Conways Game of Life (GOL) cellular automata

ConwaysGOL.cs

using System.Collections;
using System.Collections.Generic;
using UnityEngine;

// @kurtdekker
//
// ultra dead-simple Conways Game Of Life (GOL) implementation in Unity
//
// To use:
//	Make the default blank scene with a Camera / Light
//	Pull the camera back to perhaps (0,0,-80);
//	Make a blank GameObject at (0,0,0)
//	Put this script on the blank GameObject
//	Press PLAY

public class ConwaysGOL : MonoBehaviour
{
	public int Across = 100;
	public int Down = 70;
	public float StartingDensity = 0.5f;

	bool[,] Generation;
	int[,] WorkCounts;

	GameObject[,] Presentation;

	Vector3 CalculatePosition( int i, int j)
	{
		float x = i - (Across - 1) * 0.5f;
		float y = j - (Down - 1) * 0.5f;
		return new Vector3( x, y);
	}

	void Start ()
	{
		Generation = new bool[ Across, Down];
		WorkCounts = new int[ Across, Down];
		Presentation = new GameObject[ Across, Down];

		// make presentation objects, place them appropriately
		for (int j = 0; j < Down; j++)
		{
			for (int i = 0; i < Across; i++)
			{
				var critter = GameObject.CreatePrimitive( PrimitiveType.Sphere);
				critter.transform.position = CalculatePosition(i,j);
				Presentation[i,j] = critter;
			}
		}

		// make a random starting generation
		for (int j = 0; j < Down; j++)
		{
			for (int i = 0; i < Across; i++)
			{
				Generation[i,j] = Random.value < StartingDensity;
			}
		}

		PresentGeneration();
	}

	// 0 is up, going around clockwise in 45-degree steps
	static int[] xtable8 = new int[] { 0, 1, 1, 1, 0, -1, -1, -1};
	static int[] ytable8 = new int[] { 1, 1, 0, -1, -1, -1, 0, 1};

	void CalculateOneGeneration()
	{
		// clear tallies
		for (int j = 0; j < Down; j++)
		{
			for (int i = 0; i < Across; i++)
			{
				WorkCounts[i,j] = 0;
			}
		}

		// tally to our neighbors
		for (int j = 0; j < Down; j++)
		{
			for (int i = 0; i < Across; i++)
			{
				if (Generation[i,j])
				{
					for (int dir8 = 0; dir8 < 8; dir8++)
					{
						int i2 = i + xtable8[dir8];
						int j2 = j + ytable8[dir8];

						if (i2 >= 0 && i2 < Across)
						{
							if (j2 >= 0 && j2 < Down)
							{
								WorkCounts[i2,j2]++;
							}
						}
					}
				}
			}
		}

		// create
		for (int j = 0; j < Down; j++)
		{
			for (int i = 0; i < Across; i++)
			{
				int count = WorkCounts[i,j];

				if (Generation[i,j])
				{
					bool exists = (count == 2) || (count == 3);
					Generation[i,j] = exists;
				}
				else
				{
					Generation[i,j] = count == 3;
				}
			}
		}
	}

	void PresentGeneration()
	{
		for (int j = 0; j < Down; j++)
		{
			for (int i = 0; i < Across; i++)
			{
				Presentation[i,j].SetActive( Generation[i,j]);
			}
		}
	}

	void Update()
	{
		CalculateOneGeneration();

		PresentGeneration();
	}
}