javascript game

main.js

window.onload = function() {
  var canvas = document.createElement('canvas');
  canvas.width = 640;
  canvas.height = 480;
  document.body.appendChild(canvas);
  var context = canvas.getContext('2d');

  var player = Object();
  var obstacles = [Object(), Object(), Object()];

  var init = function() {
    player.y = 0;
    player.fall = 0;
    player.velocity = 0;

    obstacles.some(function(obstacle, index) {
      obstacle.x = 640 + index * 300;
    });
  }

  init();
  var space = false;

  document.onkeydown = function() {
    if (event.keyCode == 32) space = true
  }
  document.onkeyup = function() {
    if (event.keyCode == 32) space = false
  }

  var game = function() {
    // ジャンプ可能 & ジャンプキー推した
    if(player.y == 0 && space) {
      player.fall = 20;
    }
    // 落ちる速度上昇
    player.fall -= 1.5;
    // playerを落とす
    player.y += player.fall;
    // 地面にめり込んだ？
    if(player.y < 0) {
      player.y = 0;
      player.fall = 0;
    }

    obstacles.some(function(obstacle, index) {
      obstacle.x -= 10;
      if(30 < obstacle.x + 40 &&
        player.y < 40 &&
        90 > obstacle.x &&
        player.y + 60 > 0) {
        init();
      }
      if(obstacle.x < -40) {
        obstacle.x = 700 + Math.random() * 500;
      }
    })

    context.clearRect(0, 0, canvas.width, canvas.height);
    context.fillStyle = 'rgb(0, 198, 0)';
    context.fillRect(0, 400, 640, 80);

    context.fillStyle = 'rgb(0, 0, 198)';
    context.fillRect(30, 340 - player.y, 60, 60);

    obstacles.some(function(obstacle, index) {
      context.fillStyle = 'rgb(198, 0, 0)';
      context.fillRect(obstacle.x, 360, 40, 40);
    });

    setTimeout(game, 50);
  }
  setTimeout(game, 50);
}