<?php

define('_indexroot', '../');
define('_header', '');
require _indexroot."require/load.php";


_checkGD("jpg", true);


$imgw = 65;
$imgh = 22;
$img = imagecreate($imgw, $imgh);
if(isset($_GET['n']) and isset($_SESSION[_sessionprefix.'captcha_code'][(int)$_GET['n']])) {
list($code, $drawn) = $_SESSION[_sessionprefix.'captcha_code'][(int)$_GET['n']];
if($drawn) die;
$_SESSION[_sessionprefix.'captcha_code'][(int)$_GET['n']][1] = true;
} else die;




class linear_perspective
{

var $cam_location = array('x' => -30, 'y' => 0, 'z' => -250);
var $cam_rotation = array('x' => -1, 'y' => 0, 'z' => 0);
var $viewer_position = array('x' => 450, 'y' => -500, 'z' => -80);

function getProjection($point)
{
$translation = array();
$projection = array();

$translation['x'] = cos($this->cam_rotation['y']) * (sin($this->cam_rotation['z']) * ($point['y'] - $this->cam_location['y']) + cos($this->cam_rotation['z']) * ($point['x'] - $this->cam_location['x'])) - sin($this->cam_rotation['y']) * ($point['z'] - $this->cam_location['z']);
$translation['y'] = sin($this->cam_rotation['x']) * (cos($this->cam_rotation['y']) * ($point['z'] - $this->cam_location['z']) + sin($this->cam_rotation['y']) * (sin($this->cam_rotation['z']) * ($point['y'] - $this->cam_location['y']) + cos($this->cam_rotation['z']) * ($point['x'] - $this->cam_location['x']))) + cos($this->cam_rotation['z']) * (cos($this->cam_rotation['z']) * ($point['y'] - $this->cam_location['y']) - sin($this->cam_rotation['z']) * ($point['x'] - $this->cam_location['x']));
$translation['z'] = cos($this->cam_rotation['x']) * (cos($this->cam_rotation['y']) * ($point['z'] - $this->cam_location['z']) + sin($this->cam_rotation['y']) * (sin($this->cam_rotation['z']) * ($point['y'] - $this->cam_location['y']) + cos($this->cam_rotation['z']) * ($point['x'] - $this->cam_location['x']))) - sin($this->cam_rotation['z']) * (cos($this->cam_rotation['z']) * ($point['y'] - $this->cam_location['y']) - sin($this->cam_rotation['z']) * ($point['x'] - $this->cam_location['x']));

$projection['x'] = ($translation['x'] - $this->viewer_position['x']) * ($this->viewer_position['z'] / $translation['z']);
$projection['y'] = ($translation['y'] - $this->viewer_position['y']) * ($this->viewer_position['z'] / $translation['z']);

return $projection;
}

}

function imagelightnessat($img, $x, $y)
{
if(!is_resource($img)) return 0.0;

$c = @imagecolorat($img, $x, $y);
if($c === false) return false;

if(imageistruecolor($img)) {
$red = ($c >> 16) & 0xFF;
$green = ($c >> 8) & 0xFF;
$blue = $c & 0xFF;
} else {
$i = imagecolorsforindex($img, $c);
$red = $i['red'];
$green = $i['green'];
$blue = $i['blue'];
}

$m = min($red, $green, $blue);
$n = max($red, $green, $blue);
$lightness = (double)(($m + $n) / 510.0);
return ($lightness);
}

$perspective = new linear_perspective;


$matrix_dim = array('x' => 85, 'y' => 30);
$captcha_dim = array('x' => 410, 'y' => 120);
$distance = array('x' => 1, 'y' => 1, 'z' => 1);
$metric = array('x' => 10, 'y' => 25, 'z' => 5);
$offset = array('x' => 198, 'y' => -60);


$matrix = imagecreatetruecolor($matrix_dim['x'], $matrix_dim['y']);
$black = imagecolorexact($matrix, 0, 0, 0);
$white = imagecolorexact($matrix, 255, 255, 255);
$gray = imagecolorexact($matrix, 200, 200, 200);
imagefill($matrix, 0, 0, $white);


for($i = 0; $i < 300; ++$i) imagesetpixel($matrix, mt_rand(5, ($matrix_dim['x'] - 6)), mt_rand(5, ($matrix_dim['y'] - 6)), $gray);


imagefttext($matrix, 19, 0, 4, 25, $black, dirname(__file__).'/cimage.ttf', $code);


if(function_exists('imagerotate')) $matrix = imagerotate($matrix, mt_rand(-1, 1), $white);


$point = array();
for($x = 0; $x < $matrix_dim['x']; $x++) {
for($y = 0; $y < $matrix_dim['y']; $y++) {
$lightness = imagelightnessat($matrix, $x, $y);
$point[$x][$y] = $perspective->getProjection(array('x' => $x * $metric['x'] + $distance['x'], 'y' => $lightness * $metric['y'] + $distance['y'], 'z' => ($matrix_dim['y'] - $y) * $metric['z'] + $distance['z']));
}
}
imagedestroy($matrix);


$captcha = imagecreatetruecolor($captcha_dim['x'], $captcha_dim['y']);
if(_template_dark) {
$black = imagecolorexact($captcha, 255, 255, 255);
$white = imagecolorexact($captcha, 0, 0, 0);
} else {
$black = imagecolorexact($captcha, 0, 0, 0);
$white = imagecolorexact($captcha, 255, 255, 255);
}
imagefill($captcha, 0, 0, $white);


if(function_exists('imageantialias')) imageantialias($captcha, true);
for($x = 1; $x < $matrix_dim['x']; $x++)
for($y = 1; $y < $matrix_dim['y']; $y++) imageline($captcha, -$point[$x - 1][$y - 1]['x'] + $offset['x'], -$point[$x - 1][$y - 1]['y'] + $offset['y'], -$point[$x][$y]['x'] + $offset['x'], -$point[$x][$y]['y'] + $offset['y'], $black);





$width = 160;
$height = floor($width / ($captcha_dim['x'] / $captcha_dim['y']));
$rcaptcha = imagecreatetruecolor($width, $height);
imagecopyresampled($rcaptcha, $captcha, 0, 0, 0, 0, $width, $height, $captcha_dim['x'], $captcha_dim['y']);
header('Content-Type: image/png');
imagepng($rcaptcha);