In the iOS fest repo I added some simple occlusion culling which in certain scenarios (and on iOS generally for 2D form based applications) leads to performance improvements. The implementation is essentially contained the in the following change sets in rt-closed:


changeset: 16094:1b9a81911bce
user: rbair
date: Fri Apr 20 10:41:02 2012 -0700
summary: Added methods needed for Occlusion Culling

changeset: 16093:df4efae842f6
parent: 16044:9c45324db001
parent: 16092:228d0641053c
user: rbair
date: Fri Apr 20 10:04:59 2012 -0700
summary: Merged in Occlusion Culling


and this change set in rt:


changeset: 858:a105a2d7e324
parent: 820:d67e7b2ec253
parent: 857:0718976204bb
user: rbair
date: Fri Apr 20 10:03:40 2012 -0700
summary: Merged in the occlusion culling patch.

This should be reviewed by an expert in the dirty region code.