docs: Update the HACKING.backends file

The create_context() and ensure_context() sections should be more clear
on the role of the functions, and their eventual caveats, like being
called multiple times.
This commit is contained in:
Emmanuele Bassi 2010-03-03 18:17:15 +00:00
parent c3a942abde
commit dbe2acc2b1

View File

@ -95,11 +95,18 @@ can be overridden:
by Clutter. Clutter will call this function during the initialization
phase. A GL (or GLES) context must always be available after the
initialization, so that Cogl and Clutter can query it for capabilities.
This function might be called multiple times so if a context was
successfully created in a previous call, this function should
short-circuit early and return TRUE
ClutterBackend::ensure_context
-- This function is used to ensure that the backend drawing context
is made current for passed ClutterStage, using the backend-specific
API.
API. This function is called each time a new stage is going to
be painted. If the Stage is inside its destruction sequence this
function should either fall back the drawing context to a default
drawing surface or should unset the drawing surface from the
drawing context.
ClutterBackend::redraw
-- This function is used to draw the passed ClutterStage; the backend