Andreas Fabri wrote:
Hi Luke,
thank you for your explanations for the 45 degree case. You have a nice solution. I guess for the general case I have to read the BoostCon paper first.
andreas
Thank you for saying so. As requested, I haved added a test case for which CGAL fails to subversion https://svn.boost.org/svn/boost/sandbox/gtl/forcgal.cpp I appologize that the test case is rather large. Expected output is: $$$$$$$$$$$$ RANDOM TEST $$$$$$$$$$$$$$$$ Square BOXX size: 6000 ************************* CGAL error: precondition violation! Expr: compare_xy(cv1.right(), p) == LARGER && compare_xy(cv2.right(), p) == LARGER File: /nfs/ltdn/disks/tcad_lmg_db_exchange_01/CGAL-3.3.1/include/CGAL/Arr_segment_traits_2.h Line: 609 Explanation: terminate called after throwing an instance of 'CGAL::Precondition_exception' what(): CGAL ERROR: precondition violation! Expr: compare_xy(cv1.right(), p) == LARGER && compare_xy(cv2.right(), p) == LARGER File: /nfs/ltdn/disks/tcad_lmg_db_exchange_01/CGAL-3.3.1/include/CGAL/Arr_segment_traits_2.h Line: 609 Abort This assertion in CGAL code looked to me like some condition that should be ensured by CGAL itself and is an internal error rather than a precondition violation. My interpretation was that the wrong exception type was used. I could be wrong, however, and if you find there was in fact something wrong with the polygon I produced I will eagerly fix my algorithm. My intention was to implement a booleans algorithm with the weakest possible preconditions and the strongest possible postconditions. Thanks, Luke