When a pipeline is added to the cache, a normal copy would previously be
made to use as the key in the hash table. This copy keeps a reference
to the real pipeline which means all of the resources it contains are
retained forever, even if they aren't necessary to generate the hash.
This patch changes it to create a trimmed down copy that only has the
state necessary to generate the hash. A new function called
_cogl_pipeline_deep_copy is added which makes a new pipeline that is
directly a child of the root pipeline. It then copies over the
pertinent state from the original pipeline. The pipeline state is
copied using the existing _cogl_pipeline_copy_differences function.
There was no equivalent function for the layer state so I have added
one.
That way the pipeline key doesn't have the texture data state and it
doesn't hold a reference to the original pipeline so it should be much
cheaper to keep around.
Reviewed-by: Robert Bragg <robert@linux.intel.com>
(cherry picked from commit e27e01c1215e7e7c7c0183ded11dd769bb112c5c)
20657d6245