Dimetric SVG creation

dimetric.php

<?php
// Create Dimetric SVG image
// Diametric is a parallel projection similar to isometric (30 degrees x 30 degrees grid) which is unequal (15 degrees x 60 degrees).

// To make a unit square, starting at (0,0), on the SVG canvas (Y axis flipped) as the closest point and going clockwise,
// the other points are (-cos(15), -sin(15)), (-cos(15)+cos(60), -sin(15)-sin(60)), (cos(60), -sin(60))
// or, (-0.965925826289068, -0.258819045102521), (-0.465925826289068, -1.12484444888696), (0.50, -0.866025403784439) 

$unit_square = new Polygon(
	new Point(0,0),
	new Point(-1*cos(pi()/12), -1*sin(pi()/12)),
	new Point(-1*cos(pi()/12)+cos(pi()/3), -1*sin(pi()/12)-sin(pi()/3)),
	new Point(cos(pi()/3), -1*sin(pi()/3))
);

$left_face = new Polygon(
	new Point(0.01,-0.1), // Cheat right and up to hide any rounding error gap
	new Point(-1*cos(pi()/12), -1*sin(pi()/12)),
	new Point(-1*cos(pi()/12), -1*sin(pi()/12)+1),
	new Point(0.01,1) // Cheat right
);
$right_face = new Polygon(
	new Point(0,-0.1), // Cheat up
	new Point(0,1),
	new Point(cos(pi()/3), -1*sin(pi()/3)+1),
	new Point(cos(pi()/3), -1*sin(pi()/3))
);

$global_scale = 21; // How many pixels is one square?
$global_origin_x = 300;
$global_origin_y = 300;

$unit_square = $unit_square->scale($global_scale);
$left_face = $left_face->scale($global_scale);
$right_face = $right_face->scale($global_scale);

// Create a scene
$blocks = array(
	//array(1,1,0,1,2),
	array(2,2,2,2,2, 2,1,1,1,2, 2,1,1,1,2, 2,1,1,1,2, 2,2,2,2,2),
	array(0,0,0,0,3, 0,1,1,1,0, 0,0,0,1,0, 0,1,1,1,0),
	array(0,0,0,0,0, 0,1,1,1,0, 0,0,0,1,0, 0,1,1,1,0),
	array(0,0,0,0,0, 0,1,1,1,0, 0,1,0,1,0, 0,1,1,1,0),
	array(0,0,0,0,0, 0,1,1,1,0, 0,1,0,1,0, 0,1,1,1,0),
	array(0,0,0,0,0, 0,1,1,1,0, 0,1,0,1,0, 0,1,1,1,0),
	array(1,1,1,1,1, 1,1,1,1,1, 1,1,0,1,1, 1,1,1,1,1, 1,1,1,1,1),
	array(1,0,1,0,1, 0,0,0,0,0, 1,0,0,0,1, 0,0,0,0,0, 1,0,1,0,1),
);
$global_row_size = 5; // How many blocks in a row?

/*
list($sample_top, $sample_left, $sample_right) = multiTranslate($global_origin_x, $global_origin_y, array($unit_square, $left_face, $right_face));

$extra = $sample_right->translate(0, -$global_scale+1);
*/

// Output SVG
header("Content-Type: image/svg+xml");
echo '<?xml version="1.0" standalone="no"?>'."\n";
echo '<svg version="1.1"  baseProfile="full" xmlns="http://www.w3.org/2000/svg" xmlns:xlink="http://www.w3.org/1999/xlink" xmlns:ev="http://www.w3.org/2001/xml-events">'."\n";
echo '<defs>'."\n";

echo '<linearGradient id="stone_right" x1="52%" y1="0%" x2="100%" y2="100%"><stop offset="50%" stop-color="#666" /><stop offset="100%" stop-color="#333" /></linearGradient>'."\n";
echo '<linearGradient id="stone_left" x1="20%" y1="0%" x2="0%" y2="100%"><stop offset="50%" stop-color="#999" /><stop offset="100%" stop-color="#666" /></linearGradient>'."\n";
echo '<linearGradient id="stone_top" x1="0%" y1="0%" x2="0%" y2="100%"><stop offset="50%" stop-color="#CCC" /><stop offset="100%" stop-color="#AAA" /></linearGradient>'."\n";

echo '<linearGradient id="grass_right" x1="52%" y1="0%" x2="100%" y2="100%"><stop offset="30%" stop-color="#227012" /><stop offset="35%" stop-color="#5e301e" /><stop offset="50%" stop-color="#5e301e" /><stop offset="100%" stop-color="#432317" /></linearGradient>'."\n";
echo '<linearGradient id="grass_left" x1="20%" y1="0%" x2="0%" y2="100%"><stop offset="20%" stop-color="#308320" /><stop offset="25%" stop-color="#654336" /><stop offset="50%" stop-color="#654336" /><stop offset="100%" stop-color="#4e342a" /></linearGradient>'."\n";
echo '<linearGradient id="grass_top" x1="0%" y1="0%" x2="0%" y2="100%"><stop offset="50%" stop-color="#3bc021" /><stop offset="100%" stop-color="#319c1c" /></linearGradient>'."\n";

echo '<linearGradient id="dirt_right" x1="52%" y1="0%" x2="100%" y2="100%"><stop offset="50%" stop-color="#5e301e" /><stop offset="100%" stop-color="#432317" /></linearGradient>'."\n";
echo '<linearGradient id="dirt_left" x1="20%" y1="0%" x2="0%" y2="100%"><stop offset="50%" stop-color="#654336" /><stop offset="100%" stop-color="#4e342a" /></linearGradient>'."\n";
echo '<linearGradient id="dirt_top" x1="0%" y1="0%" x2="0%" y2="100%"><stop offset="50%" stop-color="#9f5f2c" /><stop offset="100%" stop-color="#845127" /></linearGradient>'."\n";

echo '<linearGradient id="wood_right" x1="52%" y1="0%" x2="100%" y2="100%"><stop offset="50%" stop-color="#554729" /><stop offset="100%" stop-color="#443922" /></linearGradient>'."\n";
echo '<linearGradient id="wood_left" x1="20%" y1="0%" x2="0%" y2="100%"><stop offset="50%" stop-color="#827251" /><stop offset="100%" stop-color="#6a5d40" /></linearGradient>'."\n";
echo '<linearGradient id="wood_top" x1="0%" y1="0%" x2="0%" y2="100%"><stop offset="50%" stop-color="#b07f16" /><stop offset="100%" stop-color="#9a721c" /></linearGradient>'."\n";

echo '<linearGradient id="water_right" x1="52%" y1="0%" x2="100%" y2="100%"><stop offset="50%" stop-color="#24389d" /><stop offset="100%" stop-color="#203188" /></linearGradient>'."\n";
echo '<linearGradient id="water_left" x1="20%" y1="0%" x2="0%" y2="100%"><stop offset="50%" stop-color="#475bc0" /><stop offset="100%" stop-color="#4455ac" /></linearGradient>'."\n";
echo '<linearGradient id="water_top" x1="0%" y1="0%" x2="0%" y2="100%"><stop offset="50%" stop-color="#4f69ed" /><stop offset="100%" stop-color="#485fd1" /></linearGradient>'."\n";

echo '</defs>'."\n";

// Translate blocks to scene
for ($i=0; $i<count($blocks); $i++) {
	$layer = $blocks[$i]; // Current layer;
	for ($j=count($layer)-1; $j>=0; $j--) {
		$y_off = floor($j/$global_row_size); // Which vertical row are we on?
		$x_off = fmod($j, $global_row_size); // What horizontal offset are we at?
		
		$draw_top = (count($blocks) > $i+1 && $blocks[$i+1][$j] > 0)? false : true; // No top if block above is solid
		$draw_left = ($j > 0 && $layer[$j-1] > 0 && fmod($j, $global_row_size) != 0)? false : true; // No left side if prior block is solid
		$draw_right = ($j >= $global_row_size && $layer[$j-$global_row_size] > 0)? false : true; // No right side if same block in prior row was solid
		
		if ($layer[$j] > 0 && ($draw_top || $draw_left || $draw_right)) {
			// Some part of the cube is visible; draw it
			list($x, $y) = dimetricToTranslate($x_off, $y_off);
			$x = $x*($global_scale-1) + $global_origin_x;
			$y = $y*($global_scale-1) + $global_origin_y - $i*($global_scale);
			switch ($layer[$j]) {
				case 1:
				case 4:
					$class = 'stone';
					break;
				case 2:
					$class = 'grass';
					break;
				case 3:
				case 60:
					$class = 'dirt';
					break;
				case 5:
				case 47:
					$class = 'wood';
					break;
				case 8:
				case 9:
					$class = 'water';
					break;
				case 10:
				case 11:
					$class = 'lava';
					break;
				case 12:
					$class = 'sand';
					break;
				case 13:
					$class = 'gravel';
					break;
				case 14:
				case 15:
				case 16:
				case 56:
				case 73:
					$class = 'ore';
					break;
				case 17:
					$class = 'log';
					break;
				case 18:
					$class = 'leaves';
					break;
				case 20:
					$class = 'glass';
					break;
				case 49:
					$class = 'obsidian';
					break;
				default:
					$class = 'stone';
			}
			if ($draw_right) {
				$right = $right_face->translate($x,$y);
				echo '<polygon points="'.$right->getPoints().'" fill="url(#'.$class.'_right)" />'."\n";
			}
			if ($draw_left) {
				$left = $left_face->translate($x,$y);
				echo '<polygon points="'.$left->getPoints().'" fill="url(#'.$class.'_left)" />'."\n";
			}
			if ($draw_top) {
				$top = $unit_square->translate($x,$y);
				echo '<polygon points="'.$top->getPoints().'" fill="url(#'.$class.'_top)" />'."\n";
			}
		}
	}
}
				
		
/*	
echo '<polygon points="'.$sample_top->getPoints().'" fill="url(#topFace)" />'."\n";
echo '<polygon points="'.$sample_left->getPoints().'" fill="url(#leftFace)" />'."\n";
echo '<polygon points="'.$sample_right->getPoints().'" fill="url(#rightFace)" />'."\n";
echo '<polygon points="'.$extra->getPoints().'" fill="url(#rightFace)" />'."\n";
*/


echo '</svg>';


///// Class Definitions /////

/**
 * Hold a graphical point
 */
class Point {
	var $x;
	var $y;
	function __construct($x, $y) {
		$this->x = floatval($x);
		$this->y = floatval($y);
	}
	
	function __toString() {
		return "(".$this->x.", ".$this->y.")";
	}
}

class Polygon {
	var $points;
	
	function __construct() {
		$args = func_get_args();
		$this->points = array(); // Empty array to start with
		foreach($args as $arg) {
			if ($arg instanceof Point) $this->points[] = $arg;
		}
	}
	
	function addPoint($point) {
		if ($point instanceof Point) {
			$this->points[] = $point;
			return true;
		} else {
			return false;
		}
	}
	
	function getPoints() {
		$str = "";
		foreach($this->points as $point) {
			$str .= $point->x.",".$point->y." ";
		}
		return substr($str,0, -1); // trim final space
	}
	
	function scale($factor) {
		$scaled = new Polygon();
		foreach($this->points as $point) {
			$scaled->addPoint(new Point($point->x*$factor, $point->y*$factor));
		}
		return $scaled;
	}
	
	function translate($x, $y) {
		$translated = new Polygon();
		foreach($this->points as $point) {
			$translated->addPoint(new Point($point->x+$x, $point->y+$y));
		}
		return $translated;
	}
}

///// Functions /////
function multiTranslate($x, $y, $polygons) {
	$final = array();
	foreach($polygons as $polygon) {
		if ($polygon instanceof Polygon) $final[] = $polygon->translate($x, $y);
	}
	return $final;
}

// Take a point on the dimetric grid, and translate it into a screen-space translation offset.
function dimetricToTranslate($x, $y) {
	$nx = 0;
	$ny = 0;
	
	// Shift by X
	$nx += cos(pi()/3)*$x;
	$ny -= sin(pi()/3)*$x;
	
	// Shift by Y
	$nx -= cos(pi()/12)*$y;
	$ny -= sin(pi()/12)*$y;
	
	return array($nx, $ny);
}