cpp-game-engine/engine/src/game_dispatch.cpp

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

#include <thread>

#include "game/engine/game_dispatch.hpp"

#include "game/engine/events.hpp"
#include "game/engine/scene.hpp"
#include "game/util/env.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(env::screen_size()),
        minimum_frame_duration(engine::fps::v60), 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->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->keys();
    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};
  }

  float 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 std::chrono::duration<float>(t.since).count();
  }

  void game_dispatch::update() { curr_scene.ptr->update(next_frame()); }

  void game_dispatch::render() { curr_scene.ptr->render(); }
}