papercats/game.js

var Player;
if (!Player)
  throw new Error("Requires player.js");

var Grid;
if (!Grid)
  throw new Error("Requires grid.js");
  


/**
 * Provides requestAnimationFrame in a cross browser way.
 * @author paulirish / http://paulirish.com/
 */
window.requestAnimationFrame = function( /* function FrameRequestCallback */ callback, /* DOMElement Element */ element ) {
      window.setTimeout( callback, 1000 / 60 );
    };
if ( !window.requestAnimationFrame ) {
  window.requestAnimationFrame = ( function() {
    return window.webkitRequestAnimationFrame ||
    window.mozRequestAnimationFrame ||
    window.oRequestAnimationFrame ||
    window.msRequestAnimationFrame ||
    function( /* function FrameRequestCallback */ callback, /* DOMElement Element */ element ) {
      window.setTimeout( callback, 1000 / 60 );
    };
  })();
}


$(function() {
  var BORDER_WIDTH = 20;
  var GRID_SIZE = 200;
  var CELL_WIDTH = 30;
  var SPEED = 5;
  var SHADOW_OFFSET = 5;
  var MAX_FRAMES = 16;
  var DROP_HEIGHT = 16;
  var BOUNCE_FRAMES = 8;
  var DROP_SPEED = 2;
  var canvas = $("#main-ui")[0];
  var ctx = canvas.getContext('2d');

  var width = canvas.width = window.innerWidth - 20;
  var height = canvas.height = window.innerHeight - 20;
  
  var players = [];
  var animateOff = true;
  var animateGrid = new Grid(GRID_SIZE);
  var grid = new Grid(GRID_SIZE, function(row, col, before, after) {
    if (before === after || animateOff)
      return;
    animateGrid.set(row, col, {
      before: before,
      after: after,
      frame: 0
    });
  }); 
  
  //Load players.
  for (var p = 0; p < 9; p++)
  {
    //TODO: socket loading.
    players[p] = new Player(null, grid, p, getRandomInt(0, GRID_SIZE), getRandomInt(0, GRID_SIZE));
  }
  
  //Load grid.
  for (var r = 0; r < grid.size; r++)
  {
    for (var c = 0; c < grid.size; c++)
    {
      //TODO: load data.
      if (Math.random() > .9)
        grid.set(r, c, players[getRandomInt(0, players.length)]);
    }
  }
  animateOff = false;

  var frameCount = 0;
  var animateTo = [0, 0];
  var offset = [0, 0];
  
  //TODO: current player index
  var user = players[0];
  centerOnPlayer(user, offset);
  
  function update()
  {
    //Change grid offsets.
    for (var i = 0; i <= 1; i++)
    {
      if (animateTo[i] !== offset[i])
      {
        var delta = animateTo[i] - offset[i];
        var dir = Math.sign(delta);
        var mag = Math.min(SPEED, Math.abs(delta));
        offset[i] += dir * mag;
      }
    }
    
    
    //Move players.
    var dead = [];
    players = players.filter(function(val) {
      val.move();
      if (val.dead)
        dead.push(val);
      return !val.dead;
    });
    
    //Remove players with collisions.
    var removing = [];
    for (var i = 0; i < players.length; i++)
    {
      for (var j = i; j < players.length; j++)
      {
        
        //Remove those players when other players have hit their tail.
        if (!removing[j] && players[j].tail.hitsTail(players[i]))
          removing[j] = true;
        if (!removing[i] && players[i].tail.hitsTail(players[j]))
          removing[i] = true;
        
        //Remove players with collisons...
        if (i !== j && squaresIntersect(players[i].startX, players[j].startX) &&
          squaresIntersect(players[i].startY, players[j].startY))
        {
          //...if one player is own his own territory, the other is out.
          if (grid.get(players[i].row, players[i].col) === players[i])
            removing[j] = true;
          else if (grid.get(players[j].row, players[j].col) === players[j])
            removing[i] = true;
          else
          {
            //...otherwise, the one that sustains most of the collision will be removed.
            var areaI = area(players[i]);
            var areaJ = area(players[j]);
            
            if (areaI === areaJ)
              removing[i] = removing[j] = true;
            else if (areaI > areaJ)
              removing[i] = true;
            else
              removing[j] = true;
          }
        }
      }
    }
    
    players = players.filter(function(val, i) {
      if (removing[i])
      {
        dead.push(val);
        val.die();
      }
      return !removing[i];
    });
    
    dead.forEach(function(val) {
      console.log(val.name + " is dead");
    });
    for (var r = 0; r < grid.size; r++)
    {
      for (var c = 0; c < grid.size; c++)
      {
        if (dead.indexOf(grid.get(r, c)) !== -1)
          grid.set(r, c, null);
      }
    }
    
    //TODO: animate dead, and if this player is dead.
    centerOnPlayer(user, animateTo);
  }
  
  function centerOnPlayer(player, pos)
  {
    var xOff = Math.floor(player.posX - (width - CELL_WIDTH) / 2);
    var yOff = Math.floor(player.posY - (height - CELL_WIDTH) / 2);
    pos[0] = Math.max(Math.min(xOff, grid.size * CELL_WIDTH + BORDER_WIDTH * 2 - width), 0);
    pos[1] = Math.max(Math.min(yOff, grid.size * CELL_WIDTH + BORDER_WIDTH * 2 - height), 0);
  }
  
  function area(player)
  {
    var xDest = player.col * CELL_WIDTH;
    var yDest = player.row * CELL_WIDTH;
    
    if (player.startX === xDest)
      return Math.abs(player.startY - yDest);
    else
      return Math.abs(player.startX - xDest);
  }
  
  //Thanks to https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Math/random
  function getRandomInt(min, max) {
    min = Math.ceil(min);
    max = Math.floor(max);
    return Math.floor(Math.random() * (max - min)) + min;
  }
  
  function squaresIntersect(a, b)
  {
    if (a < b)
      return b < a + CELL_WIDTH;
    else
      return a < b + CELL_WIDTH;
  }
  
  function paintGridBorder() 
  {
    ctx.fillStyle = 'lightgray';
    var gridWidth = CELL_WIDTH * GRID_SIZE;
    
    ctx.fillRect(-BORDER_WIDTH, 0, BORDER_WIDTH, gridWidth);
    ctx.fillRect(-BORDER_WIDTH, -BORDER_WIDTH, gridWidth + BORDER_WIDTH * 2, BORDER_WIDTH);
    ctx.fillRect(gridWidth, 0, BORDER_WIDTH, gridWidth);
    ctx.fillRect(-BORDER_WIDTH, gridWidth, gridWidth + BORDER_WIDTH * 2, BORDER_WIDTH);
  }
  
  function paintGridLines()
  {
    ctx.fillStyle = 'lightgray';
    ctx.beginPath();
    for (var x = modRotate(-offset[0], CELL_WIDTH); x < width; x += CELL_WIDTH)
    {
      ctx.moveTo(x, 0);
      ctx.lineTo(x, height);
    }
    for (var y = modRotate(-offset[1], CELL_WIDTH); y < height; y+= CELL_WIDTH)
    {
      ctx.moveTo(0, y);
      ctx.lineTo(width, y);
    }
    ctx.stroke();
  }
  
  function modRotate(val, mod)
  {
    var res = val % mod;
    if (res >= 0)
      return res;
    else
      return mod + res;
  }
  
  function paintGrid()
  {
    ctx.translate(BORDER_WIDTH, BORDER_WIDTH);
    
    paintGridBorder();
    //paintGridLines();
    
    //Get viewing limits
    var minRow = Math.max(Math.floor((offset[1] - BORDER_WIDTH) / CELL_WIDTH), 0); 
    var minCol = Math.max(Math.floor((offset[0] - BORDER_WIDTH) / CELL_WIDTH), 0); 
    var maxRow = Math.min(Math.ceil((offset[1] + height) / CELL_WIDTH), grid.size); 
    var maxCol = Math.min(Math.ceil((offset[0] + width) / CELL_WIDTH), grid.size); 
      
    //Paint occupied areas. (and fading ones).
    for (var r = minRow; r < maxRow; r++)
    {
      for (var c = minCol; c < maxCol; c++)
      {
        var p = grid.get(r, c);
        var x = c * CELL_WIDTH, y = r * CELL_WIDTH, baseColor, shadowColor;
        
        var animateSpec = animateGrid.get(r, c);
        if (!animateOff && animateSpec)
        {
          if (animateSpec.before) //fading animation
          {
            var alpha = 1 - (animateSpec.frame / MAX_FRAMES);
            baseColor = animateSpec.before.baseColor.deriveAlpha(alpha);
            shadowColor = animateSpec.before.shadowColor.deriveAlpha(alpha);
          }
          else
            continue;
        } 
        else if (p)
        {
          baseColor = p.baseColor;
          shadowColor = p.shadowColor;
        }
        else //No animation nor is this player owned. 
          continue;
        
        if (!grid.isOutOfBounds(r + 1, c) && !grid.get(r + 1, c) && !animateGrid.get(r + 1, c))
        {
          ctx.fillStyle = shadowColor.rgbString();
          ctx.fillRect(x, y + CELL_WIDTH, CELL_WIDTH, SHADOW_OFFSET);
        }
        ctx.fillStyle = baseColor.rgbString();
        ctx.fillRect(x, y, CELL_WIDTH, CELL_WIDTH);
      }
    }
    
    if (animateOff)
      return;
    
    //Paint squares with drop in animation.
    for (var r = 0; r < grid.size; r++)
    {
      for (var c = 0; c < grid.size; c++)
      {
        animateSpec = animateGrid.get(r, c);
        x = c * CELL_WIDTH, y = r * CELL_WIDTH;
        
        if (animateSpec && !animateOff) 
        {
          var viewable = r >= minRow && r < maxRow && c >= minCol && c < maxCol;
          if (animateSpec.after && viewable)
          {
            //Bouncing the squares.
            var offsetBounce = 0;
            if (animateSpec.frame >= MAX_FRAMES - BOUNCE_FRAMES)
            {
              var bounce = animateSpec.frame - MAX_FRAMES + BOUNCE_FRAMES;
              var bounceHeight = BOUNCE_FRAMES / 2 * DROP_SPEED;
              if (bounce >= BOUNCE_FRAMES / 2)
                offsetBounce = bounceHeight - (bounce - BOUNCE_FRAMES / 2) * DROP_SPEED;
              else
                offsetBounce = bounce * DROP_SPEED;
            }
            else
              offsetBounce = DROP_HEIGHT - DROP_SPEED * animateSpec.frame;
            
            y -= offsetBounce;
            
            shadowColor = animateSpec.after.shadowColor;
            baseColor = animateSpec.after.baseColor.deriveLumination(-(offsetBounce / DROP_HEIGHT) * .1);
            
            ctx.fillStyle = shadowColor.rgbString();
            ctx.fillRect(x, y + SHADOW_OFFSET, CELL_WIDTH, CELL_WIDTH);
            ctx.fillStyle = baseColor.rgbString();
            ctx.fillRect(x, y, CELL_WIDTH, CELL_WIDTH);
          }
          
          animateSpec.frame++;
          if (animateSpec.frame >= MAX_FRAMES)
            animateGrid.set(r, c, null);
        }
      }
    }
  }
  
  
  var showedDead = false;
  function paintLoop()
  {
    ctx.fillStyle = 'whitesmoke';
    ctx.fillRect(0, 0, width, height);
    
    ctx.translate(-offset[0], -offset[1]);
    paintGrid();
    players.forEach(function (p) {
      p.render(ctx);
    });
    ctx.setTransform(1, 0, 0, 1, 0, 0); //Reset transform.
    
    if (user.dead && !showedDead)
    {
      showedDead = true;
      console.log("You died!");
      //return;
    }
    
    //TODO: sync each loop with server. (server will give frame count.)
    frameCount++;
    update();
    requestAnimationFrame(paintLoop);
  }
  paintLoop();
  
  
  //Event listeners
  $(document).keydown(function(e) {
    if (user.dead)
      return;
    var newHeading = -1;
    switch (e.which)
    {
      case 37: newHeading = 3; break; //LEFT
      case 38: newHeading = 0; break; //UP
      case 39: newHeading = 1; break; //RIGHT
      case 40: newHeading = 2; break; //DOWN
      default: return; //exit handler for other keys.
    }
    
    if (newHeading === user.currentHeading || ((newHeading % 2 === 0) ^ 
      (user.currentHeading % 2 === 0)))
    {
      //TODO: notify server.
      user.heading = newHeading;
    }
    e.preventDefault();
  });
});