Create a ZIP archive with PHP in a separate directory

I have a wordpress site and I’m creating an HR plugin for the company I work for. One function allows administrators to download a zip file containing several documents. I have tested the following code which works fine but I would like the ZIP archive to be created in a directory of my choice.

function direct_download()
{
    if ($_REQUEST['action'] == 'download')
    {
        $App = new DHR_Application();
        $file_name=str_replace(" ","_",$App->Fname)."_".str_replace(" ","_",$App->Lname)."_".$App->ID;
        $txt_name=$file_name.".txt";
        $txt_path="../user-upload/temp/".$file_name.".txt";
        $arc_name=$file_name.".zip";


        $txt=$App->Fname." ".$App->Lname."rn".$App->ID;
        $file=fopen($txt_path,"w+");
        fwrite($file,$txt);

        $zip = new ZipArchive();

        if ($zip->open($arc_name, ZIPARCHIVE::CREATE )!==TRUE)
        {
            exit("cannot open <$arc_name>n");
        }
        $nameAtt1 = pathinfo($App->Att1,PATHINFO_BASENAME);
        $zip->addFile($App->Att1,$nameAtt1);
        if (($App->Att2 != '') && ($App->Att2 != null))
        {
            $nameAtt2 = pathinfo($App->Att2,PATHINFO_BASENAME);
            $zip->addFile($App->Att2,$nameAtt2);
        }

        $zip->addFile($txt_name,$txt_path);
        $zip->close();
        fclose($file);

        header("Content-type: application/zip");
        header("Content-Disposition: attachment; filename=$arc_name");
        header("Pragma: no-cache");
        header("Expire: 0");
        readfile("$arc_name");
        exit();
    }
}

Normally the ZIP archive is created in /wp-admin/ directory. I don’t want temporary files created and deleted in this directory because it runs the back end of wordpress.

When I include the path of the file in $arc_name the code breaks. I looked at the $zip->filename value and it will change the value from “C:/wamp/www/company/user-upload/temp/Tony_Beroni_000001.zip” to “C:wampwwwcompanyuser-upload\tempTony_Beroni_000001.zip”. I assume this could be an issue because of the difference between WAMP and a native Apache server(no pun intended).

Does anyone know how to create a ZIP archive with PHP in a specific directory?

Edit: I noticed that I had the parameters for $zip->addFile($txt_name,$txt_path); in reverse it should be $zip->addFile($txt_path, $txt_name);