import 'dart:html';
import 'package:browserloop/game/Game.dart';
import 'package:browserloop/game/LoopExample.dart';

/// The Variable Timestep Loop.
///
/// Perhaps one of the most widely used loops
/// in games for many years. Many game frameworks
/// make use of a loop similar to this.
class VariableTimestep implements LoopExample {
  Game game;
  num id;
  Stopwatch elapsed = new Stopwatch();

  VariableTimestep(Game this.game);

  void eventloop(num time) {
    int dt = elapsed.elapsedMilliseconds;
    game.update(dt);
    game.draw();
    elapsed.reset();

    id = window.requestAnimationFrame(eventloop);
  }

  // Starting and stopping the loop for the example page
  void stop() {
    elapsed.stop();
    window.cancelAnimationFrame(id);
  }

  void start() {
    elapsed.start();
    elapsed.reset();
    window.requestAnimationFrame(eventloop);
  }
}