cpp-game-engine/engine/game_dispatch.cpp

//
//  game_dispatch.cpp
//  gameutils
//
//  Created by Sam Jaffe on 9/2/16.
//

#include <thread>

#include "game_dispatch.hpp"

#include "events.hpp"
#include "scene.hpp"

namespace engine {
  namespace {
    event::event_type mask( event::event_type t, bool pressed ) {
      return static_cast<event::event_type>( t | ( pressed ? event::PRESSED_MASK : event::RELEASED_MASK ) );
    }
  }
  
  game_dispatch::game_dispatch( )
  : screen_size( { 1920.f, 1080.f } )
  , minimum_frame_duration( engine::FPS60 )
  , scenes( )
  , current_timestamp( clock::now( ) )
  , curr_scene( ) {
    
  }
  
  game_dispatch::current_scene_info::current_scene_info( ) {
    
  }
  
  game_dispatch::current_scene_info::current_scene_info( scene * curr )
  : ptr( curr )
  , current_scene_id( ptr->id )
  , local_size( ptr->get_size( ) ) {
    
  }
  
  void game_dispatch::process_key_event( raw_key_t key, bool press ) {
    if ( ! curr_scene.is_keyboard_event ) return;
    auto const & binding = curr_scene.ptr->get_binding( );
    auto it = binding.find( key );
    if ( it == binding.end( ) ) return;

    curr_scene.ptr->handle_key_event( {
      it->second,
      mask( event::KEY_MASK, press )
    } );
  }
  
  void game_dispatch::process_mouse_event( math::vec2 mouse_pos, bool press ) {
    if ( ! curr_scene.is_mouse_event ) return;
    math::vec2 local_scene_position = mouse_pos * curr_scene.local_size / screen_size;

    curr_scene.ptr->handle_mouse_event( {
      local_scene_position,
      mask( event::MOUSE_MASK, press )
    } );
  }
  
  tick game_dispatch::get_tick( ) {
    timestamp now = clock::now( );
    return { now, now - current_timestamp };
  }
  
  tick game_dispatch::next_frame( ) {
    tick t = get_tick( );
    
    while ( t.since < minimum_frame_duration ) {
      std::this_thread::sleep_for( minimum_frame_duration - t.since );
      t = get_tick( );
    }
    
    current_timestamp = t.now;
    return t;
  }
  
  void game_dispatch::gameloop( ) try {
    while ( running ) { single_frame( next_frame( ) ); }
    cleanup_resources( );
    exit( EXIT_SUCCESS );
  } catch ( std::exception const & ex ) {
    // todo: logging
    exit( EXIT_FAILURE );
  }
  
  void game_dispatch::quit( ) {
    running = false;
  }
}