wayland_zwp_linux_surface_synchronization_v1_t

per-surface explicit synchronization support

Synopsis

#include <wayland-client-protocol-unstable.hpp>

Inherits wayland::proxy_t.

Public Types

enum class wrapper_type { standard, display, foreign, proxy_wrapper }

void set_acquire_fence (int fd)
set the acquire fence
zwp_linux_buffer_release_v1_t get_release ()
release fence for last-attached buffer
uint32_t get_id () const
Get the id of a proxy object.
std::string get_class () const
Get the interface name (class) of a proxy object.
uint32_t get_version () const
Get the protocol object version of a proxy object.
wrapper_type get_wrapper_type () const
Get the type of a proxy object.
void set_queue (event_queue_t queue)
Assign a proxy to an event queue.
wl_proxy * c_ptr () const
Get a pointer to the underlying C struct.
bool proxy_has_object () const
Check whether this wrapper actually wraps an object.
operator bool () const
Check whether this wrapper actually wraps an object.
bool operator== (const proxy_t &right) const
Check whether two wrappers refer to the same object.
bool operator!= (const proxy_t &right) const
Check whether two wrappers refer to different objects.
void proxy_release ()
Release the wrapped object (if any), making this an empty wrapper.

Static Public Attributes

static constexpr std::uint32_t set_acquire_fence_since_version = 1
Minimum protocol version required for the set_acquire_fence function.
static constexpr std::uint32_t get_release_since_version = 1
Minimum protocol version required for the get_release function.

Detailed Description

per-surface explicit synchronization support

This object implements per-surface explicit synchronization.

Synchronization refers to co-ordination of pipelined operations performed on buffers. Most GPU clients will schedule an asynchronous operation to render to the buffer, then immediately send the buffer to the compositor to be attached to a surface.

In implicit synchronization, ensuring that the rendering operation is complete before the compositor displays the buffer is an implementation detail handled by either the kernel or userspace graphics driver.

By contrast, in explicit synchronization, dma_fence objects mark when the asynchronous operations are complete. When submitting a buffer, the client provides an acquire fence which will be waited on before the compositor accesses the buffer. The Wayland server, through a zwp_linux_buffer_release_v1 object, will inform the client with an event which may be accompanied by a release fence, when the compositor will no longer access the buffer contents due to the specific commit that requested the release event.

Each surface can be associated with only one object of this interface at any time.

In version 1 of this interface, explicit synchronization is only guaranteed to be supported for buffers created with any version of the wp_linux_dmabuf buffer factory. Version 2 additionally guarantees explicit synchronization support for opaque EGL buffers, which is a type of platform specific buffers described in the EGL_WL_bind_wayland_display extension. Compositors are free to support explicit synchronization for additional buffer types.

Definition at line 2247 of file wayland-client-protocol-unstable.hpp.

Member Enumeration Documentation

enum class wayland::proxy_t::wrapper_type [strong], [inherited]

Underlying wl_proxy type and properties of a proxy_t that affect construction, destruction, and event handling

Enumerator

standard: C pointer is a standard type compatible with wl_proxy*. Events are dispatched and it is destructed when the proxy_t is destructed. User data is set.
display: C pointer is a wl_display*. No events are dispatched, wl_display_disconnect is called when the proxy_t is destructed. User data is set.
foreign: C pointer is a standard type compatible with wl_proxy*, but another library owns it and it should not be touched in a way that could affect the operation of the other library. No events are dispatched, wl_proxy_destroy is not called when the proxy_t is destructed, user data is not touched. Consequently, there is no reference counting for the proxy_t. Lifetime of such wrappers should preferably be short to minimize the chance that the owning library decides to destroy the wl_proxy.
proxy_wrapper: C pointer is a wl_proxy* that was constructed with wl_proxy_create_wrapper. No events are dispatched, wl_proxy_wrapper_destroy is called when the proxy_t is destroyed. Reference counting is active. A reference to the proxy_t creating this proxy wrapper is held to extend its lifetime until after the proxy wrapper is destroyed.

Definition at line 116 of file wayland-client.hpp.

Member Function Documentation

wl_proxy * wayland::proxy_t::c_ptr () const [inherited]

Get a pointer to the underlying C struct.

Returns: The underlying wl_proxy wrapped by this proxy_t if it exists, otherwise an exception is thrown

std::string wayland::proxy_t::get_class () const [inherited]

Get the interface name (class) of a proxy object.

Returns: The interface name of the object associated with the proxy

uint32_t wayland::proxy_t::get_id () const [inherited]

Get the id of a proxy object.

Returns: The id the object associated with the proxy

zwp_linux_buffer_release_v1_t zwp_linux_surface_synchronization_v1_t::get_release ()

release fence for last-attached buffer

Returns: new zwp_linux_buffer_release_v1 object

Create a listener for the release of the buffer attached by the client with wl_surface.attach. See zwp_linux_buffer_release_v1 documentation for more information.

The release object is double-buffered state, and will be associated with the buffer that is attached to the surface at wl_surface.commit time.

If a zwp_linux_buffer_release_v1 object has already been requested for the surface in the same commit cycle, a DUPLICATE_RELEASE error is raised.

If the associated wl_surface was destroyed, a NO_SURFACE error is raised.

If at surface commit time there is no buffer attached, a NO_BUFFER error is raised.

Definition at line 5617 of file wayland-client-protocol-unstable.cpp.

uint32_t wayland::proxy_t::get_version () const [inherited]

Get the protocol object version of a proxy object. Gets the protocol object version of a proxy object, or 0 if the proxy was created with unversioned API.

A returned value of 0 means that no version information is available, so the caller must make safe assumptions about the object's real version.

display_t will always return version 0.

Returns: The protocol object version of the proxy or 0

wrapper_type wayland::proxy_t::get_wrapper_type () const [inline], [inherited]

Get the type of a proxy object.

Definition at line 302 of file wayland-client.hpp.

wayland::proxy_t::operator bool () const [inherited]

Check whether this wrapper actually wraps an object.

Returns: true if there is an underlying object, false if this wrapper is empty

bool wayland::proxy_t::operator!= (const proxy_t & right) const [inherited]

Check whether two wrappers refer to different objects.

bool wayland::proxy_t::operator== (const proxy_t & right) const [inherited]

Check whether two wrappers refer to the same object.

bool wayland::proxy_t::proxy_has_object () const [inherited]

Check whether this wrapper actually wraps an object.

Returns: true if there is an underlying object, false if this wrapper is empty

void wayland::proxy_t::proxy_release () [inherited]

Release the wrapped object (if any), making this an empty wrapper. Note that display_t instances cannot be released this way. Attempts to do so are ignored.

Examples foreign_display.cpp.

void zwp_linux_surface_synchronization_v1_t::set_acquire_fence (int fd)

set the acquire fence

Parameters: fd acquire fence fd

Set the acquire fence that must be signaled before the compositor may sample from the buffer attached with wl_surface.attach. The fence is a dma_fence kernel object.

The acquire fence is double-buffered state, and will be applied on the next wl_surface.commit request for the associated surface. Thus, it applies only to the buffer that is attached to the surface at commit time.

If the provided fd is not a valid dma_fence fd, then an INVALID_FENCE error is raised.

If a fence has already been attached during the same commit cycle, a DUPLICATE_FENCE error is raised.

If the associated wl_surface was destroyed, a NO_SURFACE error is raised.

If at surface commit time the attached buffer does not support explicit synchronization, an UNSUPPORTED_BUFFER error is raised.

If at surface commit time there is no buffer attached, a NO_BUFFER error is raised.

Definition at line 5611 of file wayland-client-protocol-unstable.cpp.

void wayland::proxy_t::set_queue (event_queue_t queue) [inherited]

Assign a proxy to an event queue.

Parameters: queue The event queue that will handle this proxy

Assign proxy to event queue. Events coming from proxy will be queued in queue instead of the display's main queue.

See also: display_t::dispatch_queue().

Examples proxy_wrapper.cpp.