systems/startup_system

• C

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  #include <startup_system.h>
  #include <stdio.h>
   
  // Startup systems are systems registered with the EcsOnStart phase, and are
  // only ran during the first frame. Just like with regular phases, custom phases
  // can depend on the EcsOnStart phase (see custom_phases example). Phases that 
  // depend on EcsOnStart are also only ran during the first frame.
  //
  // Other than that, startup systems behave just like regular systems (they can
  // match components, can introduce merge points), with as only exception that
  // they are guaranteed to always run on the main thread. 
   
  void Startup(ecs_iter_t *it) {
      printf("%s\n", ecs_get_name(it->stage, it->system));
  }
   
  void Update(ecs_iter_t *it) {
      printf("%s\n", ecs_get_name(it->stage, it->system));
  }
   
  int main(int argc, char *argv[]) {
      ecs_world_t *ecs = ecs_init_w_args(argc, argv);
   
      // Startup system
      ECS_SYSTEM(ecs, Startup, EcsOnStart, 0);
   
      // Regular system
      ECS_SYSTEM(ecs, Update, EcsOnUpdate, 0);
   
      // First frame. This runs both the Startup and Update systems
      ecs_progress(ecs, 0.0f);
   
      // Second frame. This runs only the Update system
      ecs_progress(ecs, 0.0f);
   
      return ecs_fini(ecs);
   
      // Output
      //   Startup
      //   Update
      //   Update
  }

• C++

  View on GitHub

  #include <startup_system.h>
  #include <iostream>
   
  // Startup systems are systems registered with the EcsOnStart phase, and are
  // only ran during the first frame. Just like with regular phases, custom phases
  // can depend on the EcsOnStart phase (see custom_phases example). Phases that 
  // depend on EcsOnStart are also only ran during the first frame.
  //
  // Other than that, startup systems behave just like regular systems (they can
  // match components, can introduce merge points), with as only exception that
  // they are guaranteed to always run on the main thread. 
   
  int main(int, char *[]) {
      flecs::world ecs;
   
      // Startup system
      ecs.system("Startup")
          .kind(flecs::OnStart)
          .run([](flecs::iter& it) {
              std::cout << it.system().name() << "\n";
          });
   
      // Regular system
      ecs.system("Update")
          .run([](flecs::iter& it) {
              std::cout << it.system().name() << "\n";
          });
   
      // First frame. This runs both the Startup and Update systems
      ecs.progress();
   
      // Second frame. This runs only the Update system
      ecs.progress();
   
      // Output
      //   Startup
      //   Update
      //   Update
  }