queries/world_query

• C++

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  #include <world_query.h>
  #include <iostream>
   
  struct Position { 
      double x, y;
  };
   
  struct Velocity { 
      double x, y;
  };
   
  int main(int, char *[]) {
      flecs::world ecs;
   
      // Create a few test entities for a Position, Velocity query
      ecs.entity("e1")
          .set<Position>({10, 20})
          .set<Velocity>({1, 2});
   
      ecs.entity("e2")
          .set<Position>({10, 20})
          .set<Velocity>({3, 4});
   
      // This entity will not match as it does not have Position, Velocity
      ecs.entity("e3")
          .set<Position>({10, 20});
   
      // world::each is a quick way to run simple component queries.
      ecs.each([](flecs::entity e, Position& p, Velocity& v) {
          p.x += v.x;
          p.y += v.y;
          std::cout << e.name() << ": {" << p.x << ", " << p.y << "}\n";
      });
  }