docs: Update the backend HACKING file

Clarify the Backend::create_context() vfunc role, and the
Stage::realize() vfunc with regards to creating the GL/GLES
context.
This commit is contained in:
Emmanuele Bassi 2010-02-12 11:38:47 +00:00
parent 44818a4827
commit 34c7611407

View File

@ -90,12 +90,11 @@ can be overridden:
from the GL or GLES implementation, plus the eventual backend-specific from the GL or GLES implementation, plus the eventual backend-specific
features. features.
ClutterBackend::get_display_size
-- Use this function to retrieve the size of the display.
ClutterBackend::create_context ClutterBackend::create_context
-- This function is used to create the drawing context to be used -- This function is used to create the drawing context to be used
by Clutter. 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.
ClutterBackend::ensure_context ClutterBackend::ensure_context
-- This function is used to ensure that the backend drawing context -- This function is used to ensure that the backend drawing context
@ -140,8 +139,9 @@ ClutterStage actor using the ClutterStageWindow implementation.
In the ::realize virtual function the stage implementation should: In the ::realize virtual function the stage implementation should:
- create a new native window handle - create a new native window handle
- if the backend doesn't have a drawing context (either GL or GLES), - ensure that there is a GL (or GLES) context
create one and pass it to the backend - make sure that the native window handle is compatible with
the GL (or GLES) context
The return value should be TRUE if the stage implementation was successfully The return value should be TRUE if the stage implementation was successfully
realized, and FALSE otherwise. realized, and FALSE otherwise.