View source for Conway's Game of Life

[[Virtual laboratory]] > [[Conway's Game of Life]] <HR>

Here is the program, presenting [https://en.wikipedia.org/wiki/Conway%27s_Game_of_Life the game of Life] by [https://en.wikipedia.org/wiki/John_Horton_Conway John Conway]. You can draw the cells on the field with a mouse. 

{{#widget:Iframe |url=http://tm.spbstu.ru/htmlets/Tcvetkov/CelAut/CelAut_v2_release/CelAut_v2_release.html |width=630 |height=650 |border=0 }}

Download the program code: [[Media:CelAut_v2_release.zip|CelAut_v2_release.zip]]
<div class="mw-collapsible mw-collapsed" style="width:100%" >
'''The Text of the program is written in JavaScript (developed by [[Tsvetkov Denis]]):''' <div class="mw-collapsible-content"> 
File '''"CelAut_v2_release.js"'''
<syntaxhighlight lang="javascript" line start="1" enclose="div">
function MainChain(canvas) {

    // Preliminary installations
    var context = canvas.getContext("2d");                  // context for drawing
    document.oncontextmenu=function(e){return false};       // blocking of a context menu

    // *** calculation parameteres ***

    var fps = 5;             	    // frames per second

    // running of the profgam

    var w = canvas.width;		    // window width
    var h = canvas.height;		// window hight
    var n = 50;                   // quantity of cages on horizontal axis
    var m = 50;                   // quantity of cages across on vertical axis
    var cellW = w/n;              // cage width
    var cellH = h/m;              // cage hight

    var pause = true;
    var intervalID;                 // for management of operation of the automatic machine

    // Conway's life: [B = 000100000, L = 001100000]
    var B = "000100000";            // birth code
    var L = "001100000";            // survival code

    // Mouse parameters

    var mouseX;     var mouseY;                 // cursor coordinates of a mouse

    canvas.onmousedown = function(e){           // function when pressing a key of a mouse
        var life;
        if (e.which == 1) life = true;          // the cage is born by pressing the left key of a mouse 
        else if (e.which == 3) life = false;    // the cage is dead by pressing the left key of a mouse 
        else return;

        setCell(e, life);
        canvas.onmousemove = function(e) {setCell(e, life);};   // shift cursor
    };

    document.onmouseup = function(e){  
        canvas.onmousemove = null;       
    };

    function refreshMouseCoords(e){             // procedure updates coordinates in the mouseX and mouseY variables
        var rect = canvas.getBoundingClientRect();
        mouseX = e.clientX - rect.left;
        mouseY = e.clientY - rect.top;
    }

    // working with massive

    var cells;                      // massive of cages
    var cellsBuf = [];              // the buffer for calculation of the following step
    for (var i = 0; i < n; i++) cellsBuf[i] = [];
    function generateRandomField(n, m) {        // each cage is filled with casual value is live/is dead
        cells = [];
        for (var i = 0; i < n; i++) {
            cells[i] = [];
            for (var j = 0; j < m; j++) {
                cells[i][j] = (Math.random() >= 0.5);
            }
        }
    }

    function setCell(e, life){                  // to give to a cage a certain state from pressing of a key of a mouse
        refreshMouseCoords(e);                  // update coordinates in the mouseX and mouseY variables
        if (mouseX < 0 || mouseX >= w || mouseY < 0 || mouseY >= h) return;         // check for wrong coordinates
        var i = Math.floor(mouseX/cellW);       // cage on horizontal axis
        var j = Math.floor(mouseY/cellH);       // cage on vertical axis
        if (cells[i][j] != life) {
            cells[i][j] = life;
            draw();
        }
    }

    MainChain.prototype.clear = function(){
        for (var i = 0; i < n; i++)
            for (var j = 0; j < m; j++)
                cells[i][j] = false;
        draw();
        stopSystem();
    };

    // for management of operation of the automatic machine

    function step() {
        tick();
        draw();
    }

    MainChain.prototype.changePauseState = function() {          // pause
        if (!pause) stopSystem();
        else startSystem()
    };

    MainChain.prototype.nextStep = function(){                   // next step
        stopSystem();
        step();
    };

    function startSystem() {
        pause = false;
        intervalID = setInterval(step, 1000/fps);
        document.getElementById('pause').value = "Stop";
    }

    function stopSystem() {
        pause = true;
        clearInterval(intervalID);
        document.getElementById('pause').value = "Next step";
    }

    // calculation part of the programm

    // the functions providing frequency of system
    function next(i, n) {if (i == (n-1)) return 0; else return i+1;}
    function prev(i, n) {if (i == 0) return n-1; else return i-1;}

    function tick(){                           
        // copyingа cells to cellsBuf
        for (var i0 = 0; i0 < n; i0++)
            for (var j0 = 0; j0 < m; j0++)
                cellsBuf[i0][j0] = cells[i0][j0];

        for (var i = 0; i < n; i++) {
            for (var j = 0; j < m; j++) {

                // calculation of amount of living cells around the considered cage
                var near = 0;
                if (cellsBuf[prev(i, n)] [prev(j, m)])   near++;
                if (cellsBuf[prev(i, n)] [j])            near++;
                if (cellsBuf[prev(i, n)] [next(j, m)])   near++;
                if (cellsBuf[i]          [prev(j, m)])   near++;
                if (cellsBuf[i]          [next(j, m)])   near++;
                if (cellsBuf[next(i, n)] [prev(j, m)])   near++;
                if (cellsBuf[next(i, n)] [j])            near++;
                if (cellsBuf[next(i, n)] [next(j, m)])   near++;

                if (cellsBuf[i][j])                     // cell is alive
                    cells[i][j] = (L[near] == '1');     // check of a condition of a survival on a binomial of L
                else                                    // cell is dead
                    cells[i][j] = (B[near] == '1');     // check of a condition of the birth on B binomial

            }
        }
    }

    // drawing

    function draw(){
        context.clearRect(0, 0, w, h);          // clear the screen
        for (var i = 0; i < n; i++){
            for (var j = 0; j < m; j++){
                if (cells[i][j]){
                    context.beginPath();
                    context.rect(i*cellW, j*cellH, cellW, cellH);
                    context.closePath();
                    context.fill();
                }
            }
        }
    }

    // Run system
    generateRandomField(n, m);                  // generate field
    startSystem();

}
</syntaxhighlight>
Файл '''"CelAut_v2_release.html"'''
<syntaxhighlight lang="html5" line start="1" enclose="div">
<!DOCTYPE html>
<html>
<head>
    <title>Cellular automaton</title>
    <script src="CelAut_v2_release.js"></script>
</head>
<body>
    <canvas id="canvasCelAut" width="600" height="600" style="border:1px solid #000000;"></canvas><br>
    <input id="pause" type="button" name="" style="width: 100px" onclick="app.changePauseState();return false;"/>
    <input type="button" name="" onclick="app.nextStep();return false;" value="Next step"/>
    <input type="button" name="" onclick="app.clear();return false;" value="Clear the field"/>
    <script type="text/javascript">var app = new MainChain(document.getElementById('canvasCelAut'));</script>
</body>
</html>
</syntaxhighlight>
</div>
</div>

[[:ru:JavaScript - Клеточный автомат|Here]] you can find the previous versions of the program.

<!--[[Category: Virtual Laboratory]]
[[Category: Programming]]
-->