+ // Increase the patch size a bit; since patch spacing is not necessarily
+ // an integer number of pixels, and we don't use conservative rasterization,
+ // we could be missing the outer edges of the patch. And it seemingly helps
+ // a little bit in general to have some more candidates as well -- although
+ // this is measured without variational refinement, so it might be moot
+ // with it.
+ //
+ // Tihs maps [0.0,1.0] to [-0.25 to 1.25), ie. extends the patch by 25% in
+ // all directions.
+ vec2 grown_pos = (position * 1.5) - vec2(0.25, 0.25);