var rotateY3D = function(theta) {
    var sin_t = sin(theta);
    var cos_t = cos(theta);
    
    for (var n = 0; n < nodes.length; n++) {
        var node = nodes[n];
        var x = node[0];
        var z = node[2];
        node[0] = x * cos_t - z * sin_t;
        node[2] = z * cos_t + x * sin_t;
    }
};