life.js

function randInt(minv, maxv) {
    var rv = minv + Math.floor(Math.random()*(maxv-minv));
    return rv;
}

function initialize(width, height, prob) {
    var life = new Array(height);
    for (var i = 0; i<height; ++i) {
        life[i] = new Array(width);
        for (var j=0; j<width; ++j) {
            life[i][j] = false;
        }
    }

    var numFilled = (width*height*prob);
    for (var i=0;i<numFilled; ++i) {
        var ri = randInt(0, height);
        var rj = randInt(0, width);
        life[ri][rj] = true;
    }

    return life;
}

function countNeighbors(i,j,arr) {
    var h = arr.length;
    var w = arr[0].length;
    var num = 0;
    var up = i-1>0 ? i-1 : h-1;
    var down = i+1 <h-1 ? i+1 : 0;
    var left = j-1>0 ? j-1 : w-1;
    var right = j+1 < w-1 ? j+1 : 0;
    
    num += arr[up][j];
    num += arr[down][j];
    num += arr[i][left];
    num += arr[i][right];
    num += arr[up][left];
    num += arr[up][right];
    num += arr[down][left];
    num += arr[down][right];
    return num;
}

function evolve(arr) {
    var h = arr.length;
    var w = arr[0].length;

    var rval = new Array(h);
    for (var i=0;i<h;++i) {
        rval[i] = new Array(w);
    }
    for (var i=0; i<h; ++i) {
        for (var j=0; j<w; ++j) {
            var num = countNeighbors(i,j,arr);
            if (arr[i][j]) {
                if ((num < 2) || (num > 3)) {
                    rval[i][j] = false;
                } else {
                    rval[i][j] = true;
                }
            } else {
                if (num == 3) {
                    rval[i][j] = true;
                } else {
                    rval[i][j] = false;
                }
            }
        }
    }
    return rval;
}

function show(iter, arr) {
    var h = arr.length;
    var w = arr[0].length;
    for (var i=0;i<h; ++i) {
        for (var j=0;j<w; ++j) {
            if (arr[i][j]) {
                // new solidblock(new point(i,j,2*iter), new point(i+1,j+1,2*iter+1));
                new solidblock(new point(i,j,iter), new point(i+1,j+1,iter+1));
            }
        }
    }
}

function game_of_life(width, height, iterations) {
    var life_board = initialize(width, height, 0.42);

    for (var iter = 0; iter<iterations; ++iter) {
        show(iter, life_board);
        life_board = evolve(life_board);
    }
}

game_of_life(10,10,20);