<?php
define('DPI', 75);
define('OBS_DIST', DPI*12);
define('EYE_SEP', (int)DPI*2.5);
define('SEP_FACTOR', 0.55);
define('MAX_SCENE_HEIGHT', 255);
define('MIN_SCENE_HEIGHT', 0);
define('MAX_DEPTH', OBS_DIST);
define('MIN_DEPTH', (int)((SEP_FACTOR*MAX_DEPTH*OBS_DIST)/((1-SEP_FACTOR)*MAX_DEPTH+OBS_DIST)));
define('HEIGHT_SCALE', 2);
/* Init Random Number Generator */
srand(time());
$filename = "depthmap.png";
$depth_img = imagecreatefrompng($filename);
if(!$depth_img) die ("Error -- could not load depth image ($filename)!");
$img_width = imagesx($depth_img);
$img_height = imagesy($depth_img);
/* Create the image used in the stereogram */
$stereo_img = imagecreate($img_width, $img_height);
if(!$stereo_img) die("Error -- could not allocate stereo image!");
/* Initialize the colors that will be used in the image */
for($i = 0; $i < 256; $i++) {
if(isset($_POST['bw'])) {
$rnd_color = rand(0,255);
$colors[] = imagecolorallocate($stereo_img,
$rnd_color,
$rnd_color,
$rnd_color);
} else {
$colors[] = imagecolorallocate($stereo_img,
rand(0,255),
rand(0,255),
rand(0,255));
}
}
/* Load the img array with the random graphics data */
for($y = 0; $y < $img_height; $y++) {
for($x = 0; $x < $img_width; $x++) {
//$buffer[$x][$y] = $colors[rand(0,255)];
$temp = imagecolorsforindex($depth_img,imagecolorat($depth_img, $x, $y));
/* Get the current blue element */
$depth_color = $temp['blue'];
$height = $depth_color/HEIGHT_SCALE;
$height = ($height > MAX_SCENE_HEIGHT) ? MAX_SCENE_HEIGHT : $height;
$height = ($height < MIN_SCENE_HEIGHT) ? MIN_SCENE_HEIGHT : $height;
$feature_z = MAX_DEPTH-$height*(MAX_DEPTH-MIN_DEPTH)/256;
$sep = (int)((float)(EYE_SEP*$feature_z)/($feature_z+OBS_DIST));
$left_px = (int)$x-($sep/2);
$right_px = (int)$x+($sep/2);
if(($left_px >= 0) && ($right_px < $img_width)) {
if(!isset($buffer[$left_px][$y]))
$buffer[$left_px][$y] = $colors[rand(1,255)];
$buffer[$right_px][$y] = $buffer[$left_px][$y];
}
}
for($x = 0; $x < $img_width;$x++)
if(!isset($buffer[$x][$y]))
$buffer[$x][$y] = $colors[rand(1,255)];
}
/* Output PNG File */
for($y = 0; $y < $img_height; $y++) {
for($x = 0; $x < $img_width; $x++) {
imagesetpixel($stereo_img,$x, $y, $buffer[$x][$y]);
}
}
header("Content-type: image/png");
$black = imagecolorclosest($stereo_img, 0,0,0);
$white = imagecolorclosest($stereo_img, 0xff, 0xff, 0xff);
imagefilledrectangle($stereo_img, 0, $img_height-20, $img_width, $img_height, $black);
imagestring($stereo_img, 1, 5, $img_height-10, "Made at http://www.coggeshall.org/stereogram.php", $white);
imagepng($stereo_img);
?>
