structs to paint struct (might be useful for vertex paint too in the
future)
Cavity masking now has a curve control. The control will set the amount
of masking for positive cavity ("pointness") or negative cavity
("cavity") with x axis being the amount of cavity and 0.0 = full cavity,
1.0 = full pointness, 0.5 = no cavity and the y axis being the amount of
alpha.
f7e131a6ac