贪吃蛇游戏是经典手机游戏，既简单又耐玩。通过控制蛇头方向吃蛋，使得蛇变长，从而获得积分。在诺基亚时代，风靡整个手机界，今天我们来看看另类的，如何使用php来实现贪吃蛇小游戏

废话不多说，代码奉上：

control.php

<!DOCTYPE html>
<html>
  <head>
    <meta charset="utf-8"/>
  </head>
  <body>
     <a href="control.php?a=up">上<a/>       <?session_start(); echo $_SESSION["count"];?>分<br/>
    <a href="control.php?a=left">左<a/> <a href="control.php?a=right">右<a/><br/>
     <a href="control.php?a=down">下<a/>
    <?
       
      switch($_GET["a"]){
        case "up";
          $_SESSION["con"]="up";
        break;
        case "down":
          $_SESSION["con"]="down";
        break;
        case "left":
          $_SESSION["con"]="left";
        break;
        case "right":
          $_SESSION["con"]="right";
        break;
      }
    ?>
  </body>
</html>

main.php

<!DOCTYPE html>
<html>
  <head>
    <meta charset="utf-9"/>
    <meta http-equiv="refresh" content="0.5"/>
  </head>
  <frameset rows="95,*" border="1" noresize >
    <frame src="control.php" name="top"/>
    <frame src="./tcs.php" name="menu"/>
  </frameset>
</html>

tcs.php

<?php
  session_start();
  $_SESSION["ud"];
  $_SESSION["lr"];  
  $im = imagecreatetruecolor(300,300);
  $blue = imagecolorallocate($im,0,0,255);
  $red = imagecolorallocate($im,255,0,0);
  $c1 = imagecolorallocate($im,200,200,200);
  imagefill($im,0,0,$c1);
  if(!isset($_SESSION["a"])&&!isset($_SESSION["b"])){
    $_SESSION["a"] =rand(0,290);
    $_SESSION["b"] =rand(0,290);
  }
  if(isset($_SESSION["a"])&&isset($_SESSION["b"])){
    imagerectangle($im,$_SESSION["a"],$_SESSION["b"],$_SESSION["a"]+10,$_SESSION["b"]+10,$red); 
  }
  if(abs(($_SESSION["lr"]-$_SESSION["a"]))<=5&&abs($_SESSION["ud"]-$_SESSION["b"])<=5){
    unset($_SESSION["a"]);
    unset($_SESSION["b"]);
    $_SESSION["count"]++;
  }
  switch($_SESSION["con"]){
    case "up";
      if($_SESSION["ud"]>10)
        $_SESSION["ud"]-=10;
      else
        $_SESSION["ud"]=0;
    break;
    case "down":
      if($_SESSION["ud"]<=280)
        $_SESSION["ud"]+=10;
      else
        $_SESSION["ud"]=290;
    break;
    case "left":
      if($_SESSION["lr"]>10)
        $_SESSION["lr"]-=10;
      else
        $_SESSION["lr"]=0;
    break;
    case "right":
      if($_SESSION["lr"]<=280)
        $_SESSION["lr"]+=10;
      else
        $_SESSION["lr"]=290;
    break;
  }
  for($i=0;$i<=$_SESSION["count"];$i++){
    switch($_SESSION["con"]){
      case "up":
        $_SESSION["udnext"] = $_SESSION["ud"]+10*$i;
        imagerectangle($im,$_SESSION["lr"],$_SESSION["udnext"],$_SESSION["lr"]+10,$_SESSION["udnext"]+10,$blue);
        // imagerectangle($im,$_SESSION["lr"],$_SESSION["udtime"][time()-$i],$_SESSION["lr"]+10,$_SESSION["udtime"][time()-$i]+10,$blue);
      break;
      case "down":
        $_SESSION["udnext"] = $_SESSION["ud"]-10*$i;
        imagerectangle($im,$_SESSION["lr"],$_SESSION["udnext"],$_SESSION["lr"]+10,$_SESSION["udnext"]+10,$blue);
        // imagerectangle($im,$_SESSION["lr"],$_SESSION["udtime"][time()+$i],$_SESSION["lr"]+10,$_SESSION["udtime"][time()+$i]+10,$blue);
      break;
      case "left":
        $_SESSION["lrnext"] = $_SESSION["lr"]+10*$i;
        imagerectangle($im,$_SESSION["lrnext"],$_SESSION["ud"],$_SESSION["lrnext"]+10,$_SESSION["ud"]+10,$blue);
        // imagerectangle($im,$_SESSION["lrtime"][time()-$i],$_SESSION["ud"],$_SESSION["lrtime"][time()-$i]+10,$_SESSION["ud"]+10,$blue);
      break;
      case "right":
        $_SESSION["lrnext"] = $_SESSION["lr"]-10*$i;
        imagerectangle($im,$_SESSION["lrnext"],$_SESSION["ud"],$_SESSION["lrnext"]+10,$_SESSION["ud"]+10,$blue);
        // imagerectangle($im,$_SESSION["lrtime"][time()+$i],$_SESSION["ud"],$_SESSION["lrtime"][time()+$i]+10,$_SESSION["ud"]+10,$blue);
      break;
    }
    //imagerectangle($im,$_SESSION["lr"],$_SESSION["ud"],$_SESSION["lr"]+10,$_SESSION["ud"]+10,$blue);
  }
  header("Content-Type: image/jpeg");
  imagejpeg($im);
  imagedestroy($im);  
?>