cpp-game-engine/engine/src/fps_counter.cxx

//
//  fps_counter.cxx
//  engine
//
//  Created by Sam Jaffe on 5/24/19.
//  Copyright © 2019 Sam Jaffe. All rights reserved.
//

#include "game/engine/fps_counter.hpp"

#include <json/value.h>
#include <unordered_map>

#include "game/engine/serial.hpp"
#include "game/engine/text_engine.hpp"
#include "game/graphics/object.hpp"
#include "game/graphics/renderer.hpp"

using namespace engine;

fps_counter::fps_counter(std::shared_ptr<text_engine> text_engine,
                         std::size_t precision)
    : digits_(precision), magnitude_(std::pow(10, digits_)),
      text_engine_(text_engine), glyphs_() {}

fps_counter::~fps_counter() {}

void fps_counter::render(graphics::renderer & renderer) const {
  for (auto & obj : glyphs()) {
    renderer.draw(obj);
  }
}

std::string fps_counter::fps(env::clock::duration const & since) const {
  auto fps = magnitude_ * env::clock::duration::period::den / since.count();
  std::string fps_str = std::to_string(fps);
  fps_str.insert(fps_str.size() - digits_, ".");
  return fps_str;
}

void fps_counter::set_frame_step(env::clock::duration const & since) {
  if (++counter_ != change_after_) { return; }
  counter_ = 0;
  text_engine_->create_text_cells(glyphs_,
                                  {{5.f, 780.f}, {10.f, 20.f}, fps(since)});
}