not
well suited to generating bindings of the Cogl api anyway and we aren't
aware or anyone depending on such bindings for apis involving GErrors.
(GnomeShell only makes very-very minimal use of Cogl via the gjs
bindings for the cogl_rectangle and cogl_color apis.)

The main reason we have cherry-picked this patch to the 1.14 branch
even given the above concerns is that without it it would become very
awkward for us to cherry-pick other beneficial patches from master.
2013-01-22 17:47:39 +00:00
Tomeu Vizoso
bb258c1d42 Avoid including the EGL headers from the public Cogl headers
Otherwise, X11 identifiers may leak and cause havoc in big applications

Reviewed-by: Neil Roberts <neil@linux.intel.com>

(cherry picked from commit ed0cdca0eca815543619fe72fbd42d662d53f92d)
2012-08-06 18:51:32 +01:00
Robert Bragg
df51574116 onscreen: Adds support for resizable windows
This adds api to be able to request that the window system allows a
given onscreen framebuffer to be resizable, and api to add and remove
resize handlers to be called whenever the framebuffer does actually
change size.

The new functions are:
  cogl_onscreen_{get,set}_resizable()
  cogl_onscreen_{add,remove}_resize_handler()

The examples cogl-hello and cogl-x11-foreign have been updated to use
the new api. To smoke test how Cogl updates the viewport automatically
in response to window resizes the cogl-hello test doesn't explicitly
respond to resize events by setting the viewport and cogl-x11-foreign
responds by setting a viewport that is offset by a quarter of the
window's width/height and half the width and height of the window.

Reviewed-by: Neil Roberts <neil@linux.intel.com>

(cherry picked from commit a1a8cc00bfa2cecaf1007aec5f3dd95dc07b1786)
2012-08-06 18:51:32 +01:00
Neil Roberts
df77e8565e Don't use eglGetProcAddress to retrieve core functions
According to the EGL spec, eglGetProcAddress should only be used to
retrieve extension functions. It also says that returning non-NULL
does not mean the extension is available so you could interpret this
as saying that the function is allowed to return garbage for core
functions. This seems to happen at least for the Android
implementation of EGL.

To workaround this the winsys's are now passed down a flag to say
whether the function is from the core API. This information is already
in the gl-prototypes headers as the minimum core GL version and as a
pair of flags to specify whether it is available in core GLES1 and
GLES2. If the function is in core the EGL winsys will now avoid using
eglGetProcAddress and always fallback to querying the library directly
with the GModule API.

The GLX winsys is left alone because glXGetProcAddress apparently
supports querying core API and extension functions.

The WGL winsys could ideally be changed because wglGetProcAddress
should also only be used for extension functions but the situation is
slightly different because WGL considers anything from GL > 1.1 to be
an extension so it would need a bit more information to determine
whether to query the function directly from the library.

The SDL winsys is also left alone because it's not as easy to portably
determine which GL library SDL has chosen to load in order to resolve
the symbols directly.

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

(cherry picked from commit 72089730ad06ccdd38a344279a893965ae68cec1)

  Since we aren't able to break API on the 1.12 branch
  cogl_get_proc_address is still supported but isn't easily able to
  determine whether the given name corresponds to a core symbol or
  not.  For now we just assume the symbol being queried isn't part
  of the core GL api and update the documentation accordingly.
2012-08-06 14:27:45 +01:00
Robert Bragg
010d16f647 Adds initial GLES2 integration support
This makes it possible to integrate existing GLES2 code with
applications using Cogl as the rendering api.

Currently all GLES2 usage is handled with separate GLES2 contexts to
ensure that GLES2 api usage doesn't interfere with Cogl's own use of
OpenGL[ES]. The api has been designed though so we can provide tighter
integration later.

The api would allow us to support GLES2 virtualized on top of an
OpenGL/GLX driver as well as GLES2 virtualized on the core rendering api
of Cogl itself. Virtualizing the GLES2 support on Cogl will allow us to
take advantage of Cogl debugging facilities as well as let us optimize
the cost of allocating multiple GLES2 contexts and switching between
them which can both be very expensive with many drivers.

As as a side effect of this patch Cogl can also now be used as a
portable window system binding API for GLES2 as an alternative to EGL.

Parts of this patch are based on work done by Tomeu Vizoso
<tomeu.vizoso@collabora.com> who did the first iteration of adding GLES2
API support to Cogl so that WebGL support could be added to
webkit-clutter.

This patch adds a very minimal cogl-gles2-context example that shows how
to create a gles2 context, clear the screen to a random color and also
draw a triangle with the cogl api.

Reviewed-by: Neil Roberts <neil@linux.intel.com>
(cherry picked from commit 4bb6eff3dbd50d8fef7d6bdbed55c5aaa70036a8)
2012-08-06 14:27:42 +01:00
Robert Bragg
54735dec84 Switch use of primitive glib types to c99 equivalents
The coding style has for a long time said to avoid using redundant glib
data types such as gint or gchar etc because we feel that they make the
code look unnecessarily foreign to developers coming from outside of the
Gnome developer community.

Note: When we tried to find the historical rationale for the types we
just found that they were apparently only added for consistent syntax
highlighting which didn't seem that compelling.

Up until now we have been continuing to use some of the platform
specific type such as gint{8,16,32,64} and gsize but this patch switches
us over to using the standard c99 equivalents instead so we can further
ensure that our code looks familiar to the widest range of C developers
who might potentially contribute to Cogl.

So instead of using the gint{8,16,32,64} and guint{8,16,32,64} types this
switches all Cogl code to instead use the int{8,16,32,64}_t and
uint{8,16,32,64}_t c99 types instead.

Instead of gsize we now use size_t

For now we are not going to use the c99 _Bool type and instead we have
introduced a new CoglBool type to use instead of gboolean.

Reviewed-by: Neil Roberts <neil@linux.intel.com>

(cherry picked from commit 5967dad2400d32ca6319cef6cb572e81bf2c15f0)
2012-08-06 14:27:39 +01:00
Robert Bragg
09642a83b5 Removes all remaining use of CoglHandle
Removing CoglHandle has been an on going goal for quite a long time now
and finally this patch removes the last remaining uses of the CoglHandle
type and the cogl_handle_ apis.

Since the big remaining users of CoglHandle were the cogl_program_ and
cogl_shader_ apis which have replaced with the CoglSnippets api this
patch removes both of these apis.

Reviewed-by: Neil Roberts <neil@linux.intel.com>

(cherry picked from commit 6ed3aaf4be21d605a1ed3176b3ea825933f85cf0)

  Since the original patch was done after removing deprecated API
  this back ported patch doesn't affect deprecated API and so
  actually this cherry-pick doesn't remove all remaining use of
  CoglHandle as it did for the master branch of Cogl.
2012-08-06 14:27:39 +01:00
Robert Bragg
680f63a48c Remove all internal includes of cogl.h
The cogl.h header is meant to be the public header for including the 1.x
api used by Clutter so we should stop using that as a convenient way to
include all likely prototypes and typedefs. Actually we already do a
good job of listing the specific headers we depend on in each of the .c
files we have so mostly this patch just strip out the redundant
includes for cogl.h with a few fixups where that broke the build.

Reviewed-by: Neil Roberts <neil@linux.intel.com>
2012-02-20 23:12:45 +00:00
Neil Roberts
99c651d2b4 Move the add_swap_buffers_callback functions out of the winsys
Instead of having each winsys implement its own list of callbacks the
list is now just attached directly to the CoglOnscreen using code in
cogl-onscreen.c. The winsys's can invoke this list of callbacks by
calling _cogl_onscreen_notify_swap_buffers(). All of the winsys's
would probably have a very similar implementation for this anyway and
I don't think it makes much sense to try and save the cost of a list
pointer in the CoglOnscreen struct.

Reviewed-by: Robert Bragg <robert@linux.intel.com>
2012-02-08 17:00:25 +00:00
Robert Bragg
a8513c1d77 renderer: Adds api to add/remove selection constraints
This allows applications to specify certain constraints that feed into
the process of selecting a CoglRenderer backend. For example
applications might depend on x11 for handling input and so they require
a backend that's also based on x11.
2012-01-16 18:27:19 +00:00
Neil Roberts
7497475295 Add support for main loop integration
This adds two new functions:

void
cogl_poll_get_info (CoglContext *context,
                    CoglPollFD **poll_fds,
                    int *n_poll_fds,
                    gint64 *timeout);

void
cogl_poll_dispatch (CoglContext *context,
                    const CoglPollFD *poll_fds,
                    int n_poll_fds);

The application is expected to call the first function whenever it is
about to block to go idle, and the second function whenever it comes
out of idle. This gives Cogl winsys's the ability poll file
descriptors for events. For example when handing swap complete
notifications, it can report that it needs to block on a file
descriptor.

The two functions are backed by winsys virtual functions. There are
currently no implementations. The default handler for get_info just
reports no file descriptors and an infinite timeout.

Reviewed-by: Robert Bragg <robert@linux.intel.com>
2012-01-05 13:40:10 +00:00
Neil Roberts
616d27f169 cogl-texture-2d: Fix checking for the EGL winsys
CoglTexture2D had an assert to verify that the EGL winsys was being
used. This doesn't make any sense any more because the EGL winsys
can't be used directly but instead it is just a base winsys for the
platform winsys's. To fix this this patch adds a set of 'criteria'
flags to each winsys, one of which is 'uses EGL'. CoglTexture2D can
use this to determine if the winsys is supported.

Eventually we might want to expose these flags publically so that an
application can select a winsys based on certain conditions. For
example, an application may need a winsys that uses X or EGL but
doesn't care exactly which one it is.

Reviewed-by: Robert Bragg <robert@linux.intel.com>
2011-12-14 16:41:16 +00:00
Robert Bragg
79719347c8 framebuffer: split out CoglOnscreen code
This factors out the CoglOnscreen code from cogl-framebuffer.c so we now
have cogl-onscreen.c, cogl-onscreen.h and cogl-onscreen-private.h.
Notably some of the functions pulled out are currently namespaced as
cogl_framebuffer but we know we are planning on renaming them to be in
the cogl_onscreen namespace; such as cogl_framebuffer_swap_buffers().

Reviewed-by: Neil Roberts <neil@linux.intel.com>
2011-11-01 12:03:02 +00:00
Robert Bragg
3a2f94045e framebuffer: make _swap_region coords top-left relative
Cogl aims to consistently put the origin of 2D objects at the top-left
instead of the bottom left as OpenGL does, but there was an oversight
and the experimental cogl_framebuffer_swap_region API was accepting
coordinates relative to the bottom left. Cogl will now flip the user's
given rectangles to be relative to the bottom of the framebufffer before
sending them to APIs like glXCopySubBuffer and glBlitFramebuffer.

Reviewed-by: Neil Roberts <neil@linux.intel.com>
2011-08-12 15:28:43 +01:00
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
Robert Bragg
b3a105c576 renderer: Expose winsys ID setter/getters
This adds API to let you override the choice of Cogl's winsys backend.
Previously it was only possible to override the winsys using the
COGL_RENDERER environment variable, but it's useful for something like
Clutter to be able to control the winsys via API without needing
environment variable tricks. This also adds API to query back the
winsys chosen by Cogl, in case you don't set an explicit override.

Signed-off-by: Neil Roberts <neil@linux.intel.com>
2011-06-30 14:33:11 +01:00
Robert Bragg
be15bf75e4 Add internal _cogl_get_proc_address
This adds an internal _cogl_get_proc_address that doesn't need a
CoglContext. This will enable us to check driver features earlier.
2011-06-01 20:44:41 +01:00
Neil Roberts
6788c80342 Add a WGL winsys
This adds a full winsys to handle WGL and Win32.
2011-05-10 17:58:41 +01:00
Neil Roberts
14d1303259 cogl-winsys: Explicitly comment which vfuncs are optional
Some of the virtual functions in CoglWinsysVtable only need to be
implemented for specific backends or when a specific feature is
advertised. This splits the vtable struct into two commented sections
marking which are optional and which are required. Wherever an
optional function is used there is now a g_return_if_fail to ensure
there is an implementation.
2011-05-10 17:15:22 +01:00
Neil Roberts
614efb190b cogl-winsys: Remove the get_vsync_counter virtual
This function is only used internally within the GLX winsys so there
doesn't seem to be much point in it being a virtual winsys backend
function.
2011-05-10 17:13:23 +01:00
Neil Roberts
f2a37b27f9 CoglWinsysVtable: Remove 'has_feature'
This virtual function is no longer used or defined anywhere since the
function was moved to the common backend code in 16bfa27d43.
2011-05-10 17:13:23 +01:00
Robert Bragg
97243ad9ac Adds cogl_onscreen_show/hide functions
This adds Cogl API to show and hide onscreen framebuffers. We don't want
to go too far down the road of abstracting window system APIs with Cogl
since that would be out of its scope but the previous idea that we would
automatically map framebuffers on allocation except for those made from
foreign windows wasn't good enough. The problem is that we don't want to
make Clutter always create stages from foreign windows but with the
automatic map semantics then Clutter doesn't get an opportunity to
select for all the events it requires before mapping. This meant that we
wouldn't be delivered a mouse enter event for windows mapped underneath
the cursor which would break Clutters handling of button press events.
2011-05-05 15:05:42 +01:00
Robert Bragg
ad56c00f7a Add missing _cogl_winsys_has_feature prototype
This adds a private prototype for _cogl_winsys_has_feature in
cogl-winsys-private.h to avoid compilation warnings.
2011-05-05 15:05:42 +01:00
Robert Bragg
31ee65784d winsys: Expose environment variable to choose winsys
This makes it possible to override the winsys that cogl uses by setting
the COGL_RENDERER environment variable e.g. to "GLX" or "EGL"
2011-05-05 14:46:01 +01:00
Robert Bragg
dc7383b714 Add a vtable of indirection to the winsys code
So that we can dynamically select what winsys backend to use at runtime
we need to have some indirection to how code accesses the winsys instead
of simply calling _cogl_winsys* functions that would collide if we
wanted to compile more than one backend into Cogl.
2011-05-05 14:46:01 +01:00
Robert Bragg
d52e3f0cc2 texture-pixmap-x11: Move GLX code to cogl-winsys-glx.c
This moves the GLX specific code from cogl-texture-pixmap-x11.c into
cogl-winsys-glx.c. If we want the winsys components to by dynamically
loadable then we can't have GLX code scattered outside of
cogl-winsys-glx.c. This also sets us up for supporting the
EGL_texture_from_pixmap extension which is almost identical to the
GLX_texture_from_pixmap extension.
2011-05-05 14:46:01 +01:00
Robert Bragg
d5d11f1878 Moves all EGL code down from Clutter to Cogl
As was recently done for the GLX window system code, this commit moves
the EGL window system code down from the Clutter backend code into a
Cogl winsys.

Note: currently the cogl/configure.ac is hard coded to only build the GLX
winsys so currently this is only available when building Cogl as part
of Clutter.
2011-05-05 14:46:01 +01:00
Robert Bragg
d40cdfa3e1 Moves all GLX code down from Clutter to Cogl
This migrates all the GLX window system code down from the Clutter
backend code into a Cogl winsys. Moving OpenGL window system binding
code down from Clutter into Cogl is the biggest blocker to having Cogl
become a standalone 3D graphics library, so this is an important step in
that direction.
2011-04-11 17:54:36 +01:00
Robert Bragg
e80a2b9b2f rename winsys files to be more consistent
This tries to make the naming style of files under cogl/winsys/
consistent with other cogl source files. In particular private header
files didn't have a '-private' infix.
2011-04-11 17:54:35 +01:00