16 total mask positions rather than like 150. This
should (1) cut back on video memory leakage, and
(2) reduce the probability of client lag due to drawing
dynamic textures all the time, after it's had a little
time to "warm up".
Resize base texture down to 16x first, so mask works
as expected. Some textures may be blurred, but
we're more concerned with getting the overal color
right more than showing actual patterns.
