[cgma-dev] copying iGeom entities in occ...

[shriwise]

Hi all,

I just ran into an interesting problem in CGM built with OCC. When an 
entity is copied, the original loses all user-applied tag information 
(or so it seems). I understand why a copy might not keep data from the 
original, but for the data to disappear from the original altogether 
seems like incorrect behaviour to me.


I wrote a test as an example of this below. The test fails on the red 
line. Any ideas as to why? I've tracked the number of tags on the entity 
and they seem to disappear in line 5804 of iGeom_CGMA.cc.

Any help or insight for this would be very appreciated! I'm close to 
finishing my updates to the iGeom interface and this seems to be the 
last piece of the puzzle.


bool tag_copied_ent_test(iGeom_Instance geom)
{

   int err;

   //create a tag
   iBase_TagHandle test_tag;
   std::string name("test_tag");
   iGeom_createTag(geom, &name[0], 1, iBase_INTEGER, &test_tag, &err, 
name.length());
   CHECK( "ERROR: could not create tag" );

   //create a test entity
   iBase_EntityHandle cyl;
   iGeom_createCylinder(geom, 5.0, 5.0, 0.0, &cyl, &err);
   CHECK( "ERROR: could not create the cylinder" );

   //set a value for this tag on the original
   int value = 6;
   iGeom_setIntData(geom, cyl, test_tag, value, &err);
   CHECK( "ERROR: could not set the tag data" );

   //create a copy
   iBase_EntityHandle copy;
   iGeom_copyEnt(geom, cyl, &copy, &err);
   CHECK( "ERROR: could not copy the entity" );

   //check to see if the tag is accessible
   int bytes;
   iGeom_getTagSizeBytes(geom, test_tag, &bytes, &err);
   CHECK( "ERROR: could not get the tag size" );

   if (bytes != sizeof(int)) return false;

   iGeom_getIntData(geom, cyl, test_tag, &check_value, &err);
   CHECK( "ERROR: could not get the tag data" );

   if (check_value != value) return false;

   //cleanup
   iGeom_destroyTag(geom, test_tag, 1, &err);
   CHECK( "ERROR: could not destroy tag" );

   iGeom_deleteEnt(geom, cyl, &err);
   CHECK( "ERROR: could not delete entity" );

   iGeom_deleteEnt(geom, copy, &err);
   CHECK( "ERROR: could not delete entity" );

   return true;
}

-- 
Patrick C. Shriwise
Research Assistant
University of Wisconsin - Madison
Engineering Research Building - Rm. 428
1500 Engineering Drive
Madison, WI 53706
(608) 446-8173

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