matrixcode/index.html at master · danieldreke/matrixcode · GitHub

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<!DOCTYPE html>
<html lang="en">

<head>
    <meta charset="utf-8" />
    <title>Matrix Code</title>
    <script type="text/javascript">
        var looptime = 30;
        var fontsize = 15;
        var changingsymbols = 1;
        var changingcolor = 1;
        var differentspeed = 1;
        var hue = 120; // startvalue: green
        var color = 'hsl(120, 100%, 45%)'; // default: green
        var maxwidth = window.innerWidth;
        var maxheight = window.innerHeight;
        var isrunning = false;
        var intval = null;

        window.onload = main;
        window.onresize = main;
        window.onkeydown = function (e) {
            if (e.keyCode == 32) // spacebar
                toggle_loop();
            if (e.keyCode == 'C'.charCodeAt(0))
                changingcolor = !changingcolor;
            if (e.keyCode == 'D'.charCodeAt(0))
                differentspeed = !differentspeed;
            if (e.keyCode == 'S'.charCodeAt(0))
                changingsymbols = !changingsymbols;
            if (e.keyCode == 'W'.charCodeAt(0)) {
                looptime -= 3;
                if (looptime < 3)
                    looptime = 3;
            }
            if (e.keyCode == 'Q'.charCodeAt(0))
                looptime += 3;
            if (isrunning && (e.keyCode == 'Q'.charCodeAt(0) || e.keyCode == 'W'.charCodeAt(0))) {
                clearInterval(intval);
                intval = setInterval(draw_matrix, looptime);
            }
        }

        var codes = [];
        var ypos = [];
        var charcount = 0;
        var columncount = 0;
        var frontcanvas = null;
        var backcanvas = null;
        var frontcontent = null;
        var backcontent = null;

        function resize_canvases() {
            frontcanvas.width = Math.min(window.innerWidth, maxwidth);
            frontcanvas.height = Math.min(window.innerHeight, maxheight);
            backcanvas.width = frontcanvas.width;
            backcanvas.height = frontcanvas.height;
            charcount = parseInt(frontcanvas.height / fontsize * 1.0);
            columncount = parseInt(frontcanvas.width / fontsize);
        }

        function get_randomchar() {
            // http://www.kirupa.com/forum/showthread.php?340198-The-Matrix-Movie-Fonts
            // http://de.wikipedia.org/wiki/Unicodeblock_Katakana
            return parseInt(Math.random() * 95 + 12448);
        }

        function get_randompos() {
            var charcount = parseInt(frontcanvas.height / fontsize);
            var startcell = parseInt(Math.random() * charcount * 2)
            return parseInt(-1 * startcell * fontsize);
        }

        function fill_array(arr, func) {
            for (i = 0; i < arr.length; i++)
                arr[i] = parseInt(func());
        }

        function set_symbol(symbolindex, x, y) {
            var symbol = String.fromCharCode(codes[symbolindex]);
            frontcontent.fillText(symbol, x, y - 1);
        }

        function change_symbols() {
            var randomcolumn = 0;
            var randomrow = 0;
            var randomindex = 0;
            var x = 0;
            var y = 0;
            for (k = 0; k < charcount * 1.0; k++) {
                randomcolumn = parseInt(Math.random() * columncount);
                randomrow = parseInt(Math.random() * charcount);
                x = randomcolumn * fontsize;
                y = randomrow * fontsize;
                randomindex = randomcolumn * randomrow;
                codes[randomindex] = get_randomchar();
                frontcontent.fillStyle = 'black';
                frontcontent.globalCompositeOperation = "source-over";
                frontcontent.fillRect(x, y, fontsize, fontsize);
                frontcontent.fillStyle = 'white';
                frontcontent.globalCompositeOperation = "destination-out";
                set_symbol(randomindex, x, y + fontsize);
            }
        }

        function draw_matrix() {
            // video example: https://www.youtube.com/watch?v=8ZdpA3p9ZMY
            var x = 0;
            var y = 0;
            var grad = null;
            backcontent.clearRect(0, 0, backcanvas.width, backcanvas.height);

            for (i = 0; i < columncount; i++) {
                ypos[i] += fontsize * 0.5;
                if (differentspeed)
                    if (fastcolumns[i] == 1)
                        ypos[i] += ((i + 1) % fontsize) * 1.5;

                y = ypos[i];
                if (y < 0)
                    continue;
                x = parseInt(i * fontsize);

                grad = backcontent.createLinearGradient(x, y - charcount * fontsize, x, y);
                grad.addColorStop(0.0, 'hsla(0, 0%, 0%, 0)');
                grad.addColorStop(0.4, color);
                grad.addColorStop(1 - 4 / charcount, color);
                grad.addColorStop(1 - 1 / charcount, 'white');
                backcontent.fillStyle = grad;
                backcontent.fillRect(x, parseInt(y - charcount * fontsize), fontsize, charcount * fontsize);

                if (y > frontcanvas.height + charcount * fontsize)
                    if (Math.random() > 0.5)
                    {
                        y = 0;
                        if (fastcolumns[i] == 1)
                            fastcolumns[i] = 0;
                        var isfastcolumn = Math.random() > 0.9;
                        if (isfastcolumn)
                          fastcolumns[i] = 1;
                    }
                ypos[i] = y;
            }
            if (changingsymbols)
                change_symbols();
            if (changingcolor) {
                hue += 0.3;
                hue = (hue > 360) ? 0 : hue;
                color = 'hsl(' + hue + ', 100%, 40%)';
            }
        }

        function main() {
            frontcanvas = document.getElementById('frontlayer');
            backcanvas = document.getElementById('backlayer');
            if (frontcanvas.getContext && backcanvas.getContext) {
                resize_canvases();
                if (isrunning)
                    toggle_loop();
                codes = new Array(parseInt((parseInt(4096 / fontsize) + 1) * (parseInt(2160 / fontsize) + 1)));
                fill_array(codes, get_randomchar);
                frontcontent = frontcanvas.getContext('2d');
                frontcontent.fillStyle = 'black';
                frontcontent.fillRect(0, 0, frontcanvas.width, frontcanvas.height);
                frontcontent.fillStyle = 'white';
                // https://developer.mozilla.org/samples/canvas-tutorial/6_1_canvas_composite.html
                frontcontent.globalCompositeOperation = "destination-out";
                frontcontent.font = fontsize + 'px monospace';
                for (y = 0; y < frontcanvas.height; y += fontsize)
                    for (x = 0; x < frontcanvas.width; x += fontsize) {
                        index = parseInt(x / fontsize + 1) * parseInt(y / fontsize + 1);
                        set_symbol(index, x, y);
                    }
                ypos = new Array(parseInt(4096 / fontsize) + 1);
                fastcolumns = new Array(columncount);
                fastcolumns.fill(0);
                fill_array(ypos, get_randompos);
                backcontent = backcanvas.getContext('2d');
                toggle_loop();
            }
        }

        function toggle_loop() {
            if (isrunning)
                clearInterval(intval);
            else
                intval = setInterval(draw_matrix, looptime);
            isrunning = !isrunning;
        }
    </script>
    <style type="text/css">
        body {
            overflow: hidden;
            margin: 0px;
            background-color: black;
        }
        #frontlayer,
        #backlayer {
            position: absolute;
            top: 0;
            left: 0;
        }
        #frontlayer {
            z-index: 2;
        }
        #backlayer {
            z-index: 1;
        }
    </style>
</head>

<body>
    <canvas id="frontlayer">
        Your browser does not support HTML5 canvas. Please update your browser or try another one.
    </canvas>
    <canvas id="backlayer">
        Your browser does not support HTML5 canvas. Please update your browser or try another one.
    </canvas>
</body>

</html>