rejacobson / noah

A c++ component based entity management system.

////////////////////////////////////////////////////////
// Example Usage
//
// Note: The Entity System uses the namespace `noah`.  I 
// couldn't think of a wicked-awesome name for it so I 
// just used my son's name.  Maybe he'll be flattered 
// when he grows up.
////////////////////////////////////////////////////////

// Create an Entity System
noah::EntitySystem entity_system;

// Load some Component Systems into it
// Note the different label on the render system.  This is so the RenderComponentSystem can be
// updated separately from the rest of the systems.
entity_system.RegisterComponentSystem( new PositionComponentSystem(), "integration" );
entity_system.RegisterComponentSystem( new PhysicsComponentSystem(), "integration" );
entity_system.RegisterComponentSystem( new RenderComponentSystem(), "render" );

// The GameState is an arbitrary struct that can be used to pass data from the game loop to the
// Component Systems.  Add anything you want to it.  I have it carry over the current time in the
// loop and a pointer to the World object that I use.
GameState game_state;

// Create an entity to add components to
noah::Entity *e = entity_system.NewEntity();

entity_system.AddComponent( e, new PositionComponent(position_x, position_y) );
entity_system.AddComponent( e, new PhysicsComponent(velocity_x, velocity_y) );
entity_system.AddComponent( e, new RenderComponent("assets/sprite.png") );

entity_system.InitializeEntity( e, game_state );

// In the game loop
while ( game_is_running )
{
  // Updates the Position and Physics components
  entity_system.Update( "integration", game_state );

  // Updates the Render component
  entity_system.Update( "render", game_state );
}