Main edit: VectorRotator. Let fromCameraToWorld and other two functions to return pointer rather than void. Fix usage mistake in main.cpp by inputing numSamplingPoints (input was always 1 previously). After the fix, localization performance boosts and more stable with sampling by SAMPLING_GRID. SAMPLING_RANDOM's result is not stable, i.e. points converge but convergence varies even the camera doesn't move.