Implement the set_acquire_fence request of the
zwp_surface_synchronization_v1 interface.
The implementation uses the acquire fence in two ways:
1. If the associated buffer is used as GL render source, an
EGLSyncKHR is created from the fence and used to synchronize
access.
2. If the associated buffer is used as a plane framebuffer,
the acquire fence is treated as an in-fence for the atomic
commit operation. If in-fences are not supported and the buffer
has an acquire fence, we don't consider it for plane placement.
If the used compositor/renderer doesn't support explicit
synchronization, we don't advertise the protocol at all. Currently only
the DRM and X11 backends when using the GL renderer advertise the
protocol for production use.
Issues for discussion
---------------------
a. Currently, a server-side wait of EGLSyncKHR is performed before
using the EGLImage/texture during rendering. Unfortunately, it's not clear
from the specs whether this is generally safe to do, or we need to
sync before glEGLImageTargetTexture2DOES. The exception is
TEXTURE_EXTERNAL_OES where the spec mentions it's enough to sync
and then glBindTexture for any changes to take effect.
Changes in v5:
- Meson support.
- Make explicit sync server error reporting more generic, supporting
all explicit sync related interfaces not just
wp_linux_surface_synchronization.
- Fix typo in warning for missing EGL_KHR_wait_sync extension.
- Support minor version 2 of the explicit sync protocol (i.e., support
fences for opaque EGL buffers).
Changes in v4:
- Introduce and use fd_clear and and fd_move helpers.
- Don't check for a valid buffer when updating surface acquire fence fd
from state.
- Assert that pending state acquire fence fd is always clear
after a commit.
- Clarify that WESTON_CAP_EXPLICIT_SYNC applies to just the
renderer.
- Check for EGL_KHR_wait_sync before using eglWaitSyncKHR.
- Dup the acquire fence before passing to EGL.
Changes in v3:
- Keep acquire_fence_fd in surface instead of buffer.
- Clarify that WESTON_CAP_EXPLICIT_SYNC applies to both backend and
renderer.
- Move comment about non-ownership of in_fence_fd to struct
drm_plane_state definition.
- Assert that we don't try to use planes with in-fences when using the
legacy KMS API.
- Remove unnecessary info from wayland error messages.
- Handle acquire fence for subsurface commits.
- Guard against self-update in fd_update.
- Disconnect the client if acquire fence EGLSyncKHR creation or wait
fails.
- Use updated protocol interface names.
- User correct format specifier for resource ids.
- Advertise protocol for X11 backend with GL renderer.
Changes in v2:
- Remove sync file wait fallbacks.
- Raise UNSUPPORTED_BUFFER error at commit if we have an acquire
fence, but the committed buffer is not a valid linux_dmabuf.
- Don't put buffers with in-fences on planes that don't support
in-fences.
- Don't advertise explicit sync protocol if backend does not
support explicit sync.
Signed-off-by: Alexandros Frantzis <alexandros.frantzis@collabora.com>
Introduce support for the zwp_linux_explicit_synchronization_unstable_v1
protocol with an implementation of the zwp_linux_explicit_synchronization_v1
interface.
Explicit synchronization provides a more versatile notification
mechanism for buffer readiness and availability, and can be used to
improve efficiency by integrating with related functionality in display
and graphics APIs.
In addition, the per-commit nature of the release events provided by
this protocol potentially offers a solution to a deficiency of the
wl_buffer.release event (see
https://gitlab.freedesktop.org/wayland/wayland/issues/46).
Support for this protocol depends on the capabilities of the backend, so
we don't register it by default but provide a function which each
backend will need to call. In this commit only the headless backend when
using the noop renderer supports this to enable testing.
Note that the zwp_surface_synchronization_v1 interface, which contains
the core functionality of the protocol, is not implemented in this
commit. Support for it will be added in future commits.
Changes in v7:
- Added some information in the commit message about the benefits of
the explicit sync protocol.
Changes in v6:
- Fall back to advertising minor version 1 of the explicit sync protocol,
although we support minor version 2 features, until the new
wayland-protocols version is released.
Changes in v5:
- Meson support.
- Advertise minor version 2 of the explicit sync protocol.
Changes in v4:
- Enable explicit sync support in the headless backend for all
renderers.
Changes in v3:
- Use wl_resource_get_version() instead of hardcoding version 1.
- Use updated protocol interface names.
- Use correct format specifier for resource id.
- Change test name to 'linux-explicit-synchronization.weston'
(s/_/-/g).
Changes in v2:
- Move implementation to separate file so protocol can be registered
on demand by backends.
- Register protocol in headless+noop backend for testing purposes.
Signed-off-by: Alexandros Frantzis <alexandros.frantzis@collabora.com>
Use the proper function to exit instead of the libwayland one, to allow main
handle_exit() to be called.
This is just to unify the exit paths.
Signed-off-by: Pekka Paalanen <pekka.paalanen@collabora.com>
The buffer-count test was added in
40c0c3f91e and removed in
4938f93f57, but the removal left around
the dependency to EGL headers in weston-test.c.
Removal of those unneeded includes allows us to drop the EGL dependency
completely from weston-test.c build.
For the Meson build this means that there are no dependency('egl')
directives anymore without the user friendly error message.
Signed-off-by: Pekka Paalanen <pq@iki.fi>
Meson is a build system, currently implemented in Python, with multiple
output backends, including Ninja and Make. The build file syntax is
clean and easy to read unlike autotools. In practise, configuring and
building with Meson and Ninja has been observed to be much faster than
with autotools. Also cross-building support is excellent.
More information at http://mesonbuild.com
Since moving to Meson requires some changes from users in any case, we
took this opportunity to revamp build options. Most of the build options
still exist, some have changed names or more, and a few have been
dropped. The option to choose the Cairo flavour is not implemented since
for the longest time the Cairo image backend has been the only
recommended one.
This Meson build should be fully functional and it installs everything
an all-enabled autotools build does. Installed pkg-config files have
some minor differences that should be insignificant. Building of some
developer documentation that was never installed with autotools is
missing.
It is expected that the autotools build system will be removed soon
after the next Weston release.
Signed-off-by: Daniel Stone <daniels@collabora.com>
Co-authored-by: Pekka Paalanen <pq@iki.fi>
Signed-off-by: Pekka Paalanen <pq@iki.fi>
No need to use the protocol directory prefix. This may even be necessary
for the Meson build.
Signed-off-by: Daniel Stone <daniels@collabora.com>
Extracted from the patch adding the Meson build system.
Signed-off-by: Pekka Paalanen <pq@iki.fi>
Collect the fallback definitions of static_assert() from desktop-shell
and the test shell, and move them to helpers.h. This allows code
throughout the tree to use static_assert() for build-time assertions,
where it is supported by the compiler.
As GCC goes out of its way to only add static_assert() when C11 has been
explicitly requested - which we don't do - make sure to use the more
widely available _Static_assert() if that is provided.
This will be used in future patches to ensure two array lengths don't go
out of sync.
Signed-off-by: Daniel Stone <daniels@collabora.com>
Reviewed-by: Pekka Paalanen <pekka.paalanen@collabora.co.uk>
Rename the IVI tests to be more consistent with the others, and invert
the naming of plugin/client to make it slightly more clear what's going
to happen. Handle the renaming by using wet_get_binary_path to rewrite
the local binaries.
As a side-effect, weston.ini ivi-shell-user-interface no longer needs to
be given as an absolute path.
Signed-off-by: Daniel Stone <daniels@collabora.com>
v2:
Call ivi-layout.ivi as ivi-layout-test-client.ivi to keep the same name
in both the file and the lookup, so that the module map does not need to
change the name.
Update code comments to reflect the new names.
Rename ivi_layout-test-plugin.c to ivi-layout-test-plugin.c.
Signed-off-by: Pekka Paalanen <pekka.paalanen@collabora.co.uk>
Reviewed-by: Daniel Stone <daniels@collabora.com>
Reviewed-by: Emre Ucan <eucan@de.adit-jv.com>
Reviewed-by: Emil Velikov <emil.velikov@collabora.com>
There are no users left.
Signed-off-by: Pekka Paalanen <pekka.paalanen@collabora.co.uk>
Reviewed-by: Daniel Stone <daniels@collabora.com>
Reviewed-by: Emre Ucan <eucan@de.adit-jv.com>
Rather than having a hardcoded dependency on the build-directory layout,
use an explicit module-map environment variable, which rewrites requests
for modules and helper/libexec binaries to specific paths.
Pekka: This will help with migration to Meson where setting up the paths
according to autotools would be painful and unnecessary.
Emre: This should also help setting up the test suite after a
cross-compile.
Pekka: A caveat here is that this patch makes it slightly easier to load
external backends by abusing the module map. External backends are
specifically not supported in libweston.
Signed-off-by: Daniel Stone <daniels@collabora.com>
v2:
Fixed ivi_layout-test-plugin.c:wet_module_init().
Do not change the lookup name of ivi-layout.ivi.
Improved documentation of weston_module_path_from_env() and made it cope
with map strings that a) do not end with a semicolon, and b) have
multiple consecutive semicolons.
Let WESTON_MODULE_MAP be printed into the test log so that it is easier
to run tests manually.
Reviewed-by: Daniel Stone <daniels@collabora.com>
Reviewed-by: Emre Ucan <eucan@de.adit-jv.com>
Suggested by Emil: Use a variable for strlen(name).
Signed-off-by: Pekka Paalanen <pekka.paalanen@collabora.co.uk>
Reviewed-by: Emil Velikov <emil.velikov@collabora.com>
Relay touch input events into libweston core through the
weston_touch_device, so that the core can tell which individual physical
device they come from.
This is necessary for supporting touchscreen calibration, where one
needs to process a single physical device at a time instead of the
aggregate of all touch devices on the weston_seat.
Signed-off-by: Pekka Paalanen <pekka.paalanen@collabora.co.uk>
v1 Tested-by: Matt Hoosier <matt.hoosier@gmail.com>
Reviewed-by: Peter Hutterer <peter.hutterer@who-t.net>
Introduce weston_touch_device for libweston core to track individual
touchscreen input devices. A weston_seat/weston_touch may be an
aggregation of several physical touchscreen input devices. Separating
the physical devices will be required for implementing touchscreen
calibration. One can only calibrate one device at a time, and we want to
make sure to handle the right one.
Both backends that support touch devices are updated to create
weston_touch_devices. Wayland-backend provides touch devices that cannot
be calibrated, because we have no access to raw touch coordinates from
the device - calibration is the responsibility of the parent display
server. Libinput backend provides touch devices that can be calibrated,
hence implementing the set and get calibration hooks.
Backends need to maintain an output pointer in any case, so we have a
get_output() hook instead of having to maintain an identical field in
weston_touch_device. The same justification applies to
get_calibration_head_name.
Also update the test plugin to manage weston_touch_device objects.
Co-developed by Louis-Francis and Pekka.
v2:
- Consistently use 'cal' instead of 'calb' or 'matrix'.
- change devpath into syspath
- update copyrights
Signed-off-by: Louis-Francis Ratté-Boulianne <lfrb@collabora.com>
Signed-off-by: Pekka Paalanen <pekka.paalanen@collabora.co.uk>
v1 Tested-by: Matt Hoosier <matt.hoosier@gmail.com>
Reviewed-by: Peter Hutterer <peter.hutterer@who-t.net>
Add test_seat_release() as the counterpart of test_seat_init() instead
of open-coding it. This helps adding more code to test_seat_release()
later.
Signed-off-by: Pekka Paalanen <pekka.paalanen@collabora.co.uk>
Reviewed-by: Peter Hutterer <peter.hutterer@who-t.net>
The user data of a wl_resource representing a wl_output protocol object
used to be a pointer to weston_output. Now that weston_output is being
split, wl_output more accurately refers to weston_head which is a single
monitor.
Change the wl_output user data to point to weston_head.
weston_output_from_resource() is replaced with
weston_head_from_resource().
This change is not strictly necessary, but architecturally it is the
right thing to do. In the future there might appear the need to refer to
a specific head of a cloned pair, for instance.
Signed-off-by: Pekka Paalanen <pekka.paalanen@collabora.co.uk>
v5 Reviewed-by: Derek Foreman <derekf@osg.samsung.com>
Reviewed-by: Ian Ray <ian.ray@ge.com>
Reviewed-by: Daniel Stone <daniels@collabora.com>
Acked-by: Derek Foreman <derekf@osg.samsung.com>
Implement the zwp_input_timestamps_manager_v1.get_touch_timestamps
request to subscribe to timestamp events for wl_touch resources. Ensure
that the request handling code can gracefully handle inert touch
resources.
Signed-off-by: Alexandros Frantzis <alexandros.frantzis@collabora.com>
Reviewed-by: Pekka Paalanen <pekka.paalanen@collabora.co.uk>
Implement the zwp_input_timestamps_manager_v1.get_pointer_timestamps
request to subscribe to timestamp events for wl_pointer resources.
Ensure that the request handling code can gracefully handle inert
pointer resources.
Signed-off-by: Alexandros Frantzis <alexandros.frantzis@collabora.com>
Reviewed-by: Pekka Paalanen <pekka.paalanen@collabora.co.uk>
Implement the zwp_input_timestamps_manager_v1.get_keyboard_timestamps
request to subscribe to timestamp events for wl_keyboard resources.
Ensure that the request handling code can gracefully handle inert
keyboard resources.
This commit introduces a few internal helper functions which will also
be useful in the implementation of the remaining
zwp_input_timestamps_manager_v1 requests.
Signed-off-by: Alexandros Frantzis <alexandros.frantzis@collabora.com>
Reviewed-by: Pekka Paalanen <pekka.paalanen@collabora.co.uk>
Introduce helper test code to implement the client side of the
input_timestamps_unstable_v1 protocol. This helper will be used in
upcoming commits to test the server side implementation of the protocol
in libweston.
The input_timestamps_unstable_v1 protocol was introduced in version 1.13
of wayland-protocols, so this commit updates the version dependency in
configure.ac accordingly.
Signed-off-by: Alexandros Frantzis <alexandros.frantzis@collabora.com>
Reviewed-by: Pekka Paalanen <pekka.paalanen@collabora.co.uk>
Add a helper function to check if two struct timespec values are equal.
This helper function will be used in upcoming commits that implement the
input_timestamps_unstable_v1 protocol.
Signed-off-by: Alexandros Frantzis <alexandros.frantzis@collabora.com>
Reviewed-by: Pekka Paalanen <pekka.paalanen@collabora.co.uk>
Add a test to check that we can destroy and create the test seat. Since
after test seat destruction the test client releases any associated
input resources, this test also checks that libweston properly handles
release requests for inert input resources.
Signed-off-by: Alexandros Frantzis <alexandros.frantzis@collabora.com>
Reviewed-by: Pekka Paalanen <pekka.paalanen@collabora.co.uk>
Use the weston-test-desktop-shell to run the devices tests, instead of
the currently used desktop-shell. The test desktop shell doesn't
interact with temporary globals (e.g. wl_seat), thus avoiding an
inherent race in the current wayland protocol when removing globals.
This will allow us to safely add tests which add/remove such globals in
upcoming commits.
Signed-off-by: Alexandros Frantzis <alexandros.frantzis@collabora.com>
Reviewed-by: Pekka Paalanen <pekka.paalanen@collabora.co.uk>
The current test client code waits for all wl_seat globals to arrive
before checking them and deciding which one is the test seat global to
use for the input object. Test code that needs to add/remove test seats
would have to call the client_set_input() function for any seat changes
to take effect. Although we could allow this by making
client_set_input() public, we would be exposing unecessary
implementation details.
This commit applies any seat changes immediately upon arrival of the
seat name, freeing test code from needing to call extra functions like
client_set_input(). To achieve this the call to input_data_devices() is
moved from client_set_input() to the seat name event handler.
This commit also moves the check that all seats have names to an
explicit test. To support this test, inputs corresponding to non-test
seats are not destroyed (unless their seat global is removed), as
was previously the case.
Signed-off-by: Alexandros Frantzis <alexandros.frantzis@collabora.com>
Reviewed-by: Pekka Paalanen <pekka.paalanen@collabora.co.uk>
The current test client code completely ignores removal of globals.
This commit updates the code to properly handle removal of globals in
general, and of seat globals in particular. This ensures that the test
client objects are in sync with the server and any relevant resources
are released accordingly.
This update will be used by upcoming tests to check that seat removal
and re-addition is working properly.
Signed-off-by: Alexandros Frantzis <alexandros.frantzis@collabora.com>
Reviewed-by: Pekka Paalanen <pekka.paalanen@collabora.co.uk>
ivi-shell tests load their own controller plugin
for testing purposes. Tests also uses the generated
weston-ivi.in config file, which causes weston to
load hmi-controller and its helper client.
Existence of hmi-controller and its helper client
confuses test plugins. Because they are creating
surfaces and layers which are not expected by
test plugins.
We can start ivi-shell tests without config file
to solve this problem. Then, weston will not load
hmi-controller plugin.
Reported-by: Pekka Paalanen <pekka.paalanen@collabora.co.uk>
Signed-off-by: Emre Ucan <eucan@de.adit-jv.com>
Reviewed-by: Pekka Paalanen <pekka.paalanen@collabora.co.uk>
Acked-by: Daniel Stone <daniels@collabora.com>
Instead of assuming the file prefix contains the path and filename
prefix, give these two items separately.
A NULL or empty string path may still be given to refer to the current
directory.
Signed-off-by: Aleksander Morgado <aleksander@aleksander.es>
Reviewed-by: Daniel Stone <daniels@collabora.com>
It is better to load ivi controller modules as a
generic weston module. Then, we do not need to
have a specific ivi way of loading modules.
Signed-off-by: Emre Ucan <eucan@de.adit-jv.com>
Reviewed-by: Pekka Paalanen <pekka.paalanen@collabora.co.uk>
Set the env var to override the system data directory so we can run
tests with uninstalled icons.
We don't yet use the code that checks this env var, so make distcheck
will still fail.
Signed-off-by: Derek Foreman <derekf@osg.samsung.com>
Acked-by: Daniel Stone <daniels@collabora.com>
Reviewed-by: Quentin Glidic <sardemff7+git@sardemff7.net>
Reviewed-by: Pekka Paalanen <pekka.paalanen@collabora.co.uk>
Support adding a test seat using the weston_test.device_add request.
This will be used in tests in upcoming commits where we will need to
re-add the seat after having it removed.
We only support one test seat at the moment, so this commit also
introduces checks to ensure the client doesn't try to create multiple
test seats or try to remove an already removed test seat.
Signed-off-by: Alexandros Frantzis <alexandros.frantzis@collabora.com>
Reviewed-by: Pekka Paalanen <pekka.paalanen@collabora.co.uk>
Add test to verify the server correctly emits pointer axis events. This
requires updating the weston-test protocol with a new request for
pointer axis events.
Signed-off-by: Alexandros Frantzis <alexandros.frantzis@collabora.com>
Reviewed-by: Pekka Paalanen <pekka.paalanen@collabora.co.uk>
Add test to verify that the server correctly sets the timestamps of
touch events. This requires updating the weston-test protocol with a new
request for touch events.
Signed-off-by: Alexandros Frantzis <alexandros.frantzis@collabora.com>
Reviewed-by: Pekka Paalanen <pekka.paalanen@collabora.co.uk>
Add test to verify that the server correctly sets the timestamps of
keyboard key events. This requires updating the weston-test protocol to
support passing key event timestamps.
simple_keyboard_test now uses the create_client_with_keyboard_focus()
helper function which changes the initial state of the surface to be
focused. This leads to one additional iteration of the test loop when
starting, during which the surface is deactivated, i.e., loses focus.
After this initial iteration the test continues as before.
Furthermore, simple_keyboard_test now uses the send_key() helper
function which performs a roundtrip internally. To account for this, the
client_roundtrip() function is now directly called in the loop only when
it is still required, i.e., when deactivating the surface.
Signed-off-by: Alexandros Frantzis <alexandros.frantzis@collabora.com>
Reviewed-by: Pekka Paalanen <pekka.paalanen@collabora.co.uk>
Enhance the existing pointer motion and button event tests to
additionally verify the event timestamps. This requires updating the
weston-test protocol to support passing motion and button event
timestamps.
Signed-off-by: Alexandros Frantzis <alexandros.frantzis@collabora.com>
Reviewed-by: Pekka Paalanen <pekka.paalanen@collabora.co.uk>
Add helper function to convert from struct timespec values to tv_sec_hi,
tv_sec_lo, tv_nsec triplets used for sending high-resolution timestamp
data over the wayland protocol. Replace existing conversion code with
the helper function.
Signed-off-by: Alexandros Frantzis <alexandros.frantzis@collabora.com>
Reviewed-by: Pekka Paalanen <pekka.paalanen@collabora.co.uk>
Add helper function to convert tv_sec_hi, tv_sec_lo, tv_nsec triplets,
used for sending high-resolution timestamp data over the wayland
protocol, to struct timespec values. Replace existing conversion code
with the helper function.
Signed-off-by: Alexandros Frantzis <alexandros.frantzis@collabora.com>
Reviewed-by: Pekka Paalanen <pekka.paalanen@collabora.co.uk>
Split pointer motion and pointer button tests so that each test case is
more focused and self-contained.
Signed-off-by: Alexandros Frantzis <alexandros.frantzis@collabora.com>
Reviewed-by: Pekka Paalanen <pekka.paalanen@collabora.co.uk>
Move wl_pointer tests from event-test.c to their own pointer-test.c
file. This move makes the test organization clearer and more consistent,
and will make addition of further pointer tests easier.
Signed-off-by: Alexandros Frantzis <alexandros.frantzis@collabora.com>
Reviewed-by: Pekka Paalanen <pekka.paalanen@collabora.co.uk>
This doesn't attach a buffer to the surface. This is needed for the
next commit, where we have a test case with a surface that doesn't
have a buffer attached.
Signed-off-by: Emilio Pozuelo Monfort <emilio.pozuelo@collabora.co.uk>
Reviewed-by: Pekka Paalanen <pekka.paalanen@collabora.co.uk>
Reviewed-by: Daniel Stone <daniels@collabora.com>
Ensure that the integer type used in expressions involving
multiplication with NSEC_PER_SEC is large enough to avoid overflows on
32-bit systems. In the expressions fixed by this patch a 64-bit type
(long long) is required.
Signed-off-by: Alexandros Frantzis <alexandros.frantzis@collabora.com>
Reviewed-by: Daniel Stone <daniels@collabora.com>
Without this attribute, the test macros were making Weston fail to
build with LTO enabled.
Signed-off-by: Markus Trippelsdorf <markus@trippelsdorf.de>
Signed-off-by: Emmanuel Gil Peyrot <emmanuel.peyrot@collabora.com>
Tested-by: Emmanuel Gil Peyrot <emmanuel.peyrot@collabora.com>
Reviewed-by: Daniel Stone <daniels@collabora.com>
This is a preparatory patch for the next one.
Signed-off-by: Emmanuel Gil Peyrot <emmanuel.peyrot@collabora.com>
Reviewed-by: Daniel Stone <daniels@collabora.com>
Change code related to key events to use struct timespec to represent
time.
This commit is part of a larger effort to transition the Weston codebase
to struct timespec.
Signed-off-by: Alexandros Frantzis <alexandros.frantzis@collabora.com>
Reviewed-by: Pekka Paalanen <pekka.paalanen@collabora.co.uk>
Change code related to button events to use struct timespec to represent
time.
This commit is part of a larger effort to transition the Weston codebase
to struct timespec.
Signed-off-by: Alexandros Frantzis <alexandros.frantzis@collabora.com>
Reviewed-by: Pekka Paalanen <pekka.paalanen@collabora.co.uk>
Change code related to motion events to use struct timespec to represent
time.
This commit is part of a larger effort to transition the Weston codebase
to struct timespec.
Signed-off-by: Alexandros Frantzis <alexandros.frantzis@collabora.com>
Reviewed-by: Pekka Paalanen <pekka.paalanen@collabora.co.uk>
Add helper functions to make it easy and less error-prone to convert
between values in various time units (nsec, usec, msec) and struct
timespec. These helpers are going to be used in the upcoming commits to
transition the Weston codebase to struct timespec.
Signed-off-by: Alexandros Frantzis <alexandros.frantzis@collabora.com>
Reviewed-by: Pekka Paalanen <pekka.paalanen@collabora.co.uk>
Add a helper function to check if a struct timespec is zero. This helper
will be used in the upcoming commits to transition the Weston codebase
to struct timespec.
Signed-off-by: Alexandros Frantzis <alexandros.frantzis@collabora.com>
Reviewed-by: Pekka Paalanen <pekka.paalanen@collabora.co.uk>
Alexandros Frantzis
Pekka Paalanen
Pekka Paalanen
Greg V
Daniel Stone
Pekka Paalanen
Louis-Francis Ratté-Boulianne
Emre Ucan
Aleksander Morgado
Derek Foreman
Emilio Pozuelo Monfort
Valery Kartel
Emmanuel Gil Peyrot