entities/emplace

• C++

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  #include <emplace.h>
  #include <iostream>
   
  // The emplace method constructs a component directly in the storage vs. a 
  // regular set, which moves the value into an already constructed value in the
  // storage. This reduces the overhead of creating a new component.
  //
  // Components that do not have a default constructor need to be created with
  // emplace, as they can't be constructed automatically by flecs.
   
  struct NoDefaultCtor {
      NoDefaultCtor(double x_, double y_) : x(x_), y(y_) { }
   
      double x, y;
  };
   
  int main(int, char *[]) {
      flecs::world ecs;
   
      flecs::entity e = ecs.entity()
          .emplace<NoDefaultCtor>(10.0, 20.0);
   
      const NoDefaultCtor& c = e.get<NoDefaultCtor>();
      std::cout << "{" << c.x << ", " << c.y << "}" << "\n";
   
      // Output
      //  {10, 20}
  }