Detect subpixel aliasing
Detect subpixel aliasing

Using the ratio between the average luma over the 3x3 neighborhood
minus the center luma and the max-min range, detect sub pixel aliasing
(single pixels of different luma), and compute an alternative UV offset
based on thus ratio.


Former-commit-id: 6b9ffaaf2473baecae8d00cdf5222bac485c2fe4
kosua20/GL_Template,kosua20/GL_Template