gistfile1.txt

function visibleTilesLoaded(viewer) {
    var layer = viewer.scene().layer();
    var geometry = layer.geometry();

    var visibleTilesForLevel = function(level) {
        return geometry.visibleTiles(viewer.view(), level);
    };

    var tileHasTexture = function(tile) {
        var tile = layer.textureStore().query(tile);
        return (!tile.visible || tile.hasTexture);
    };

    var reduceAnd = function(a, b) {
        return a && b;
    };

    return [].concat.apply([], geometry.levelList
            .map(visibleTilesForLevel))
        .map(tileHasTexture)
        .reduce(reduceAnd);
}