Interpolating between two transformations expressed using a 3D matrix
can be achieved by decomposing the matrices into their transformations
and do a simple numeric interpolation between the initial and final
states, like we do for other data types.
Luckily for us, the CSS Transforms specification from the W3C provides
the decomposition algorithm, using the "unmatrix" code taken from the
book "Graphics Gems II, edited by Jim Arvo".
Once the matrices have been decomposed, we can simply interpolate the
transformations, and re-apply them onto the result matrix, using the
facilities that Clutter provides for interpolating between two known
GTypes.
Acquiring the Clutter lock to mark critical sections is not portable,
and not recommended to implement threaded applications with Clutter.
The recommended pattern is to use worker threads, and schedule UI
updates inside idle or timeout handlers within the main loop. We should
enforce this pattern by deprecating the threads_enter()/leave()
functions. For compatibility concerns, we need internal API to acquire
the main lock during frame processing dispatch.
https://bugzilla.gnome.org/show_bug.cgi?id=679450
Clutter is meant to be, and I quote from the README, a toolkit:
for creating fast, compelling, portable, and dynamic graphical
user interfaces
and yet the default mode of operation for setting an actor's state on
the scene graph (position, size, opacity, rotation, scaling, depth,
etc.) is *not* dynamic. We assume a static UI, and then animate it.
This is the wrong way to design an API for a toolkit meant to be used to
create animated user interfaces. The default mode of operation should be
to implicitly animate every state transition, and only allow skipping
the animation if the user consciously decides to do so — i.e. the design
tenet of the API should be to make The Right Thing™ by default, and make
it really hard (or even impossible) to do The Wrong Thing™.
So we should identify "animatable" properties, i.e. those properties
that should be implicitly animated by ClutterActor, and use the
animation framework we provide to tween the transitions between the
current state and the desired state; the implicit animation should
happen when setting these properties using the public accessors, and not
through some added functionality. For instance, the following:
clutter_actor_set_position (actor, newX, newY);
should not make the actor jump to the (newX, newY) point; it should
tween the actor's position between the current point and the desired
point.
Since we have to maintain backward compatibility with existing
applications, we still need to mark the transitions explicitly, but we
can be smart about it, and treat transition states as a stack that can
be pushed and popped, e.g.:
clutter_actor_save_easing_state (actor);
clutter_actor_set_easing_duration (actor, 500);
clutter_actor_set_position (actor, newX, newY);
clutter_actor_set_opacity (actor, newOpacity);
clutter_actor_restore_easing_state (actor);
And we can even start stacking animations, e.g.:
clutter_actor_save_easing_state (actor);
clutter_actor_set_easing_duration (actor, 500);
clutter_actor_set_position (actor, newX, newY);
clutter_actor_save_easing_state (actor);
clutter_actor_set_easing_duration (actor, 500);
clutter_actor_set_easing_mode (actor, CLUTTER_LINEAR);
clutter_actor_set_opacity (actor, newOpacity);
clutter_actor_set_depth (actor, newDepth);
clutter_actor_restore_easing_state (actor);
clutter_actor_restore_easing_state (actor);
And so on, and so forth.
The implementation takes advantage of the newly added Transition API,
which uses only ClutterTimeline sub-classes and ClutterInterval, to cut
down the amount of signal emissions and memory management of object
instances; as well of using the ClutterAnimatable interface for custom
properties and interpolation of values.
As a convenience for the C API.
Language bindings should already be using the GValue variants.
This commit also moves the custom progress functions out of the
clutter-interval.c, as they are meant to be generic interpolation
functions and not ClutterInterval-specific.
It is sometimes useful to be able to have better control on when a
repaint function is called. Currently, all repaint functions are called
prior to the stages update phase of the frame processing.
We can introduce flags to represent the point in the frame update
process in which we wish Clutter called the repaint function.
As a bonus, we can also add a flag that causes adding a repaint function
to spin the master clock.
GLib has a "diagnostic mode" switch that can be checked to enable debug
messages on deprecated properties and signals, as these are purely
run-time constructs, and as such cannot be caught by compiler warnings.
The diagnostic mode is toggled by a simple environment variable, and
can be used to ease porting of application code.
We can use something similar to mark deprecated virtual functions and
other run-time constructs; to avoid collisions, we should use our own
environment variable, CLUTTER_ENABLE_DIAGNOSTIC.
We still ship clutter_get_show_fps() and clutter_get_debug_enabled() as
public entry points. Yet another case of missing API review prior to the
1.0 release, so really the bucket stops around my desk.
Let's deprecate these two useless functions, and reduce the API
footprint of Clutter.
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
The repaint functions list can (and should) be manipulated from
different threads, but it currently doesn't prevent multiple threads
from accessing it concurrently. We should have a simple lock and take it
when adding and removing elements from the list; the invocation is still
performed under the Big Clutter Lock™, so it doesn't require special
handling.
This is a replacement for the nearbyint function which always rounds to
the nearest integer. nearbyint is a C99 function so it might not always
be available but also it seems in glibc it is defined as a function call
so this macro could end up faster anyway. We can't just add 0.5 because
it will break for negative numbers.
Signed-off-by: Neil Roberts <neil@linux.intel.com>
Signed-off-by: Emmanuele Bassi <ebassi@linux.intel.com>
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.
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.
In Cogl, cogl-pango.h has moved to <cogl-pango/cogl-pango.h>. When
using the experimental 2.0 API (which Clutter does) it is no longer
possible to include it under the old name of <cogl/cogl-pango.h> so we
need to update the include location.
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
Cogl has now been split out into a standalone project with a separate
repository at git://git.gnome.org/cogl. From now on the Clutter build
will now simply look for a cogl-1.0 pkg-config file to find a suitable
Cogl library to link against at build time.
This makes it possible to build Clutter against a standalone build of
Cogl instead of having the Clutter build traverse into the clutter/cogl
subdirectory.
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.
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.
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.
Only allow access to the ClutterMainContext through the private
_clutter_context_get_default() function, so we can easily grep
it and remove the unwanted usage of the global context.
The shader stack held by ClutterMainContext should only be accessed
using functions, and not directly.
Since it's a stack, we can use stack-like operations: push, pop and
peek.
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.
As the prelude to deprecation of the function in 1.8, let's move the
implementation to an internal function, and use that instead of the
public facing one.
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.
This is a lump commit that is fairly difficult to break down without
either breaking bisecting or breaking the test cases.
The new design for handling X11 event translation works this way:
- ClutterBackend::translate_event() has been added as the central
point used by a ClutterBackend implementation to translate a
native event into a ClutterEvent;
- ClutterEventTranslator is a private interface that should be
implemented by backend-specific objects, like stage
implementations and ClutterDeviceManager sub-classes, and
allows dealing with class-specific event translation;
- ClutterStageX11 implements EventTranslator, and deals with the
stage-relative X11 events coming from the X11 event source;
- ClutterStageGLX overrides EventTranslator, in order to
deal with the INTEL_GLX_swap_event extension, and it chains up
to the X11 default implementation;
- ClutterDeviceManagerX11 has been split into two separate classes,
one that deals with core and (optionally) XI1 events, and the
other that deals with XI2 events; the selection is done at run-time,
since the core+XI1 and XI2 mechanisms are mutually exclusive.
All the other backends we officially support still use their own
custom event source and translation function, but the end goal is to
migrate them to the translate_event() virtual function, and have the
event source be a shared part of Clutter core.
Move the private Backend API to a separate header.
This also allows us to finally move the class vtable and instance
structure to a separate file and plug the visibility hole that left
the Backend class bare for everyone to poke into.
