Javascript
I think this mostly works. There's some wonky behavior where I spawn all the new bears/lumberjacks in sync and right next to each other because laziness in insertions.
This implementation does not allow lumberjacks to stand on saplings, cause you know, trampling saplings is bad. Fiddle art uses colored rectangles by default, change the second line to false to use letters to draw.
HTML:
<canvas id="c" width="1" height="1"></canvas><div id="p1"></div><div id="p2"></div><div id="p3"></div><div id="p4"></div>Js:
var n = 10; // Size of the gridvar drawUsingColor = true; // If true, draws colors for each entity instead :Dvar intervalTime = 1000; // how often each tick happens, in millisecondsvar jackRatio = 0.1;var treeRatio = 0.5;var bearRatio = 0.02;var size = 48; // Pixels allocated (in size x size) for each entityvar font = "30px Lucida Console"; // if drawUsingColor is falsevar bearColor = '#8B4513'; // Saddlebrownvar elderColor = '#556B2F'; // DarkOliveGreenvar lumberjackColor = '#B22222'; // Firebrickvar treeColor = '#008000'; // Greenvar saplingColor = '#ADFF2F'; // GreenYellow// Game rules:var spawnSaplingChance = 0.1;var elderTreeAge = 120;var elderSaplingChance = 0.2;var treeAge = 12;var lumberjackRange = 3;var bearRange = 5;var zooPeriod = 12; // If a maul happens within this periodvar lumberPeriod = 12; // New lumberjacks hired in this periodvar time = 1;var world;var n2 = n * n; //because one saved keystrokevar zooqueue = [];var lumberqueue = [];var canvas = document.getElementById('c'); // Needs more jqueryvar context = canvas.getContext('2d');context.font = font;// various statisticsvar treesAlive = 0;var jacksAlive = 0;var bearsAlive = 0;var currentLumber = 0;var lumberjacksMauled = 0;var recentEvents = '';// Entity is a bear, eldertree, lumberjack, tree, sapling, with age. aka belts.function Entity(belts, birthday) { this.type = belts; this.age = 0; this.birthday = birthday;}function initWorld() { canvas.height = size * n; canvas.width = size * n; world = new Array(n2); // One pass spawning algorithm: numEntity = number of entity left to spawn // If rand() in range [0,numtrees), spawn tree // if rand() in range [numtrees, numtrees+numjacks), spawn lumberjack // if rand() in range [numtrees+numjacks, numtrees+numjacks+numbears), spawn bear var numTrees = treeRatio * n2; var numJacks = jackRatio * n2; var numBears = bearRatio * n2; var godseed = new Array(n2); for (var i = 0; i < n2; i++) { godseed[i] = i; } shuffle(godseed); for (var i = 0; i < n2; i++) { var god = godseed.pop(); if (god < numTrees) { world[i] = new Entity('T', 0); treesAlive++; } else if (god < numTrees + numJacks) { world[i] = new Entity('L', 0); jacksAlive++; } else if (god < numTrees + numJacks + numBears) { world[i] = new Entity('B', 0); bearsAlive++; } // console.log(world, i); } // populate zoo array, lumber array for (var i = 0; i < zooPeriod; i++) { zooqueue.push(0); } for (var i = 0; i < lumberPeriod; i++) { lumberqueue.push(0); }}animateWorld = function () { recentEvents = ''; computeWorld(); drawWorld(); time++; $('#p1').text(treesAlive +' trees alive'); $('#p2').text(bearsAlive +' bears alive'); $('#p3').text(jacksAlive +' lumberjacks alive'); $('#p4').text(recentEvents);};function computeWorld() { zooqueue.push(lumberjacksMauled); lumberqueue.push(currentLumber); // Calculate entity positions for (var i = 0; i < n2; i++) { if (world[i]) { switch (world[i].type) { case 'B': bearStuff(i); break; case 'E': elderStuff(i); break; case 'L': lumberjackStuff(i); break; case 'T': treeStuff(i); break; case 'S': saplingStuff(i); break; } } } // Pop the # mauls from zooPeriod's ago, if lumberjacksMauled > oldmauls, then someone was eaten. var oldmauls = zooqueue.shift(); if (time % zooPeriod === 0) { if (lumberjacksMauled > oldmauls) { if (remove('B') == 1) { bearsAlive--; recentEvents += 'Bear sent to zoo! '; } } else { bearsAlive++; spawn('B'); recentEvents += 'New bear appeared! '; } } var oldLumber = lumberqueue.shift(); if (time % lumberPeriod === 0) { // # lumberjack to hire var hire = Math.floor((currentLumber - oldLumber) / jacksAlive); if (hire > 0) { recentEvents += 'Lumber jack hired! ('+ hire +') '; while (hire > 0) { jacksAlive++; spawn('L'); hire--; } } else { if (remove('L') == 1) { recentEvents += 'Lumber jack fired! '; jacksAlive--; } else { } } } // Ensure > 1 lumberjack if (jacksAlive === 0) { jacksAlive++; spawn('L'); recentEvent += 'Lumberjack spontaneously appeared'; }}// Not the job of spawn/remove to keep track of whatever was spawned/removedfunction spawn(type) { var index = findEmpty(type); if (index != -1) { world[index] = new Entity(type, time); } // recentEvents += 'Spawned a '+ type +'\n';}function remove(type) { var index = findByType(type); if (index != -1) { world[index] = null; return 1; } return -1; // recentEvents += 'Removed a '+ type +'\n';}// Searches in world for an entity with type=type. Currently implemented as// linear scan, which isn't very randomfunction findByType(type) { for (var i = 0; i < n2; i++) { if (world[i] && world[i].type == type) return i; } return -1;}// Also linear scan function findEmpty(type) { for (var i = 0; i < n2; i++) { if (!world[i]) { return i; } } return -1;}function bearStuff(index) { if (world[index].birthday == time) { return; } // Wander around var tindex = index; for (var i = 0; i < lumberjackRange; i++) { var neighbors = get8Neighbor(tindex); var mov = neighbors[Math.floor(Math.random() * neighbors.length)]; if (world[mov] && world[mov].type == 'L') { recentEvents += 'Bear ('+ index % 10 +','+ Math.floor(index / 10) +') mauled a Lumberjack ('+ mov % 10 +','+ Math.floor(mov / 10) +') !'; lumberjacksMauled++; jacksAlive--; world[mov] = new Entity('B', time); world[mov].age = ++world[index].age; world[index] = null; return; } tindex = mov; } if (!world[tindex]) { world[tindex] = new Entity('B', time); world[tindex].age = ++world[index].age; world[index] = null; }}function elderStuff(index) { if (world[index].birthday == time) { return; } neighbors = get8Neighbor(index); // spawn saplings for (var i = 0; i < neighbors.length; i++) { if (!world[neighbors[i]]) { if (Math.random() < elderSaplingChance) { world[neighbors[i]] = new Entity('S', time); treesAlive++; } } } // become older world[index].age++;}function lumberjackStuff(index) { if (world[index].birthday == time) { return; } // Wander around var tindex = index; for (var i = 0; i < lumberjackRange; i++) { var neighbors = get8Neighbor(tindex); var mov = neighbors[Math.floor(Math.random() * neighbors.length)]; if (world[mov] && (world[mov].type == 'T' || world[mov].type == 'E')) { world[mov].type == 'T' ? currentLumber++ : currentLumber += 2; treesAlive--; world[mov] = new Entity('L', time); world[mov].age = ++world[index].age; world[index] = null; return; } tindex = mov; } if (!world[tindex]) { world[tindex] = new Entity('L', time); world[tindex].age = ++world[index].age; world[index] = null; }}function treeStuff(index) { if (world[index].birthday == time) { return; } neighbors = get8Neighbor(index); // spawn saplings for (var i = 0; i < neighbors.length; i++) { if (!world[neighbors[i]]) { if (Math.random() < spawnSaplingChance) { world[neighbors[i]] = new Entity('S', time); treesAlive++; } } } // promote to elder tree? if (world[index].age >= elderTreeAge) { world[index] = new Entity('E', time); return; } // become older world[index].age++;}function saplingStuff(index) { if (world[index].birthday == time) { return; } // promote to tree? if (world[index].age > treeAge) { world[index] = new Entity('T', time); return; } world[index].age++;}// Returns array containing up to 8 valid neighbors.// Prolly gonna break for n < 3 but oh wellfunction get8Neighbor(index) { neighbors = []; if (index % n != 0) { neighbors.push(index - n - 1); neighbors.push(index - 1); neighbors.push(index + n - 1); } if (index % n != n - 1) { neighbors.push(index - n + 1); neighbors.push(index + 1); neighbors.push(index + n + 1); } neighbors.push(index - n); neighbors.push(index + n); return neighbors.filter(function (val, ind, arr) { return (0 <= val && val < n2) });}// Each entity allocated 5x5px for their artfunction drawWorld() { context.clearRect(0, 0, canvas.width, canvas.height); for (var i = 0; i < n2; i++) { if (world[i]) { var x = i % n; var y = Math.floor(i / n); switch (world[i].type) { case 'B': drawBear(x, y); break; case 'E': drawElder(x, y); break; case 'L': drawJack(x, y); break; case 'T': drawTree(x, y); break; case 'S': drawSapling(x, y); break; } } }}function drawBear(x, y) { if (drawUsingColor) { drawRect(x * size, y * size, size, size, bearColor); } else { drawLetter(x * size, y * size, 'B'); }}function drawElder(x, y) { if (drawUsingColor) { drawRect(x * size, y * size, size, size, elderColor); } else { drawLetter(x * size, y * size, 'E'); }}function drawJack(x, y) { if (drawUsingColor) { drawRect(x * size, y * size, size, size, lumberjackColor); } else { drawLetter(x * size, y * size, 'J'); }}function drawTree(x, y) { if (drawUsingColor) { drawRect(x * size, y * size, size, size, treeColor); } else { drawLetter(x * size, y * size, 'T'); }}function drawSapling(x, y) { if (drawUsingColor) { drawRect(x * size, y * size, size, size, saplingColor); } else { drawLetter(x * size, y * size, 'S'); }}function drawLine(x1, y1, x2, y2, c) { context.beginPath(); context.moveTo(x1, y1); context.lineTo(x2, y2); context.lineWidth = 3; context.strokeStyle = c; context.stroke();}function drawRect(x, y, w, h, c) { context.fillStyle = c; context.fillRect(x, y, w, h);}function drawLetter(x, y, l) { context.fillText(l, x, y);}$(document).ready(function () { initWorld(); intervalID = window.setInterval(animateWorld, intervalTime); /*$('#s').click(function() { animateWorld(); })*/});// http://stackoverflow.com/questions/2450954/how-to-randomize-shuffle-a-javascript-arrayfunction shuffle(array) { var currentIndex = array.length, temporaryValue, randomIndex; // While there remain elements to shuffle... while (0 !== currentIndex) { // Pick a remaining element... randomIndex = Math.floor(Math.random() * currentIndex); currentIndex -= 1; // And swap it with the current element. temporaryValue = array[currentIndex]; array[currentIndex] = array[randomIndex]; array[randomIndex] = temporaryValue; } return array;}