er-patcher/er-patcher

#!/usr/bin/env python3

import os
import sys
import subprocess
import argparse
from pathlib import Path
import struct


if __name__ == "__main__":

    patcher_args = sys.argv[1:sys.argv.index("--")]
    
    parser = argparse.ArgumentParser(description="Patch Elden Ring executable and launch it without EAC.")
    parser.add_argument("-r", "--rate", type=int, default=60, help="Modify the frame rate limit (e.g. 30, 120, 165 or whatever).")
    parser.add_argument("-u", "--ultrawide", action=argparse.BooleanOptionalAction, help="Removes black bars when using a resolution with an aspect ratio other than 16:9.")
    parser.add_argument("-v", "--disable-vigniette", action=argparse.BooleanOptionalAction, help="Disables the vigniette overlay.")
    patch = parser.parse_args(patcher_args)

    exe_name = Path("eldenring.exe")
    with open(exe_name, "rb") as f:
        exe = f.read()
    exe_hex = exe.hex()

    if patch.rate != 60 and patch.rate > 0:
        exe_hex = exe_hex.replace(
            "c743208988883ceb43897318ebca897318",
            "c743208988883ceb43897318ebca897318".replace(
                "8988883c", struct.pack('<f', 1 / patch.rate).hex()
            )
        )

    if patch.ultrawide:
        exe_hex = exe_hex.replace(
            "8b0185c07442448b5904",
            "8b0185c0eb42448b5904"
        )

    if patch.disable_vigniette:
        exe_hex = exe_hex.replace(
            "f30f590514a76e01f3440f5cc8f3450f5ecb",
            "f30f590524b56e01f3440f5cc8f3450f5ecb"
        )
    
    patched_exe_dir = Path("./er-patcher-tmp")
    if not patched_exe_dir.is_dir():
        patched_exe_dir.mkdir()

    with open(patched_exe_dir / exe_name, "wb") as f:
        f.write(bytes.fromhex(exe_hex))

    # start patched exe directly to avoid EAC
    steam_cmd = sys.argv[1 + sys.argv.index("--"):]
    steam_cmd[-1] = Path(steam_cmd[-1]).parent.absolute() / patched_exe_dir / exe_name
    subprocess.run(steam_cmd)

    os.remove(patched_exe_dir / exe_name)
    os.rmdir(patched_exe_dir)