Spell out exactly when a client may re-use a wl_buffer or its backing storage. Mention the optimization for GL-compositor with wl_shm-clients.
Signed-off-by: Pekka Paalanen <[email protected]> --- protocol/wayland.xml | 18 +++++++++++++++++- 1 files changed, 17 insertions(+), 1 deletions(-) diff --git a/protocol/wayland.xml b/protocol/wayland.xml index 740fb43..8214852 100644 --- a/protocol/wayland.xml +++ b/protocol/wayland.xml @@ -231,12 +231,28 @@ <request name="destroy" type="destructor"> <description summary="destroy a buffer"> Destroy a buffer. This will invalidate the object id. + + For possible side-effects to a surface, see wl_surface.attach. </description> </request> <event name="release"> <description summary="compositor releases buffer"> - Sent when an attached buffer is no longer used by the compositor. + Sent when this wl_buffer is no longer used by the compositor. + + If a client does not get a release event before the frame callback + requested in the same wl_surface.commit that attaches this wl_buffer + to a surface, then the client may assume, that the compositor will + be using this wl_buffer until the client attaches another wl_buffer. + Therefore the client will need a second wl_buffer to update the + surface contents again. + + Otherwise, if a release event arrives before the frame callback, the + client is immediately free to re-use the buffer and its backing + storage, and does not necessarily need a second buffer. Typically + this is possible, when the compositor maintains a copy of the + wl_surface contents, e.g. as a GL texture. This is an important + optimization for GL(ES) compositors with wl_shm clients. </description> </event> </interface> -- 1.7.8.6 _______________________________________________ wayland-devel mailing list [email protected] http://lists.freedesktop.org/mailman/listinfo/wayland-devel
