compositing: Send only one mouse move event if WebRender is in use.
In WebRender mode, we were sending two mouse move events: one with the
proper coordinates and one with the wrong coordinates, because of
incorrect fall-through. The script task would usually (but not always,
depending on timing) ignore the first event in favor of the second
event, resulting in incorrect mouse move event coordinates in most
cases.
Closes servo/webrender#238.
Closes#10298.
r? @metajack
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Removed panicking when frame or pipeline lookup fails.
Removed the methods `pipeline(id)`, `pipeline_mut(id)`, `frame(id)` and `frame_mut(id)` from constellation, which panicked when the table lookup failed.
The panics were causing race conditions, e.g. visiting google.com and resizing the page would cause a panic, most likely due to an iframe being added and removed, with the `DOMLoad` event arriving after the iframe had been removed, causing a panic.
This patch fixes#10017 and #8769 (although in non-webrender builds there's now a different panic, see https://github.com/servo/servo/issues/10017#issuecomment-198160200).
There are a few `TODO` items in the initial commit, for cases where it's not completely obvious what to do in the case of failure.
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In WebRender mode, we were sending two mouse move events: one with the
proper coordinates and one with the wrong coordinates, because of
incorrect fall-through. The script task would usually (but not always,
depending on timing) ignore the first event in favor of the second
event, resulting in incorrect mouse move event coordinates in most
cases.
Closes servo/webrender#238.
Closes#10298.
This changes headless operation to strictly be a runtime option, rather
than a compile-time one. Note that the old headless version still relied
on a display server to support WebGL, while it now requires one all the
time.
Fixes#8573
has loaded.
This avoids a flash of unstyled content, which looks especially bad in
browser.html since unstyled content is white and browser.html has a
transparent background.
Closes#9996.
Fix animation smoothness when using requestAnimationFrame.
Previously, the flow for ticking animations was:
Compositor -> Constellation -> Layout -> Script
However, this means that the compositor <-> layout messages can thrash, meaning layout thread is very rarely idle.
This means that the script thread (which joins on the layout thread during reflow) was unable to execute and run rAF callbacks.
With this change, the flow is now:
Compositor -> Constellation -> Script (when rAF is active).
Compositor -> Constellation -> Layout (when transitions / animations are active and no rAF is present).
This makes rAF based animation *much* smoother.
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Previously, the flow for ticking animations was:
Compositor -> Constellation -> Layout -> Script
However, this means that the compositor <-> layout messages can thrash, meaning layout thread is very rarely idle.
This means that the script thread (which joins on the layout thread during reflow) was unable to execute and run rAF callbacks.
With this change, the flow is now:
Compositor -> Constellation -> Script (when rAF is active).
Compositor -> Constellation -> Layout (when transitions / animations are active and no rAF is present).
This makes rAF based animation *much* smoother.
Instead, schedule a delayed composite after each frame of an animation.
The previous code would cause jank, because the following sequence
frequently occurred:
1. The page uses `requestAnimationFrame()` to request a frame.
2. The compositor receives the message, schedules a composite,
dispatches the rAF message to the script thread, composites, and goes to
sleep waiting for vblank (frame 1).
3. The script makes a change and sends it through the pipeline.
Eventually it gets painted and is sent to the compositor, but the
compositor is sleeping.
4. The compositor wakes up, sees the new painted content, page flips,
and goes to sleep (frame 2). Repeat from step 1.
The problem is that we have two composition frames, not just one. This
halves Web apps' framerate!
This commit fixes the problem by scheduling the composite in step 2 to
12 ms in the future. We already have this delayed-composition
functionality in the form of the scrolling timer, which I repurposed and
renamed to the "delayed composition timer" for this task. This change
gives the page 12 ms to prepare the frame, which seems to usually be
enough, especially with WebRender.
Note that simply removing the scheduled composite after rAF is not the
correct solution. If this is done, then pages that call rAF and don't
modify the page won't receive future rAFs, since the compositor will be
sleeping and won't be notified of vblank.
Fixes a bunch of jank in browser.html. The remaining jank seems to be a
problem with browser.html itself.
WebRender is an experimental GPU accelerated rendering backend for Servo.
The WebRender backend can be specified by running Servo with the -w option (otherwise the default rendering backend will be used).
WebRender has many bugs, and missing features - but it is usable to browse most websites - please report any WebRender specific rendering bugs you encounter!
