diff options
| author | Pekka Paalanen <ppaalanen@gmail.com> | 2012-10-10 12:47:50 +0300 |
|---|---|---|
| committer | Kristian Høgsberg <krh@bitplanet.net> | 2012-10-10 22:01:17 -0400 |
| commit | e09ac6450bc7dd2ae99acb9cc40b722a78ba69f4 (patch) | |
| tree | 7799fc4f23316751de28fcb853b47762f3ae108f | |
| parent | a4fd9e6583c47e9b997fff09dc32de1fc96f3b07 (diff) | |
protocol: elaborate on wl_buffer
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 <ppaalanen@gmail.com>
| -rw-r--r-- | protocol/wayland.xml | 18 |
1 files changed, 17 insertions, 1 deletions
diff --git a/protocol/wayland.xml b/protocol/wayland.xml index 61bf268..1903d1c 100644 --- a/protocol/wayland.xml +++ b/protocol/wayland.xml @@ -236,12 +236,28 @@ <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> |