The default stage was a neat concept when we started Clutter out,
somewhere in the Jurassic era; a singleton instance that gets created at
initialization time, and remains the same for the entire duration of the
process.
Worked well enough when Clutter was a small library meant to be used to
write fullscreen media browsers, but since the introduction of multiple
stages, and Clutter being used to create all sorts of applications, the
default stage is just a vestigial remainder of that past, like an
appendix; something that complicates the layout of the code and
introduces weird behaviour, so that you notice its existence only when
something goes wrong.
Some platforms we do support, though, only have one framebuffer, so it
makes sense for them to have only one stage.
At this point, the only sane thing to do is to go through the same code
paths on all platforms, and that code path is the stage instance
creation and initialization — i.e. clutter_stage_new() (or
g_object_new() with CLUTTER_TYPE_STAGE).
For platforms that support multiple stages, nothing has changed: the stage
created by clutter_stage_get_default() will be set as the default one;
if nobody calls it, the default stage is never created, and it just
lives on as a meaningless check.
For platforms that only support one stage, clutter_stage_new() and
clutter_stage_get_default() will behave exactly the same the first time
they are called: both will create a stage, and set it as the default.
Calling clutter_stage_new() a second time is treated as a programmer
error, and will result in Clutter aborting. This is a behavioural change
because the existing behaviour or creating a new ClutterStage instance
with the same ClutterStageWindow private implementation is, simply put,
utterly braindamaged and I should have *never* had written it, and I
apologize for it. In my defence, I didn't know any better at the time.
This is the first step towards the complete deprecation of
clutter_stage_get_default() and clutter_stage_is_default(), which will
come later.
The ClutterGeometry type is a poor substitute of cairo_rectangle_int_t,
with unsigned integers for width and height to complicate matters.
Let's remove the internal usage of ClutterGeometry and switch to the
rectangle type from Cairo.
https://bugzilla.gnome.org/show_bug.cgi?id=656663
This implicitly intersects any clip for redrawing with the stage window
bounds. Without this we were sometimes trying to set huge off screen
scissors leading to undefined clipping results.
Reviewed-by: Emmanuele Bassi <ebassi@linux.intel.com>
When picking we need to disable dithering to be sure that the hardware
will not modify the colors we use as actor identifiers. Clutter was
manually calling glEnable/Disable GL_DITHER to handle this, but that was
a layering violation since Cogl is intended to handle all interactions
with OpenGL. Since we are now striving for GL vs GLES to be a runtime
choice we need to remove this last direct usage of GL from Clutter so it
doesn't have to be linked with GL at build time.
Signed-off-by: Neil Roberts <neil@linux.intel.com>
This adds a public function to get the bounds of the current clipped
redraw on a stage. This should only be called while the stage is being
painted. The function diverts to a virtual function on the
ClutterStageWindow implementation. If the function isn't implemented
or it returns FALSE then the entire stage is reported. The clip bounds
are in integer pixel coordinates in the stage's coordinate space.
http://bugzilla.clutter-project.org/show_bug.cgi?id=2421
It is possible, by calling clutter_set_motion_events_enabled() prior to
the creation of any stage, to control the per-actor motion event
delivery flag on each newly created stage. Since we deprecated the
global accessor functions in favour of the per-Stage ones, we need to
remove the call to clutter_get_motion_events_enabled() inside the
ClutterStage instance initialization, and replace it with an internal
function.
This code will go away when we can finally break API and remove the
deprecated functions.
Complete the quest of commit bc548dc862
by making the ClutterStage methods for controlling the per-actor motion
and crossing event delivery public, and deprecating the global ones.
Since eef9078f the translation of the camera away from the z=zero
plane was hardcoded at 50 which is approximately half way between the
default z_near and z_far values. This ended up with quite a small
distance in user-space coordinates to the far plane with the default
stage size and this was causing test-texture-quality to clip the actor
early.
This patch makes it try to calculate a reasonable value for the
position of the z=0 plane as well as a value for z_far so we maximize
the space in between the z=0 plane and the near plane and we have a
predictable amount of space behind the stage before hitting the far
clipping plane, while considering the trade off of loosing depth
precision by pushing the far plane too far back relative to the near
plane.
With the default fov of 60° it's not possible to use the stage size to
define the gap in-front of the stage plane; only ~87% of the stage size
is possible as an upper limit. We make 85% of the stage_height available
assuming you have a fov of 60°. We consistently provide 10 times the
stage height of space behind the stage regardless of the fov.
It seems worth noting here that we went around in circles a few times
over how to calculate the gaps since there are a number of trade offs to
consider and they also affect the complexity of the solution. In the end
we went for simplicity but commented the issues well enough hopefully so
we can develop a more elaborate solution if we ever have a use-case.
http://bugzilla.clutter-project.org/show_bug.cgi?id=2625
Since eef9078f ClutterStage updates the aspect ratio of the
perspective matrix whenever the size of the stage changes. This meant
that if an application tries to set its own perspective matrix then
part of it would get overridden. It's not really clear what the
use-case of setting the perspective on the stage should be but it
seems like the safest bet is to always try to preserve the
application's request. The documentation for the function has been
tweaked to discourage its use.
http://bugzilla.clutter-project.org/show_bug.cgi?id=2625
cairo.h is intended to be included as <cairo.h> not <cairo/cairo.h> as
is the style for clutter.h. If you have installed cairo to a custom
prefix then using cairo/cairo.h can result in unintentional use of the
system cairo headers, or if they aren't installed then it will result in
a failure to find the header.
The G_CONST_RETURN define in GLib is, and has always been, a bit fuzzy.
We always used it to conform to the platform, at least for public-facing
API.
At first I assumed it has something to do with brain-damaged compilers
or with weird platforms where const was not really supported; sadly,
it's something much, much worse: it's a define that can be toggled at
compile-time to remove const from the signature of public API. This is a
truly terrifying feature that I assume was added in the past century,
and whose inception clearly had something to do with massive doses of
absynthe and opium — because any other explanation would make the
existence of such a feature even worse than assuming drugs had anything
to do with it.
Anyway, and pleasing the gods, this dubious feature is being
removed/deprecated in GLib; see bug:
https://bugzilla.gnome.org/show_bug.cgi?id=644611
Before deprecation, though, we should just remove its usage from the
whole API. We should especially remove its usage from Cally's internals,
since there it never made sense in the first place.
_clutter_stage_do_pick called by interactive picking and
clutter_stage_get_actor_at_pos could be accidentally reading back the wrong
actor id's if an other stage has had a more recent render due to animation.
This should resolve some multi stage / ClutterGtk related pick id warnings.
The id pool used for the actor's id should be a per-stage field. At some
point, we might have a Stage mapped to multiple framebuffers, or each
Stage mapped to a different framebuffer; also, on backend with low
color precision we don't want to exhaust the size of the available ids
with a global pool. Finally, it's yet another thing we can remove from
the global Clutter context.
Having the id pool allocated per-stage, and the pick id assigned on
Actor:mapped will make the whole pick-id more reliable and future proof.
http://bugzilla.clutter-project.org/show_bug.cgi?id=2633https://bugzilla.gnome.org/show_bug.cgi?id=647876
Do not use GdkPixbuf just for getting image data down into a PNG; Cairo
is perfectly capable of doing the same, at least just for debugging
purposes.
https://bugzilla.gnome.org/show_bug.cgi?id=647875
Do not use the generic GType class name: we have a :name property on
ClutterActor that is generally used for debugging purposes — so we
should use it when creating debugging spew in a consistent way.
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.
This gives us a way to clearly track the internal Cogl API that Clutter
depends on. The aim is to split Cogl out from Clutter into a standalone
3D graphics API and eventually we want to get rid of any private
interfaces for Clutter so its useful to have a handle on that task.
Actually it's not as bad as I was expecting though.
This adds an internal _clutter_stage_get_active_framebuffer function
that can be used to get a pointer to the current CoglFramebuffer pointer
that is in use, in association with a given stage.
The "active" infix in the function name is there because we shouldn't
assume that a stage will always correspond to only a single framebuffer
so we aren't getting a pointer to a sole framebuffer, we are getting
a pointer to the framebuffer that is currently in use/being painted.
This API is now used for culling purposes where we need to check if we
are currently painting an actor to a framebuffer that is offscreen, that
doesn't correspond to the stage.
This moves the implementation of _clutter_do_pick to clutter-stage.c and
renames it _clutter_stage_do_pick. This function can be compared to
_clutter_stage_do_update/redraw in that it prepares for and starts a
traversal of a scenegraph descending from a given stage. Since it is
desirable that this function should have access to the private state of
the stage it is awkward to maintain outside of clutter-stage.c.
Besides moving _clutter_do_pick this patch is also able to remove the
following private state accessors from clutter-stage-private.h:
_clutter_stage_set_pick_buffer_valid,
_clutter_stage_get_pick_buffer_valid,
_clutter_stage_increment_picks_per_frame_counter,
_clutter_stage_reset_picks_per_frame_counter and
_clutter_stage_get_picks_per_frame_counter.
To give quick visibility to the things going on relating to clipping and
culling this adds some more CLIPPING debug notes to clutter-actor.c and
clutter-stage.c
This implements a variation of frustum culling whereby we convert screen
space clip rectangles into eye space mini-frustums so that we don't have
to repeatedly transform actor paint-volumes all the way into screen
coordinates to perform culling, we just have to apply the modelview
transform and then determine each points distance from the planes that
make up the clip frustum.
By avoiding the projective transform, perspective divide and viewport
scale for each point culled this makes culling much cheaper.
This simplifies the implementation of the ClutterStage apply_transform
vfunc by using the new cogl_matrix_view_2d_in_perspective utility API
which can setup up a view transform for a given perspective so that a
cross section of the view frustum at an arbitrary depth can be mapped
directly to 2D stage coordinates with (0,0) at the top left.
Firstly Clutter shouldn't be using OpenGL directly so this needed
changing but also conceptually it doesn't make sense for
clutter_stage_read_pixels to validate the requested area to read against
the viewport it would make more sense to compare against the window
size. Finally checking that the width of the area is less than the
viewport or window width without considering the x isn't enough to know
if the area extends outside the windows bounds. (same for the height)
This patch removes the validation of the read area from
clutter_stage_read_pixels and instead we now simply rely on the
semantics of cogl_read_pixels for reading areas outside the window
bounds.
OpenGL < 4.0 only supports integer based viewports and internally we
have a mixture of code using floats and integers for viewports. This
patch switches all viewports throughout clutter and cogl to be
represented using floats considering that in the future we may want to
take advantage of floating point viewports with modern hardware/drivers.
Once upon a time, the land of Clutter had a stage singleton. It was
created automatically at initialization time and stayed around even
after the main loop was terminated. The singleton was content in
being all there was. There also was a global API to handle the
configuration of the stage singleton that would affect the behaviour
on other classes, signals and properties.
Then, an evil wizard came along and locked the stage singleton in his
black tower, and twisted it until it was possible to create new stages.
These new stages were pesky, and didn't have the same semantics of the
singleton: they didn't stay around when closed, or terminate the main
loop on delete events.
The evil wizard also started moving all the stage-related API from the
global context into class-specific methods.
Finally, the evil wizard cast a spell, and the stage singleton was
demoted to creation on demand - and until somebody called the
clutter_stage_get_default() function, the singleton remained in a limbo
of NULL pointers and undefined memory areas.
There was a last bit - literally - of information still held by the
global API; a tiny, little flag that disabled per-actor motion events.
The evil wizard added private accessors for it, and stored it inside the
stage private structure, in preparation for a deprecation that would
come in a future development cycle.
The evil wizard looked down upon the land of Clutter from the height of
his black tower; the lay of the land had been reshaped into a crucible
of potential, and the last dregs of the original force of creation were
either molted into new, useful shapes, or blasted away by the sheer fury
of his will.
All was good.
The _clutter_do_redraw() function should really be moved inside
ClutterStage, since all it does is calling private stage and
backend functions. This also allows us to change a long-standing
issue with a global fps counter for all stages, instead of a\
per-stage one.
Since we realize on creation we need to unrealize on destruction. This
makes sure that the ClutterStageWindow implementation can tear down any
resource set up during the realization phase.
http://bugzilla.clutter-project.org/show_bug.cgi?id=2559
The GQueue that stores the global events queue is handled all over the
place:
• the structure is created in _clutter_backend_init_events();
• the queue is handled in clutter-event.c, clutter-stage.c and
clutter-backend.c;
• ClutterStage::dispose cleans up the events associated with
the stage being destroyed;
• the queue is destroyed in ClutterBackend::dispose.
Since we need to have access to it in different places we cannot put it
inside ClutterBackendPrivate, hence it should stay in ClutterMainContext;
but we should still manage it from just one place - preferably by the
ClutterEvent API only.
Clutter should just require that the windowing system used by a backend
adds a device to the stage when the device enters, and removes it from
the stage when the device leaves; with this information, we can
synthesize every crossing event and update the device state without
other intervention from the backend-specific code.
The generation of additional crossing events for actors that are
covering the stage at the coordinates of the crossing event should be
delegated to the event processing code.
The x11 and win32 backends need to be modified to relay the enter and
leave events from the windowing system.
Allow the developer to set whether the Stage should receive key focus
when mapped. The implementation is fully backend-dependent. The default
value is TRUE because that's what we've been expecting so far.
http://bugzilla.clutter-project.org/show_bug.cgi?id=2500
If an actor is (unfortunately) queuing a relayout in relayout, you would
end up with (ClutterActor*)stage->needs_allocation set to TRUE and
stage->relayout_pending set to TRUE. But if then in the same cycle, an
actor calls clutter_actor_get_allocation_box, that will trigger another
(recursive) _clutter_stage_maybe_relayout, which will wrongly reset the
relayout pending to FALSE, while not actually performing a new relayout
because of the re-entrancy protection.
http://bugzilla.clutter-project.org/show_bug.cgi?id=2503
