UBSAN: undefined behaviour in refine_loop.h

[zarquon42b]

OK, here is a definitive one: https://github.com/cnr-isti-vclab/vcglib/blob/master/vcg/complex/algorithms/refine_loop.h#L106 (and some following lines) You get a negative index for k < 3. My current patch looks like this: https://github.com/zarquon42b/Rvcg/blob/develop/src/vcglib/patches/16_refine_loop_ubsan.patch If you think this is viable, I can issue a PR.