<?php
 
###########################################################################
##  Copyright (C) Wizardry and Steamworks 2015 - License: CC BY 2.0      ##
###########################################################################
## This is a script that uses Corrade's "getterrainheight" command in    ##
## order to genereate a red-channel height-map of the terrain without    ##
## the need to be an estate / region owner. Essentially this script can  ##
## be used to give an overview of the terrain height for any region.     ##
###########################################################################

###########################################################################
##                            CONFIGURATION                              ##
###########################################################################

# Set this to the name of the group.
$GROUP = '[Wizardry and Steamworks]:Support';
# Set this to the group password.
$PASSWORD = 'gerbileum';
# Set this to Corrade's HTTP Server URL.
$URL = 'http://corrade.internal:8080';
 
###########################################################################
##                               INTERNALS                               ##
###########################################################################

###########################################################################
##  Copyright (C) Wizardry and Steamworks 2015 - License: CC BY 2.0      ##
###########################################################################
function wasKeyValueGet($key, $data) {
    return array_reduce(
        explode(
            "&", 
            $data
        ),
        function($o, $p) {
            $x = explode("=", $p);
            return array_shift($x) != $o ? $o : array_shift($x);
        },
        $key
    );
}
 
###########################################################################
##  Copyright (C) Wizardry and Steamworks 2015 - License: CC BY 2.0      ##
###########################################################################
function mapValueToRange($value, $xMin, $xMax, $yMin, $yMax) {
    return $yMin + (
        (
            $yMax - $yMin
        ) 
        *
        (
            $value - $xMin
        )
        /
        (
            $xMax - $xMin
        )
    );
}
 
# This constructs the command as an array of key-value pairs.
$params = array(
    'command' => 'getterrainheight',
    'group' => $GROUP,
    'entity' => 'region',
    'password' => $PASSWORD
);
 
# We now escape each key and value: this is very important, because the 
# data we send to Corrade may contain the '&' or '=' characters (we don't 
# in this example though but this will not hurt anyone).
array_walk($params,
 function(&$value, $key) {
     $value = rawurlencode($key)."=".rawurlencode($value);
 }
);
$postvars = implode('&', $params);
 
# Set the options, send the request and then display the outcome
if (!($curl = curl_init())) {
    echo "Could not initialise CURL".PHP_EOL;
}
 
curl_setopt($curl, CURLOPT_URL, $URL);
curl_setopt($curl, CURLOPT_RETURNTRANSFER, true);
curl_setopt($curl, CURLOPT_POST, true);
curl_setopt($curl, CURLOPT_POSTFIELDS, $postvars);
$return = curl_exec($curl);
curl_close($curl);

$success = urldecode(
    wasKeyValueGet(
        "success", 
        $return
    )
);

// Unable to get the region heights?
if($success == 'False') return -1;

$map = str_getcsv(
    urldecode(
        wasKeyValueGet(
            "data", 
            $return
        )
    )
);

$max = max($map);
 
$im = imagecreatetruecolor(256, 256);
 
foreach(range(0, 255) as $x) {
    foreach(range(0, 255) as $y) {
        $red = mapValueToRange(
            $map[256 * $x + $y], 
            0,
            $max,
            0,
            256
        );
        imagesetpixel(
            $im,
            $x,
            256-$y,
            imagecolorallocate(
                $im,
                $red,
                0,
                0
            )
        );
    }
}

/* Uncomment to return Base64 data.
 * ob_start();
 * imagepng($im);
 * $png = ob_get_contents();
 * imagedestroy($im);
 * ob_end_clean();
 * echo base64_encode($png); 
 */

/* Just display the image. */
header('Content-Type: image/png');
imagepng($im);

?>