ios - Accessing individual objects that all have the same categoryBitMask -

i have several game world objects player needs interact individually upon physicsbody.categorybitmask contacting them. instead of using separate categorybitmasks each individual object (object count surpasses categorybitmask's limit, 32) use 1 categorybitmask , gave objects individual names. here's how looks in code:

-(void)createcollisionareas {     if (_tilemap)     {         tmxobjectgroup *group = [_tilemap groupnamed:@"contactzone"]; //layer's name.          //province gateway.         nsdictionary *singularobject = [group objectnamed:@"msgdifferentprovince"];         if (singularobject)         {             cgfloat x = [singularobject[@"x"] floatvalue];             cgfloat y = [singularobject[@"y"] floatvalue];             cgfloat w = [singularobject[@"width"] floatvalue];             cgfloat h = [singularobject[@"height"] floatvalue];              skspritenode *object = [skspritenode spritenodewithcolor:[skcolor redcolor] size:cgsizemake(w, h)];             object.name = @"provincegateway";             object.position = cgpointmake(x + w/2, y + h/2);              object.physicsbody = [skphysicsbody bodywithrectangleofsize:cgsizemake(w, h)];              object.physicsbody.categorybitmask       = terraincategory;             object.physicsbody.contacttestbitmask    = playercategory;             object.physicsbody.collisionbitmask      = 0;             object.physicsbody.dynamic = no;             object.physicsbody.friction = 0;             object.hidden = yes;              [_backgroundlayer addchild:object];         }          /*more code written below. lazy copy & paste all*/ }  -(void)didbegincontact:(skphysicscontact *)contact {     skphysicsbody *firstbody, *secondbody; //create 2 placeholder reference's contacting objects.      if (contact.bodya.categorybitmask < contact.bodyb.categorybitmask) //if bodya has smallest of 2 bits...     {         firstbody   = contact.bodya; //...it firstbody reference [smallest of 2 (category) bits.].         secondbody  = contact.bodyb; //...and bodyb secondbody reference [largest of 2 bits.].     }     else //this reverse of above code (just in case know what's what).     {         firstbody = contact.bodyb;         secondbody = contact.bodya;     }       /**boundary contacts*/     if ((firstbody.categorybitmask == nogocategory) && (secondbody.categorybitmask == playercategory))     {         //boundary contacted player.         if ([_backgroundlayer childnodewithname:@"bounds"])         {             nslog(@"player contacted map bounds.");         }         if ([_backgroundlayer childnodewithname:@"nogo"])         {             nslog(@"player can't go further.");         }         if ([_backgroundlayer childnodewithname:@"provincegateway"])         {             nslog(@"another province ahead. can't go further.");         }         if ([_backgroundlayer childnodewithname:@"slope"])         {             nslog(@"player contacted slope.");         } } 

the problem is, in didbegincontact method, when player contacts object code gets executed. code objects player hasn't contacted yet. means if statements, such if ([_backgroundlayer childnodewithname:@"slope"]), not complete. can tell me how write out if statements individual object contact? following if statement, inside didbegincontact, doesn't work either:

if ([_player intersectsnode:[_backgroundlayer childnodewithname:@"slope"]]) 

your if statements checking if child exists, seems do. think want check if collision node has name looking for, change:

if ([_backgroundlayer childnodewithname:@"bounds"]) 

to:

if ([firstbody.node.name isequaltostring:@"bounds"])