Procedural Generation

This week I’ve done some procedural generation using cellular automata. This was for generating coral reef inside levels. The coral reef acts as another obstacle that the player must avoid touching. Here is a look at some of the outputs of the generation:

Both the foreground and background coral are procedurally generated

The background coral uses a different tile set and tile size

The generation can create interesting loops such at this some times

To begin I had to write a grid structure as I found out LibGDX didn’t have one included. After a little research on different ways to implement a grid, I choose to represent mine as an Array of Arrays, which although might not be that efficient, is pretty easy to implement and understand, so heres the grid class I came up with:

package com.me.mygdxgame;

import com.badlogic.gdx.utils.Array;

public class Grid {

private Array<Array<Boolean>> grid = new Array<Array<Boolean>>();
private int rows;
private int collums;

public Grid(int rows, int collums)
{
this.rows = rows;
this.collums = collums;

//populate the grid with false values
for (int i= 0; i < rows; i ++)
{
Array<Boolean> tempArray = new Array<Boolean>();
for (int j = 0; j < collums; j++)
{
tempArray.add(false);
}
grid.add(tempArray);
}
}

/**
* Used to get the value of a cell from the grid
* @param row the row of the cell
* @param collum the columns of the cell
* @return the value of the cell
*/
public boolean getTile(int row, int collum)
{
return grid.get(row).get(collum);
}

/**
* Used to set the value of a cell in the grid
* @param row the row of the cell
* @param collum the columns of the cell
* @param aBool the value of the cell
*/
public void setTile(int row, int collum, boolean aBool)
{
grid.get(row).set(collum, aBool);
}

/**
*
* @return the number of horizontal rows in the grid
*/
public int Rows()
{
return rows;
}

/**
*
* @return the number of vertical columns in the grid
*/
public int Columns()
{
return collums;
}

public void printGrid()
{
for (int i= 0; i < rows; i ++)
{
String aString = new String();
for (int j = 0; j < collums; j++)
{
if (getTile(i,j) == true)
{
aString = aString + "1";
}
else
{
aString = aString + "0";
}
}
System.out.println(aString);
}
}
}

Once I had the grid, I ported the code from a flash demo I made that created cave/caverns using cellular automata. From there I just spent some time playing around with the rules. The main rules are cells with less than 3 neighbour cells that are ‘alive’ will die that pass, and cells surrounded by 5 or more living cells become ‘alive’ if they aren’t already alive. I do 5 iterations of these rules before doing a few special rule sets at the end to help clean up situations such as 1*1 single living cells and to shape the coral a little better.

Once created each cell auto tiles by working out how many cells it is surrounded by and in what positions to determine which tile to use for itself. I use two layers of coral, one for the foreground that when touched ‘hurts’ the player, and the other is a background layer just for aesthetics. The background layer uses bigger size cells, so has less cells in its grid. As such I fill the gird with more noise to start, but besides that it generates using the same rules as the foreground cells, and just auto tiles using a different tile set.

I am pretty pleased with the results of the generation, and have additional rules in place to make levels generate with more coral in later levels to make them harder as you progress, which I feel works pretty well.

This week I am planning to think about the design of the game more, as I feel it is more tedious to play than it is fun to play, so I will try and think of ways to make the game more fun!