bit0 set (1): specified points are relative to the OC tree reference frame, otherwise they are relative to the world reference frame
bit1 set (2): the color array contains one RGB triple per point, and the tag array contains one value per point. Otherwise it the color array contains a single RGB triple, and the tag array contains a single value.
pts: a pointer to the voxel positions specified as X/Y/Z coordinates
ptCnt: the number of point coordinates contained in pts
color: a pointer to one or several RGB triples, specifying the red, green and blue color components (0-255). Can be nullptr.
tag: a pointer to one or several uint32 values, which are user-defined values. Can be nullptr, and should be nullptr if color is nullptr.
reserved: reserved for future extensions. Set to nullptr