<?php
require_once("/usr/local/lib/php/20100525/phpchartdir.php");

# The x and y coordinates of the grid
$dataX = array(0, 0.1, 0.2, 0.3, 0.4, 0.5, 0.6, 0.7, 0.8, 0.9, 1.0);
$dataY = array(0, 0.1, 0.2, 0.3, 0.4, 0.5, 0.6, 0.7, 0.8, 0.9, 1.0);

# The values at the grid points. In this example, we will compute the values using
# the formula z = sin((x - 0.5) * 2 * pi) * sin((y - 0.5) * 2 * pi)
$dataZ = array_pad(array(), count($dataX) * count($dataY), 0);
for($yIndex = 0; $yIndex < count($dataY); ++$yIndex) {
    $y = ($dataY[$yIndex] - 0.5) * 2 * 3.1416;
    for($xIndex = 0; $xIndex < count($dataX); ++$xIndex) {
        $x = ($dataX[$xIndex] - 0.5) * 2 * 3.1416;
        $dataZ[$yIndex * count($dataX) + $xIndex] = sin($x) * sin($y);
    }
}

# the perspective level
$perspective = (int)($_REQUEST["img"]) * 12;

# Create a SurfaceChart object of size 360 x 360 pixels, with white (ffffff)
# background and grey (888888) border.
$c = new SurfaceChart(360, 360, 0xffffff, 0x888888);

# Set the perspective level
$c->setPerspective($perspective);
$c->addTitle("Perspective = $perspective");

# Set the center of the plot region at (195, 165), and set width x depth x height to
# 200 x 200 x 150 pixels
$c->setPlotRegion(195, 165, 200, 200, 150);

# Set the plot region wall thichness to 5 pixels
$c->setWallThickness(5);

# Set the elevation and rotation angles to 30 and 30 degrees
$c->setViewAngle(30, 30);

# Set the data to use to plot the chart
$c->setData($dataX, $dataY, $dataZ);

# Spline interpolate data to a 40 x 40 grid for a smooth surface
$c->setInterpolation(40, 40);

# Use smooth gradient coloring.
$c->colorAxis->setColorGradient();

# Output the chart
header("Content-type: image/jpeg");
print($c->makeChart2(JPG));
?>
