A new (internal only currently) API, _clutter_actor_queue_clipped_redraw
can be used to queue a redraw along with a clip rectangle in actor
coordinates. This clip rectangle propagates up to the stage and clutter
backend which may optionally use the information to optimize stage
redraws. The GLX backend in particular may scissor the next redraw to
the clip rectangle and use GLX_MESA_copy_sub_buffer to present the stage
subregion.
The intention is that any actors that can naturally determine the bounds
of updates should queue clipped redraws to reduce the cost of updating
small regions of the screen.
Notes:
» If GLX_MESA_copy_sub_buffer isn't available then the GLX backend
ignores any clip rectangles.
» queuing multiple clipped redraws will result in the bounding box of
each clip rectangle being used.
» If a clipped redraw has a height > 300 pixels then it's promoted into
a full stage redraw, so that the GPU doesn't end up blocking too long
waiting for the vsync to reach the optimal position to avoid tearing.
» Note: no empirical data was used to come up with this threshold so
we may need to tune this.
» Currently only ClutterX11TexturePixmap makes use of this new API. This
is done via a new "queue-damage-redraw" signal that is emitted when
the pixmap is updated. The default handler queues a clipped redraw
with the assumption that the pixmap is being painted as a rectangle
covering the actors transformed allocation. If you subclass
ClutterX11TexturePixmap and change how it's painted you now also
need to override the signal handler and queue your own redraw.
Technically this is a semantic break, but it's assumed that no one
is currently doing this.
This still leaves a few unsolved issues with regards to optimizing sub
stage redraws that need to be addressed in further work so this can only
be considered a stepping stone a this point:
» Because we have no reliable way to determine if the painting of any
given actor is being modified any optimizations implemented using
_clutter_actor_queue_redraw_with_clip must be overridable by a
subclass, and technically must be opt-in for existing classes to avoid
a change in semantics. E.g. consider that a user connects to the paint
signal for ClutterTexture and paints a circle instead of a rectangle.
In this case any original logic to queue clipped redraws would be
incorrect.
» Currently only the implementation of an actor has enough information
with which to queue clipped redraws. E.g. It is not possible for
generic code in clutter-actor.c to queue a clipped redraw when hiding
an actor because actors have no way to report a "paint box". (remember
actors can draw outside their allocation and actors with depth may
also be projected outside of their allocation)
» The current plan is to add a actor_class->get_paint_cuboid()
virtual so actors can report a bounding cube for everything they
would draw in their current state and use that to queue clipped
redraws against the stage by projecting the paint cube into stage
coordinates.
» Our heuristics for promoting clipped redraws into full redraws to
avoid blocking the GPU while we wait for the vsync need improving:
» vsync issues aren't relevant for redirected/composited applications
so they should use different heuristics. In this case we instead
need to trade off the cost of blitting when using glXCopySubBuffer
vs promoting to a full redraw and flipping instead.
Since using addresses that might change is something that finally
the FSF acknowledge as a plausible scenario (after changing address
twice), the license blurb in the source files should use the URI
for getting the license in case the library did not come with it.
Not that URIs cannot possibly change, but at least it's easier to
set up a redirection at the same place.
As a side note: this commit closes the oldes bug in Clutter's bug
report tool.
http://bugzilla.openedhand.com/show_bug.cgi?id=521
If your OpenGL driver supports GLX_INTEL_swap_event that means when
glXSwapBuffers is called it returns immediatly and an XEvent is sent when
the actual swap has finished.
Clutter can use the events that notify swap completion as a means to
throttle rendering in the master clock without blocking the CPU and so it
should help improve the performance of CPU bound applications.
Some extensions only support GLX versions > 1.3 and may not support
old style X Windows as GLXDrawables, so we now create GLXWindows for
stages when possible.
* clutter/Makefile.am:
* clutter/eglx/Makefile.am:
* clutter/eglx/clutter-backend-egl.c:
* clutter/eglx/clutter-backend-egl.h:
* clutter/eglx/clutter-eglx.h:
* clutter/eglx/clutter-event-egl.c:
* clutter/eglx/clutter-stage-egl.c:
* clutter/eglx/clutter-stage-egl.h:
* clutter/glx/Makefile.am:
* clutter/glx/clutter-backend-glx.c:
* clutter/glx/clutter-backend-glx.h:
* clutter/glx/clutter-event-glx.c:
* clutter/glx/clutter-glx.h:
* clutter/glx/clutter-stage-glx.c:
* clutter/glx/clutter-stage-glx.h:
* clutter/x11/Makefile.am:
* clutter/x11/clutter-backend-x11-private.h:
* clutter/x11/clutter-backend-x11.c:
* clutter/x11/clutter-backend-x11.h:
* clutter/x11/clutter-event-x11.c:
* clutter/x11/clutter-stage-x11.c:
* clutter/x11/clutter-stage-x11.h:
* clutter/x11/clutter-x11.h:
Create a new X11 backend class of which EGL and GLX 'real' backends
then subclass. Effectively shares all X11 code between both backends
avoids code duplication and brings many missing features to EGL X
backend. Requires some cleanup and testing. (#518)
* clutter/cogl/gles/cogl.c: (cogl_color):
Add define to use color4ub only if configure finds it.
If not fall back to old code.
* configure.ac:
Drop support for vincent checks.
Drop sdles backend.
Specifically check for color4ub call.
* clutter/clutter-actor.c:
* clutter/clutter-event.h:
* clutter/clutter-main.c:
* clutter/clutter-stage.c:
* clutter/clutter-stage.h:
* clutter/glx/clutter-backend-glx.c:
* clutter/glx/clutter-backend-glx.h:
* clutter/glx/clutter-event-glx.c:
* clutter/glx/clutter-stage-glx.c:
* clutter/glx/clutter-stage-glx.h:
Add initial support for stage state events.
Fix fullscreening for an already mapped stage.
* tests/test-events.c:
Print out info from the above. Blue button now toggles
fullscreen.
* clutter/clutter-effect.c:
* clutter/clutter-effect.h:
Add a setting for templates to ref or clone underlying
timelines. (As to improve sync issues like those in foofone)
* tests/test-timeline.c:
Also add completed signals.
* clutter/cogl/gles/cogl.c: (cogl_texture_image_2d):
* configure.ac:
Forward port from stable branch. RGB Image fixes gles
and check for lower case libgles_cm.
* clutter/clutter-private.h: Remove inclusion of backend-specific
headers; update the main context object; add the declarations for
the event queue functions.
* clutter/clutter-backend.[ch]: Add the abstract ClutterBackend
object, which holds backend-specific settings, the main stage,
and the event queue. Every backend must implement a subclass of
ClutterBackend and ClutterStage.
* clutter/clutter-feature.c: Protect the GLX specific calls
behing #ifdef HAVE_CLUTTER_GLX.
* clutter/clutter-actor.c:
* clutter/clutter-group.c:
* clutter/clutter-clone-texture.c: Include GL/gl.h
* clutter/clutter-event.[ch]: Update public API and implement the
event queue private API; hold a reference on the event objects;
move out the keysym-to-unicode table; add the new event types.
* clutter/clutter-color.h: Include clutter-fixed.h
* clutter/clutter-main.c: Update API; get the main stage
from the backend object; process the event received from the
queue; lock/unlock the main mutex if we have one; move the
initialisation process sooner in the init sequence, in order to
have the backend object when we check for options; call the
backed vfuncs in the pre/post parse hooks.
* clutter/clutter-stage.c: Make ClutterStage and abstract class,
implemented by the backends.
* clutter/clutter/glx/clutter-glx.h:
* clutter/clutter/glx/clutter-backend-glx.[ch]:
* clutter/clutter/glx/clutter-event-glx.c:
* clutter/clutter/glx/clutter-stage-glx.[ch]:
* clutter/clutter/glx/Makefile.am: Add the GLX backend.
* clutter/clutter/egl/clutter-backend-egl.[ch]:
* clutter/clutter/egl/clutter-event-egl.c:
* clutter/clutter/egl/clutter-stage-egl.[ch]:
* clutter/clutter/egl/Makefile.am: Add the stub for a EGL backend.
* examples/*.c: Update for the new API.
