index.php

<?php 

set_time_limit(300); // 5 Minutes adjust as needed
ini_set('memory_limit', '3G'); // 3 GB Adjust as needed


// https://github.com/geekgirljoy/PHP/blob/master/Loose%20Code/SigmoidFunction.php
function sigmoid($t){
    return 1 / (1 + exp(-$t));
}


// Roughness Level
$min_roughness = -4;
$max_roughness = 4;

// Water Level
if(isset($_POST["water-level"])){$water_level = $_POST["water-level"];}
else{$water_level = -0.3;}

if(isset($_POST["snow-level"])){$snow_level = $_POST["snow-level"];}
else{$snow_level = 2;}


// Display Type
if(isset($_POST["display-type"])){$display_type = $_POST["display-type"];}
else{$display_type = 'map';}


// Terrain Type
if(isset($_POST["terrain-type"])){$terrain_type = $_POST["terrain-type"];}
else{$terrain_type = 'lush';}


// Apply Color Variance
if(isset($_POST["apply-variance"])){$apply_variance = $_POST["apply-variance"];}
else{$apply_variance = false;}

// Red Variance
if(isset($_POST["red-variance"])){$red_variance = $_POST["red-variance"];}
else{$red_variance = 0;}

// Green Variance
if(isset($_POST["green-variance"])){$green_variance = $_POST["green-variance"];}
else{$green_variance = 0;}

// Blue Variance
if(isset($_POST["blue-variance"])){$blue_variance = $_POST["blue-variance"];}
else{$blue_variance = 0;}



// Step 1. Determine the grid $exponent size
if(isset($_POST["exponent"])){$exponent = $_POST["exponent"];}
else{$exponent = 6;}



// Step 2. Raise 2 to the power of $exponent
// because we start counting with 0 we don't add 1
// this is the length of the rows and columns
$size =  pow(2, $exponent);

// Step 3. Create a $terrain array of (row $size, col $size) 
// and populate with nulls so we can check if the position 
// value has been set yet
$terrain = array_fill(0, $size+1, array_fill(0, $size+1, NULL));

// Step 4. Set the four corner points of $terrain
// to initial random values within the acceptable roughness range.
$a = $terrain[0][0] = mt_rand($min_roughness, $max_roughness);
$b = $terrain[0][$size] = mt_rand($min_roughness, $max_roughness);
$c = $terrain[$size][0] = mt_rand($min_roughness, $max_roughness);
$d = $terrain[$size][$size] = mt_rand($min_roughness, $max_roughness);
$average = $a + $b + $c + $d;

// Step 5. Set Center (Diamond Step)
$row = $size/2;
$col = $size/2;
$e = $terrain[$row][$col] = ( $average + mt_rand($min_roughness, $max_roughness)) / 5;



// Step 6. Alternate between the diamond and square walks until all array values have been set.
$chunk_size = $size;
for($level = 1; ($chunk_size / $level) > 0.1; $level++){
	for($row_offset = 0; $row_offset <= $size; $row_offset+=$chunk_size){
		for($col_offset = 0; $col_offset <= $size; $col_offset+=$chunk_size){
			
			// Do (Square Step)
			// if the position is not already set then set it
			if(!isset($terrain[$row_offset - $chunk_size/2][$col_offset])){
				$terrain[$row_offset - $chunk_size/2][$col_offset] = ($average + mt_rand($min_roughness, $max_roughness)) / 5;
			}
			$a = $terrain[$row_offset - $chunk_size/2][$col_offset];
			
            // if the position is not already set then set it
			if(!isset($terrain[$row_offset][$col_offset - $chunk_size/2])){
				$terrain[$row_offset][$col_offset - $chunk_size/2] = ($average + mt_rand($min_roughness, $max_roughness)) / 5;
			}
			$b = $terrain[$row_offset][$col_offset - $chunk_size/2];
			
			// if the position is not already set then set it
			if(!isset($terrain[$row_offset][$col_offset + $chunk_size/2])){
				$terrain[$row_offset][$col_offset + $chunk_size/2] = ($average + mt_rand($min_roughness, $max_roughness)) / 5;
			}
			$c = $terrain[$row_offset][$col_offset + $chunk_size/2];
			
			// if the position is not already set then set it
			if(!isset($terrain[$row_offset + $chunk_size/2][$col_offset])){
				$terrain[$row_offset + $chunk_size/2][$col_offset] = ($average + mt_rand($min_roughness, $max_roughness)) / 5;
			}
			$d = $terrain[$row_offset + $chunk_size/2][$col_offset];
			
			// Computer the average height of $a + $b + $c + $d
			$average = $a + $b + $c + $d;
						
			// Set Center (Diamond Step)
			// if the position is not already set then set it
			if(!isset($terrain[$row_offset + $chunk_size/2][$col_offset + $chunk_size/2])){
				$terrain[$row_offset + $chunk_size/2][$col_offset + $chunk_size/2] = ($average + mt_rand($min_roughness, $max_roughness)) / 5;
			}
			$e = $terrain[$row_offset + $chunk_size/2][$col_offset + $chunk_size/2];
		}
	}

	// Reduce the chunk size
	$chunk_size = $chunk_size/2;
}



$rows = $size;
$cols = $size;
$image = imagecreatetruecolor($rows, $cols); // Create the image resource


// Color Terrain
for ($row = 0; $row < $rows; $row++) {
	for ($col = 0; $col < $cols; $col++) {
		
	  $value =  sigmoid($terrain[$row][$col])*255;
	  
	  // ground
	  if($terrain[$row][$col] > $water_level && $terrain[$row][$col] < $snow_level){
		  if($terrain_type == 'moon'){$color = imagecolorallocate($image, $value, $value , $value);}
		  elseif($terrain_type == 'lush'){$color = imagecolorallocate($image, 0, $value , 0);}
		  elseif($terrain_type == 'desert'){$color = imagecolorallocate($image, $value, $value/2 , $value/4);}
		  elseif($terrain_type == 'alien'){$color = imagecolorallocate($image, $value, $value/2 , $value/1);}
      }
	  // snow
	  elseif($terrain[$row][$col] >= $snow_level){
		  $color = imagecolorallocate($image, 255-$value/3, 255-$value/3,255-$value/3);
      }
	  // water
	  else{
		  if($terrain_type != 'moon'){ $color = imagecolorallocate($image, 0 , 0, $value); }
		  else{$color = imagecolorallocate($image, $value, $value , $value);}
	  }
      imagesetpixel($image, $row, $col, $color); // Plot the current terrain position
	  
	  // this adds more color variance
	  // which gives us prettier pictures with seemingly
	  // more detail than there really is
	  if($apply_variance == true){
		  $color = imagecolorsforindex($image, imagecolorat($image, $row, $col));
		  $color['red']  *= $red_variance;
		  $color['green']  *= $green_variance;
		  $color['blue'] *= $blue_variance;
		  $color = imagecolorallocate($image, $color['red'], $color['green'], $color['blue']);
          imagesetpixel($image, $row, $col, $color);  
	  }
	  
	}
}

imagejpeg($image , "terrain.jpg"); // Save the image 
imagedestroy($image); // Free memory
?>
<html>
<head>
<title>Ancestor Simulations Generating Planet Terrain</title>
<link rel="stylesheet" type="text/css" href="style.css">
</head>
<body>

<div id="menu-container" width="300px" height="500px">
  <ul id="menu-toggle" width="300px" height="500px">
	<form id="terrain-generator" action="#" method="POST">
	
	    <label for="exponent">Map Size <span id="exponent-number"><?php echo $exponent . ' (' . $size . 'x' . $size .'px)'; ?></span></label>	
		<input type="range" id="exponent" name="exponent" min="2" max="12" value="<?php echo $exponent; ?>" onchange="SettingsSliderChange(this.id)"><br>
		
		<label for="display-type">Display Type</label><br>
		<select id="display-type" name="display-type">
			<option value="map" <?php if($display_type == 'map'){echo 'selected';}?>>Terrain Map</option>
			<option value="planet" <?php if($display_type == 'planet'){echo 'selected';}?>>Planet</option>
		</select>
		
		<label for="terrain-type">Terrain Color Palette</label><br>
		<select id="terrain-type" name="terrain-type">
			<option value="moon" <?php if($terrain_type == 'moon'){echo 'selected';}?>>Moon</option>
			<option value="lush" <?php if($terrain_type == 'lush'){echo 'selected';}?>>Lush</option>
			<option value="desert" <?php if($terrain_type == 'desert'){echo 'selected';}?>>Desert</option>
			<option value="alien" <?php if($terrain_type == 'alien'){echo 'selected';}?>>Alien</option>
		</select>
		
		<label for="apply-variance">Apply Color Variance</label><br>
		<select id="apply-variance" name="apply-variance" onchange="ToggleDisplayVariance()">
			<option value="0" <?php if($apply_variance == false){echo 'selected';}?>>No</option>
			<option value="1" <?php if($apply_variance == true){echo 'selected';}?>>Yes</option>
		</select>
		
		<div id="variances" <?php if($apply_variance == false){echo 'style="display:none;"'; }?>>
		<label for="red">Red <span id="red-number"><?php echo $red_variance; ?></span></label>	
		<input type="range" id="red" name="red-variance" min="-1" max="255" value="<?php echo $red_variance; ?>" onchange="SettingsSliderChange(this.id)"><br>
		
		<label for="green">Green <span id="green-number"><?php echo $green_variance; ?></span></label>	
		<input type="range" id="green" name="green-variance" min="-1" max="255" value="<?php echo $green_variance; ?>" onchange="SettingsSliderChange(this.id)"><br>
		
		<label for="blue">Blue <span id="blue-number"><?php echo $blue_variance; ?></span></label>	
		<input type="range" id="blue" name="blue-variance" min="-1" max="255" value="<?php echo $blue_variance; ?>" onchange="SettingsSliderChange(this.id)"><br>
		</div>
		
		
		<label for="water-level">Water</label><br>
		<select id="water-level" name="water-level" >
			<option value="-4" <?php if($water_level == -4){echo 'selected';}?>>None</option>
			<option value="-1" <?php if($water_level == -1){echo 'selected';}?>>Puddles</option>
			<option value="-0.7" <?php if($water_level == -0.7){echo 'selected';}?>>Small Lakes</option>
			<option value="-0.3" <?php if($water_level == -0.3){echo 'selected';}?>>Lakes</option>
			<option value="-0.1" <?php if($water_level == -0.1){echo 'selected';}?>>Large Lakes</option>
			<option value="0.5" <?php if($water_level == 0.5){echo 'selected';}?>>Big Islands</option>
			<option value="1" <?php if($water_level == 1){echo 'selected';}?>>Small Islands</option>
			<option value="2.5" <?php if($water_level == 2.5){echo 'selected';}?>>Fewer Small Islands</option>
			<option value="4" <?php if($water_level == 4){echo 'selected';}?>>Water World</option>
		</select>
		
		<label for="snow-level">Snow</label><br>
		<select id="snow-level" name="snow-level" >
			<option value="2" <?php if($snow_level == 2){echo 'selected';}?>>None</option>
			<option value="1" <?php if($snow_level == 1){echo 'selected';}?>>Little Snow Capped Peaks</option>
			<option value="0.7" <?php if($snow_level == 0.7){echo 'selected';}?>>Small Snow Capped Peaks</option>
			<option value="0.5" <?php if($snow_level == 0.5){echo 'selected';}?>>Large Snow Capped Peaks</option>
			<option value="0.3" <?php if($snow_level == 0.3){echo 'selected';}?>>Winter Wonderland!</option>
			<option value="-0.5" <?php if($snow_level == -0.5){echo 'selected';}?>>Ice World</option>
		</select>

		<input type="submit" value="Generate">
	</form>
	<button onclick="RandomizeSettings()">Generate Random</button>
	<a href="terrain.jpg" download>
	<button>Save</button>
	</a>
	<script>
	// Slider changed update value
	function SettingsSliderChange(element) {
		var val = document.getElementById(element).value;
		if(element == 'exponent'){
			var px = Math.pow(2, val) + 1;
			var size = " (" + px + "x" + px + "px" + ")";
			document.getElementById(element + "-number").innerHTML = val + size;
		}
		else{
		    document.getElementById(element + "-number").innerHTML = val;
		}
	}
	
	// Show / Hide variances div
	function ToggleDisplayVariance(){
		if(document.getElementById('apply-variance').selectedIndex == 1){
	        document.getElementById('variances').style.display = 'block';
		}
		else{
			document.getElementById('variances').style.display = 'none';
		}
	}
	
	// Generate Random clicked
	function RandomizeSettings(){
		
		// terrain-type
		// 0 Moon
		// 1 Lush
		// 2 Desert
		// 3 Alien
		document.getElementById('terrain-type').selectedIndex = Math.random() * (3 - 0) + 0;

		
	   	// apply-variance
		// 0 No
		// 1 Yes
	    document.getElementById('apply-variance').selectedIndex = 1; // Apply variance
		ToggleDisplayVariance(); // Show Variances Div
		
		
		// new values for red, blue, green
		var red = document.getElementById('red').value = Math.round(Math.random() * (255 - 0) + 0);
		var blue = document.getElementById('blue').value = Math.round(Math.random() * (255 - 0) + 0);
		var green = document.getElementById('green').value = Math.round(Math.random() * (255 - 0) + 0);
		document.getElementById('red-number').innerHTML = red;
		document.getElementById('green-number').innerHTML = green;
		document.getElementById('blue-number').innerHTML = blue;
		
		
		// water-level
		// None
		// Puddles
		// Small Lakes
		// Lakes
		// Large Lakes
		// Big Islands
		// Small Islands
		// Fewer Small Islands
		// Water World		
		var water_levels = [-4, -1, -0.7, -0.3, -0.1, 0.5, 1, 2.5, 4];
		document.getElementById('water-level').selectedIndex = water_levels[Math.round(Math.random() * ((water_levels.length - 1) - 0) + 0)];
		
		// snow-level
		// None
		// Little Snow Capped Peaks
		// Small Snow Capped Peaks
		// Large Snow Capped Peaks
		// Winter Wonderland!
		// Ice Planet
		var snow_levels = [2, 1, 0.7, 0.5, 0.3, -0.5];
		document.getElementById('snow-level').selectedIndex = snow_levels[Math.round(Math.random() * ((snow_levels.length - 1) - 0) + 0)];
        // submit form		
		document.forms["terrain-generator"].submit();
	}

	  	
	</script>
  </ul>
</div>



<img id="terrain" src="terrain.jpg" <?php if($display_type == 'planet'){echo 'class="planet-view"';}?>>


</body>
</html>