relationships/exclusive_relations

• C

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  #include <exclusive_relations.h>
  #include <stdio.h>
   
  int main(int argc, char *argv[]) {
      ecs_world_t *ecs = ecs_init_w_args(argc, argv);
   
      ECS_TAG(ecs, Platoon);
   
      // Register Platoon as exclusive relationship. This ensures that an entity
      // can only belong to a single Platoon.
      ecs_add_id(ecs, Platoon, EcsExclusive);
   
      // Create two platoons
      ecs_entity_t platoon_1 = ecs_new(ecs);
      ecs_entity_t platoon_2 = ecs_new(ecs);
   
      // Create a unit
      ecs_entity_t unit = ecs_new(ecs);
   
      // Add unit to platoon 1
      ecs_add_pair(ecs, unit, Platoon, platoon_1);
   
      // Log platoon of unit
      printf("Unit in platoon 1: %s\n", 
          ecs_has_pair(ecs, unit, Platoon, platoon_1) ? "true" : "false");
      printf("Unit in platoon 2: %s\n\n", 
          ecs_has_pair(ecs, unit, Platoon, platoon_2) ? "true" : "false");
   
      // Add unit to platoon 2. Because Platoon is an exclusive relationship, this
      // both removes (Platoon, platoon_1) and adds (Platoon, platoon_2) in a
      // single operation.
      ecs_add_pair(ecs, unit, Platoon, platoon_2);
   
      printf("Unit in platoon 1: %s\n", 
          ecs_has_pair(ecs, unit, Platoon, platoon_1) ? "true" : "false");
      printf("Unit in platoon 2: %s\n", 
          ecs_has_pair(ecs, unit, Platoon, platoon_2) ? "true" : "false");
   
      // Output:
      //  Unit in platoon 1: true
      //  Unit in platoon 2: false
      //  
      //  Unit in platoon 1: false
      //  Unit in platoon 2: true
   
      return ecs_fini(ecs);
  }

• C++

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  #include <exclusive_relations.h>
  #include <iostream>
   
  // Type for Platoon relationship
  struct Platoon { };
   
  int main(int, char*[]) {
      flecs::world ecs;
   
      // Register Platoon as exclusive relationship. This ensures that an entity
      // can only belong to a single Platoon.
      ecs.component<Platoon>()
          .add(flecs::Exclusive);
   
      // Create two platoons
      flecs::entity platoon_1 = ecs.entity();
      flecs::entity platoon_2 = ecs.entity();
   
      // Create a unit
      flecs::entity unit = ecs.entity();
   
      // Add unit to platoon 1
      unit.add<Platoon>(platoon_1);
   
      // Log platoon of unit
      std::cout << "Unit in platoon 1: " << 
          (unit.has<Platoon>(platoon_1) ? "true" : "false") << "\n";
      std::cout << "Unit in platoon 2: " << 
          (unit.has<Platoon>(platoon_2) ? "true" : "false") << "\n\n";
   
      // Add unit to platoon 2. Because Platoon is an exclusive relationship, this
      // both removes (Platoon, platoon_1) and adds (Platoon, platoon_2) in a
      // single operation.
      unit.add<Platoon>(platoon_2);
   
      std::cout << "Unit in platoon 1: " << 
          (unit.has<Platoon>(platoon_1) ? "true" : "false") << "\n";
      std::cout << "Unit in platoon 2: " << 
          (unit.has<Platoon>(platoon_2) ? "true" : "false") << "\n";
   
      // Output:
      //  Unit in platoon 1: true
      //  Unit in platoon 2: false
      //  
      //  Unit in platoon 1: false
      //  Unit in platoon 2: true
  }