debug/animate.html

<!DOCTYPE html>
<html>
<head>
    <title>Mapbox GL JS debug page</title>
    <meta charset='utf-8'>
    <meta name="viewport" content="width=device-width, initial-scale=1.0, user-scalable=no">
    <link rel='stylesheet' href='../dist/mapbox-gl.css' />
    <style>
        #map { width: 1200px; height: 800px;  }
    </style>
</head>

<body>
<div id='map'></div>

<script src='../dist/mapbox-gl-dev.js'></script>
<script src='../debug/access_token_generated.js'></script>
<script>

var map = window.map = new mapboxgl.Map({
    container: 'map',
    style: 'mapbox://styles/mapbox/streets-v11',
    center: [0, 0],
    zoom: 4
});

var radius = 30;

function line(angle, radius) {
    return {
        "type": "Feature",
        "geometry": {
            "type": "LineString",
            "coordinates": [
                [-Math.cos(angle) * radius, -Math.sin(angle) * radius + 1],
                [Math.cos(angle) * radius, Math.sin(angle) * radius + 1],
            ]
        }
    };
}

function crossWithAngle(angle) {
    return {
        "type": "FeatureCollection",
        "features": [
            line(angle - Math.PI / 4, radius),
            line(angle + Math.PI / 4, radius)
        ]
    };
}

map.on('load', function () {
    // Add a source and layer displaying a point which will be animated in a circle.
    map.addSource('lines', {
        "type": "geojson",
        "data": crossWithAngle(0)
    });

    map.addLayer({
        "id": "lines",
        "source": "lines",
        "type": "line",
        "paint": {
            "line-width": 4,
            "line-color": "#007cbf"
        }
    });

    map.addLayer({
        "id": "dot",
        "source": "lines",
        "type": "circle",
        "paint": {
            "circle-radius": 10,
            "circle-color": "#007cbf"
        }
    });

    var updates = 0;

    map.on('data', function (d) {
        if (d.sourceDataType === 'content') {
            updates++;
        }
    });

    setInterval(function () {
        console.log(updates + ' updates per second');
        updates = 0;
    }, 1000);

    function animateMarker(timestamp) {
        // Update the data to a new position based on the animation timestamp. The
        // divisor in the expression `timestamp / 1000` controls the animation speed.
        map.getSource('lines').setData(crossWithAngle(timestamp / 1000));

        // Request the next frame of the animation.
        requestAnimationFrame(animateMarker);
    }

    // Start the animation.
    animateMarker(0);
});
</script>

</body>
</html>