Metal: use staging buffer for updating non-dynamic buffers

For non-dynamic (i.e. GPU-resident) buffers, onUpdateData() uses a
staging buffer rather than map() and unmap(). In addition, map() and
unmap() do nothing for non-dynamic buffers.

Also removes fOffset member, as it was never anything but 0.

Change-Id: I8bcd36c10c14d21395693686696462cca79a0e70
Reviewed-by: Greg Daniel <>
Commit-Queue: Jim Van Verth <>
5 files changed