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let artwork, canvas, rect, _x, _y,  c, w, h, w2, h2, TWOPI, genetics, player, enemies, bullets, players, prevTime, nextTime, deltaTime, startTime, totalTime, isGameover, u, aPlayer, maxEnemies, generation = 1, isStarting = true;const init = function(){  maxEnemies = 7;  isGameover = false;  const oldCanvas = document.querySelector('#game');    if( oldCanvas )      oldCanvas.remove();    else      addEventsListener();  canvas = document.createElement('canvas');  canvas.id = "game";  canvas.width = w = 1366;  canvas.height = h = 768;  w2 = w/2;  h2 = h/2;  TWOPI = Math.PI * 2;  prevTime = nextTime = deltaTime = startTime = Date.now();  totalTime = 0;  c = canvas.getContext('2d');  c.font = "25px Arial";  c.textAlign = "center";  document.body.appendChild(canvas);  rect = canvas.getBoundingClientRect();  _x = w/rect.width;  _y = h/rect.height;  genetics = new Genetics();  genetics.createPopulation();  player = new Player();  enemies = genetics.population.slice();  bullets = Array();  players = [player, ...enemies];  if( isStarting ){    startScreen();  }else{    update();  }}
const update = function(){  nextTime = Date.now();  deltaTime = nextTime - prevTime;  totalTime += deltaTime;  for(let i = bullets.length-1; i >= 0; i--){    bullets[i].update();    if( bullets[i].isGone )      bullets.splice(i, 1) }
  for(let i = players.length-1; i >= 0 ; i--){    if( !players[i].isDead )      players[i].update(player); }
 draw();
  if( player.isDead ){    gameover()    return }
 let allDead = true;
  for(let i = 0; i < enemies.length; i++ ){    if( !enemies[i].isDead ){      allDead = false;      break;    } }
  if( allDead ){    endRound()    return  }  prevTime = nextTime;  u = requestAnimationFrame( update );}
const draw = function(){  c.clearRect(0, 0, w, h);  for(let i = 0; i < bullets.length; i++){    bullets[i].show(); }
  for(let i = 0; i < players.length; i++){    if( !players[i].isDead )      players[i].show();  }  c.textAlign = "start";  c.fillStyle = "black";  c.fillText("Generation: "+generation, 10, 30 )  c.textAlign = "center";}
const endRound = function(){  totalTime = (Date.now() - startTime) / 1000;  genetics.evolve();  enemies = genetics.population.slice();  players = [player, ...enemies];  startTime = Date.now();  generation += 1;  player.health = Math.min(10, player.health + player.health * 0.15)  update();}
const startScreen = function(){  c.clearRect(0,0,w,h);  c.drawImage(artwork, 0, 0, artwork.width, artwork.height, 0, 0, w, h);  c.fillColor = "black";  c.fillText("Click to Start", w-w2/2, h2 )}
const gameover = function(){  if(u) cancelAnimationFrame(u)
  generation = 1;  let i = 0;  const drawGameover = function(){    c.fillStyle = "rgba(0,0,0,"+(i += 0.01)+")";    c.fillRect(0,0,w,h);    c.fillStyle = "white";    c.fillText("You have failed the human race.", w2, h2-25); c.fillText("You should move to mars or something.", w2, h2+25);
    if( i <= 1 ){      requestAnimationFrame( drawGameover );    }else{      c.fillText("Click to try again.", w2, h2/2);      isGameover = true;    }  }  drawGameover();}
const addEventsListener = function(){  document.body.addEventListener('mousemove', e => {    player.lookAt(e.clientX * _x, e.clientY * _y);  });  document.body.addEventListener('keydown', e => {    e.preventDefault(); switch(e.keyCode){
 case 37 : case 65 :
 player.isMoving.left = true;
 break;
 case 38 : case 87 :
 player.isMoving.up = true;
 break;
 case 39 : case 68 :
 player.isMoving.right = true;
 break;
 case 40 : case 83 :
 player.isMoving.down = true;
 break; }
 });

 document.body.addEventListener('keyup', e => {
 e.preventDefault();
 switch(e.keyCode){
 case 37 : case 65 :
 player.isMoving.left = false;
 break;
 case 38 : case 87 :
 player.isMoving.up = false;
 break;
 case 39 : case 68 :
 player.isMoving.right = false;
 break;
 case 40 : case 83 :
 player.isMoving.down = false;
 break; }
 });

 document.body.addEventListener('mouseup', e => {
 e.preventDefault();
 player.isShooting = false;
 });
  document.body.addEventListener('mousedown', e => {    e.preventDefault();    if( isGameover ){ init();      return;    }    if( isStarting ){      isStarting = false;      update();      return;    }    player.isShooting = true;  });  window.onresize = _ => {    if(u)      cancelAnimationFrame(u)    isStarting = true; init();  }}aPlayer = document.createElement('audio');aPlayer.src = "sounds/shoot.mp3";artwork = new Image();artwork.src = "artwork.png";artwork.onload = _ => {  init();  if( /Android|webOS|iPhone|iPad|iPod|BlackBerry|IEMobile|Opera Mini/i.test(navigator.userAgent) ){    const control = new GuiControls();  }}