SteamVR Headless Mode Toggle Python Script

toggle_headless.py

#!python
# coding: utf-8

# This is a simple script to quickly switch between HMD mode and headless mode with Vive in SteamVR
# It uses symlinks to ensure that SteamVR will continue to run and always preserves the original files, 
# This should be able to be rerun following updates (assuming the configs haven't structurally changes 
# along with anything else) -- symlinks require running with elevated priviledges 

import sys, os, ctypes, time, json, shutil
from winreg import QueryValueEx, HKEY_CURRENT_USER, OpenKey

kdll = ctypes.windll.LoadLibrary("kernel32.dll")
steamVR_launch = r"steam://rungameid/250820"
steamVRRegEntry = r"SOFTWARE\Valve\Steam\Apps\250820"
steam_root = U"C:\\Program Files (x86)\\Steam"
steamvr_null_driver_settings = U"\\steamapps\\common\\SteamVR\\drivers\\null\\resources\\settings\\default.vrsettings"
steamvr_resource_settings = U"\\steamapps\\common\\SteamVR\\resources\\settings\\default.vrsettings"


def runAsAdmin(argv=None, debug=False):
    shell32 = ctypes.windll.shell32
    if argv is None and shell32.IsUserAnAdmin():
        return True

    if argv is None:
        argv = sys.argv
    if hasattr(sys, '_MEIPASS'):
        # Support pyinstaller wrapped program.
        arguments = map(str, argv[1:])
    else:
        arguments = map(str, argv)
    argument_line = u' '.join(arguments)
    executable = str(sys.executable)
    if debug:
        print ('Command line: ', executable, argument_line)
    ret = shell32.ShellExecuteW(None, u"runas", executable, argument_line, None, 1)
    if int(ret) <= 32:
        return False
    return None

if __name__ == '__main__':

    ret = runAsAdmin()
    if ret is True:
        # we have elevated permissions

        # verify steam is installed installation
        if not os.path.exists(steam_root):
            print(f'\n   Steam does not seem to be installed ({steam_root})\n')
            time.sleep(2)
            exit

        # check if steamvr is running, if so, wait for them to close steamvr
        isRunning = False
        with OpenKey(HKEY_CURRENT_USER, steamVRRegEntry) as key:
                (value, type) = QueryValueEx(key, 'Running')
                isRunning = value == 1 # Running: 1 yes, 0 no

        if isRunning:
            print(f'\n   Please exit SteamVR to continue... ')
            while isRunning:
                with OpenKey(HKEY_CURRENT_USER, steamVRRegEntry) as key:
                    (value, type) = QueryValueEx(key, 'Running')
                    isRunning = value == 1
                time.sleep(1)
            print(f'ready.')


        # FIRST FILE
        sourceFile = f"{steam_root}{steamvr_null_driver_settings}"
        if not os.path.islink(sourceFile):
            # if the symlink was not there, we may are being first-time run or there was an update
            if os.path.exists(f"{sourceFile}.headless"):
                os.rename(f"{sourceFile}.headless", f"{sourceFile}.headless_{time.time()}")
            
            # create a copy of the file
            shutil.copy(sourceFile, f"{sourceFile}.headless")

            # edit the copy to be how we want it
            # In the driver_null object, change the enable property value from false to true.
            file_data = {}
            with open(f"{sourceFile}.headless", 'r+') as f:
                data = json.load(f)
                null_body = data['driver_null']
                null_body['enable'] = True
                data['driver_null'] = null_body
                json.dump(data, f, indent=4)
                f.truncate()     # remove remaining part

            if os.path.exists(f"{sourceFile}.original"):
                os.rename(f"{sourceFile}.original", f"{sourceFile}.original_{time.time()}")

            # rename the original file if it does not already exist            
            os.rename (sourceFile, f"{sourceFile}.original")

            # symlink the original
            kdll.CreateSymbolicLinkW(sourceFile, f"{sourceFile}.original", 0)


        # SECOND FILE
        sourceFile = f"{steam_root}{steamvr_resource_settings}"
        if not os.path.islink(sourceFile):
            # if the symlink was not there, we may are being first-time run or there was an update
            if os.path.exists(f"{sourceFile}.headless"):
                os.rename(f"{sourceFile}.headless", f"{sourceFile}.headless_{time.time()}")

            shutil.copy(sourceFile, f"{sourceFile}.headless")

            # edit the copy to be how we want it
            # In the driver_null object, change the enable property value from false to true.
            file_data = {}
            with open(f"{sourceFile}.headless", 'r+') as f:
                data = json.load(f)
                section_body = data['steamvr']
                section_body['requireHmd'] = False
                section_body['forcedDriver'] = "null"
                section_body['activateMultipleDrivers'] = True
                data['steamvr'] = section_body
                json.dump(data, f, indent=4)
                f.truncate()     # remove remaining part

            if os.path.exists(f"{sourceFile}.original"):
                os.rename(f"{sourceFile}.original", f"{sourceFile}.original_{time.time()}")

            # rename the original file if it does not already exist            
            os.rename (sourceFile, f"{sourceFile}.original")

            # symlink the original
            kdll.CreateSymbolicLinkW(sourceFile, f"{sourceFile}.original", 0)


        # which way are we switching? headless => HMD, HMD => headless
        driverSrcFile = f"{steam_root}{steamvr_null_driver_settings}"
        resourceSrcFile = f"{steam_root}{steamvr_resource_settings}"

        if os.readlink(driverSrcFile).endswith('.original'):
            print ('\n   Switching to HEADLESS mode...\n')

            os.remove(driverSrcFile)
            kdll.CreateSymbolicLinkW(driverSrcFile, f"{driverSrcFile}.headless", 0)
            os.remove(resourceSrcFile)
            kdll.CreateSymbolicLinkW(resourceSrcFile, f"{resourceSrcFile}.headless", 0)
        else:
            print ('\n   Switching to HMD mode...\n')

            os.remove(driverSrcFile)
            kdll.CreateSymbolicLinkW(driverSrcFile, f"{driverSrcFile}.original", 0)
            os.remove(resourceSrcFile)
            kdll.CreateSymbolicLinkW(resourceSrcFile, f"{resourceSrcFile}.original", 0)

    
        print('Complete.\n')
        print ("(You may be required to calibrate your setup again)\n")

        print('Restarting SteamVR...\n')
        os.system(f"start {steamVR_launch}")

        time.sleep(10)

    elif ret is None:
        # allowed to enter elevated priviledge mode
        pass
    else:
        # note elevated and elevation request denied
        print ('\n   Elevated permissions are required for this tool for work properly.\n')


# Notes: 
# symlinks -- https://stackoverflow.com/questions/1447575/symlinks-on-windows
# steam registry -- https://steamcommunity.com/discussions/forum/1/1621726179573666840/
# files to change -- https://docs.unrealengine.com/4.26/en-US/AnimatingObjects/SkeletalMeshAnimation/LiveLinkPlugin/Livelinkxr/