OpenRA/OpenRA — pull request #5540 by RoosterDragon (2014-06-04 00:54:39+00:00)
Title: Avoid redundancy in BeginFrame.

- Cache the old resolution, scroll and zoom in BeginFrame, and don't bother updating the viewport parameters again until they change.
- Pass around scroll as an int2 to reduce the number of back-and-forth casts.