Feeding data to xidi externally

[joao678]

As previously discussed in #74, I've made an attempt at replacing xinput with SDL2 to allow for more controllers (or anything really) to feed data to xidi, but concerns were raised about the possibility of using SDL2 since SDL2 uses DirectInput calls itself that HookModule already uses.
I can show another solution to this problem, this time allowing pretty much any external program to feed data to xidi without making it load SDL2 or any other dependency

Here's the branch: https://github.com/joao678/Xidi/tree/json

How it works: Xidi reads a memory mapped file written by another program and it fills the virtual controller state with the data recieved. On the xidi side cJSON is used (it's just two files), xidi recieves a json from another program for example, a python script that reads a sdl controller

import time
import sdl2
import mmap
import json

BUF_SIZE = 1000000
SHARED_MEM_NAME = "Local\\XidiControllers"

sdl2.SDL_Init(sdl2.SDL_INIT_GAMECONTROLLER)
ctrl = sdl2.SDL_GameControllerOpen(0)

mm = mmap.mmap(-1, BUF_SIZE, tagname=SHARED_MEM_NAME)

def remap(value, fromMin, fromMax, toMin, toMax):
    return toMin + (value - fromMin) * (toMax - toMin) / (fromMax - fromMin)

def send_data_to_xidi(message):
    mm.seek(0)
    mm.write((message + "\x00").encode())

def update():
    sdl2.SDL_GameControllerUpdate()
    
    controllers = [{
        "b1" : sdl2.SDL_GameControllerGetButton(ctrl, sdl2.gamecontroller.SDL_CONTROLLER_BUTTON_A),
        "b2" : sdl2.SDL_GameControllerGetButton(ctrl, sdl2.gamecontroller.SDL_CONTROLLER_BUTTON_B),
        "b3" : sdl2.SDL_GameControllerGetButton(ctrl, sdl2.gamecontroller.SDL_CONTROLLER_BUTTON_X),
        "b4" : sdl2.SDL_GameControllerGetButton(ctrl, sdl2.gamecontroller.SDL_CONTROLLER_BUTTON_Y),
        "b5" : sdl2.SDL_GameControllerGetButton(ctrl, sdl2.gamecontroller.SDL_CONTROLLER_BUTTON_LEFTSHOULDER),
        "b6" : sdl2.SDL_GameControllerGetButton(ctrl, sdl2.gamecontroller.SDL_CONTROLLER_BUTTON_RIGHTSHOULDER),
        "b7" : int(sdl2.SDL_GameControllerGetAxis(ctrl, sdl2.gamecontroller.SDL_CONTROLLER_AXIS_TRIGGERLEFT) > (32767 / 2)),
        "b8" : int(sdl2.SDL_GameControllerGetAxis(ctrl, sdl2.gamecontroller.SDL_CONTROLLER_AXIS_TRIGGERRIGHT) > (32767 / 2)),
        "b9" : sdl2.SDL_GameControllerGetButton(ctrl, sdl2.gamecontroller.SDL_CONTROLLER_BUTTON_BACK),
        "b10" : sdl2.SDL_GameControllerGetButton(ctrl, sdl2.gamecontroller.SDL_CONTROLLER_BUTTON_START),
        "b11" : sdl2.SDL_GameControllerGetButton(ctrl, sdl2.gamecontroller.SDL_CONTROLLER_BUTTON_LEFTSTICK),
        "b12" : sdl2.SDL_GameControllerGetButton(ctrl, sdl2.gamecontroller.SDL_CONTROLLER_BUTTON_RIGHTSTICK),
        "b13" : 0,
        "b14" : 0,
        "b15" : 0,
        "b16" : 0,
        "X" : remap(sdl2.SDL_GameControllerGetAxis(ctrl, sdl2.gamecontroller.SDL_CONTROLLER_AXIS_LEFTX), -32768, 32767, 0, 65535),
        "Y" : remap(sdl2.SDL_GameControllerGetAxis(ctrl, sdl2.gamecontroller.SDL_CONTROLLER_AXIS_LEFTY), -32768, 32767, 0, 65535),
        "Z" : remap(sdl2.SDL_GameControllerGetAxis(ctrl, sdl2.gamecontroller.SDL_CONTROLLER_AXIS_RIGHTX), -32768, 32767, 0, 65535),
        "RotX" : 0,
        "RotY" : 0,
        "RotZ" : remap(sdl2.SDL_GameControllerGetAxis(ctrl, sdl2.gamecontroller.SDL_CONTROLLER_AXIS_RIGHTY), -32768, 32767, 0, 65535),
        "Up" : sdl2.SDL_GameControllerGetButton(ctrl, sdl2.gamecontroller.SDL_CONTROLLER_BUTTON_DPAD_UP),
        "Down" : sdl2.SDL_GameControllerGetButton(ctrl, sdl2.gamecontroller.SDL_CONTROLLER_BUTTON_DPAD_DOWN),
        "Left" : sdl2.SDL_GameControllerGetButton(ctrl, sdl2.gamecontroller.SDL_CONTROLLER_BUTTON_DPAD_LEFT),
        "Right" : sdl2.SDL_GameControllerGetButton(ctrl, sdl2.gamecontroller.SDL_CONTROLLER_BUTTON_DPAD_RIGHT)
    }, {
        "b1" : sdl2.SDL_GameControllerGetButton(ctrl, sdl2.gamecontroller.SDL_CONTROLLER_BUTTON_A),
        "b2" : sdl2.SDL_GameControllerGetButton(ctrl, sdl2.gamecontroller.SDL_CONTROLLER_BUTTON_B),
        "b3" : sdl2.SDL_GameControllerGetButton(ctrl, sdl2.gamecontroller.SDL_CONTROLLER_BUTTON_X),
        "b4" : sdl2.SDL_GameControllerGetButton(ctrl, sdl2.gamecontroller.SDL_CONTROLLER_BUTTON_Y),
        "b5" : sdl2.SDL_GameControllerGetButton(ctrl, sdl2.gamecontroller.SDL_CONTROLLER_BUTTON_LEFTSHOULDER),
        "b6" : sdl2.SDL_GameControllerGetButton(ctrl, sdl2.gamecontroller.SDL_CONTROLLER_BUTTON_RIGHTSHOULDER),
        "b7" : int(sdl2.SDL_GameControllerGetAxis(ctrl, sdl2.gamecontroller.SDL_CONTROLLER_AXIS_TRIGGERLEFT) > (32767 / 2)),
        "b8" : int(sdl2.SDL_GameControllerGetAxis(ctrl, sdl2.gamecontroller.SDL_CONTROLLER_AXIS_TRIGGERRIGHT) > (32767 / 2)),
        "b9" : sdl2.SDL_GameControllerGetButton(ctrl, sdl2.gamecontroller.SDL_CONTROLLER_BUTTON_BACK),
        "b10" : sdl2.SDL_GameControllerGetButton(ctrl, sdl2.gamecontroller.SDL_CONTROLLER_BUTTON_START),
        "b11" : sdl2.SDL_GameControllerGetButton(ctrl, sdl2.gamecontroller.SDL_CONTROLLER_BUTTON_LEFTSTICK),
        "b12" : sdl2.SDL_GameControllerGetButton(ctrl, sdl2.gamecontroller.SDL_CONTROLLER_BUTTON_RIGHTSTICK),
        "b13" : 0,
        "b14" : 0,
        "b15" : 0,
        "b16" : 0,
        "X" : remap(sdl2.SDL_GameControllerGetAxis(ctrl, sdl2.gamecontroller.SDL_CONTROLLER_AXIS_LEFTX), -32768, 32767, 0, 65535),
        "Y" : remap(sdl2.SDL_GameControllerGetAxis(ctrl, sdl2.gamecontroller.SDL_CONTROLLER_AXIS_LEFTY), -32768, 32767, 0, 65535),
        "Z" : remap(sdl2.SDL_GameControllerGetAxis(ctrl, sdl2.gamecontroller.SDL_CONTROLLER_AXIS_RIGHTX), -32768, 32767, 0, 65535),
        "RotX" : 0,
        "RotY" : 0,
        "RotZ" : remap(sdl2.SDL_GameControllerGetAxis(ctrl, sdl2.gamecontroller.SDL_CONTROLLER_AXIS_RIGHTY), -32768, 32767, 0, 65535),
        "Up" : sdl2.SDL_GameControllerGetButton(ctrl, sdl2.gamecontroller.SDL_CONTROLLER_BUTTON_DPAD_UP),
        "Down" : sdl2.SDL_GameControllerGetButton(ctrl, sdl2.gamecontroller.SDL_CONTROLLER_BUTTON_DPAD_DOWN),
        "Left" : sdl2.SDL_GameControllerGetButton(ctrl, sdl2.gamecontroller.SDL_CONTROLLER_BUTTON_DPAD_LEFT),
        "Right" : sdl2.SDL_GameControllerGetButton(ctrl, sdl2.gamecontroller.SDL_CONTROLLER_BUTTON_DPAD_RIGHT)
    }, {
        "b1" : sdl2.SDL_GameControllerGetButton(ctrl, sdl2.gamecontroller.SDL_CONTROLLER_BUTTON_A),
        "b2" : sdl2.SDL_GameControllerGetButton(ctrl, sdl2.gamecontroller.SDL_CONTROLLER_BUTTON_B),
        "b3" : sdl2.SDL_GameControllerGetButton(ctrl, sdl2.gamecontroller.SDL_CONTROLLER_BUTTON_X),
        "b4" : sdl2.SDL_GameControllerGetButton(ctrl, sdl2.gamecontroller.SDL_CONTROLLER_BUTTON_Y),
        "b5" : sdl2.SDL_GameControllerGetButton(ctrl, sdl2.gamecontroller.SDL_CONTROLLER_BUTTON_LEFTSHOULDER),
        "b6" : sdl2.SDL_GameControllerGetButton(ctrl, sdl2.gamecontroller.SDL_CONTROLLER_BUTTON_RIGHTSHOULDER),
        "b7" : int(sdl2.SDL_GameControllerGetAxis(ctrl, sdl2.gamecontroller.SDL_CONTROLLER_AXIS_TRIGGERLEFT) > (32767 / 2)),
        "b8" : int(sdl2.SDL_GameControllerGetAxis(ctrl, sdl2.gamecontroller.SDL_CONTROLLER_AXIS_TRIGGERRIGHT) > (32767 / 2)),
        "b9" : sdl2.SDL_GameControllerGetButton(ctrl, sdl2.gamecontroller.SDL_CONTROLLER_BUTTON_BACK),
        "b10" : sdl2.SDL_GameControllerGetButton(ctrl, sdl2.gamecontroller.SDL_CONTROLLER_BUTTON_START),
        "b11" : sdl2.SDL_GameControllerGetButton(ctrl, sdl2.gamecontroller.SDL_CONTROLLER_BUTTON_LEFTSTICK),
        "b12" : sdl2.SDL_GameControllerGetButton(ctrl, sdl2.gamecontroller.SDL_CONTROLLER_BUTTON_RIGHTSTICK),
        "b13" : 0,
        "b14" : 0,
        "b15" : 0,
        "b16" : 0,
        "X" : remap(sdl2.SDL_GameControllerGetAxis(ctrl, sdl2.gamecontroller.SDL_CONTROLLER_AXIS_LEFTX), -32768, 32767, 0, 65535),
        "Y" : remap(sdl2.SDL_GameControllerGetAxis(ctrl, sdl2.gamecontroller.SDL_CONTROLLER_AXIS_LEFTY), -32768, 32767, 0, 65535),
        "Z" : remap(sdl2.SDL_GameControllerGetAxis(ctrl, sdl2.gamecontroller.SDL_CONTROLLER_AXIS_RIGHTX), -32768, 32767, 0, 65535),
        "RotX" : 0,
        "RotY" : 0,
        "RotZ" : remap(sdl2.SDL_GameControllerGetAxis(ctrl, sdl2.gamecontroller.SDL_CONTROLLER_AXIS_RIGHTY), -32768, 32767, 0, 65535),
        "Up" : sdl2.SDL_GameControllerGetButton(ctrl, sdl2.gamecontroller.SDL_CONTROLLER_BUTTON_DPAD_UP),
        "Down" : sdl2.SDL_GameControllerGetButton(ctrl, sdl2.gamecontroller.SDL_CONTROLLER_BUTTON_DPAD_DOWN),
        "Left" : sdl2.SDL_GameControllerGetButton(ctrl, sdl2.gamecontroller.SDL_CONTROLLER_BUTTON_DPAD_LEFT),
        "Right" : sdl2.SDL_GameControllerGetButton(ctrl, sdl2.gamecontroller.SDL_CONTROLLER_BUTTON_DPAD_RIGHT)
    }, {
        "b1" : sdl2.SDL_GameControllerGetButton(ctrl, sdl2.gamecontroller.SDL_CONTROLLER_BUTTON_A),
        "b2" : sdl2.SDL_GameControllerGetButton(ctrl, sdl2.gamecontroller.SDL_CONTROLLER_BUTTON_B),
        "b3" : sdl2.SDL_GameControllerGetButton(ctrl, sdl2.gamecontroller.SDL_CONTROLLER_BUTTON_X),
        "b4" : sdl2.SDL_GameControllerGetButton(ctrl, sdl2.gamecontroller.SDL_CONTROLLER_BUTTON_Y),
        "b5" : sdl2.SDL_GameControllerGetButton(ctrl, sdl2.gamecontroller.SDL_CONTROLLER_BUTTON_LEFTSHOULDER),
        "b6" : sdl2.SDL_GameControllerGetButton(ctrl, sdl2.gamecontroller.SDL_CONTROLLER_BUTTON_RIGHTSHOULDER),
        "b7" : int(sdl2.SDL_GameControllerGetAxis(ctrl, sdl2.gamecontroller.SDL_CONTROLLER_AXIS_TRIGGERLEFT) > (32767 / 2)),
        "b8" : int(sdl2.SDL_GameControllerGetAxis(ctrl, sdl2.gamecontroller.SDL_CONTROLLER_AXIS_TRIGGERRIGHT) > (32767 / 2)),
        "b9" : sdl2.SDL_GameControllerGetButton(ctrl, sdl2.gamecontroller.SDL_CONTROLLER_BUTTON_BACK),
        "b10" : sdl2.SDL_GameControllerGetButton(ctrl, sdl2.gamecontroller.SDL_CONTROLLER_BUTTON_START),
        "b11" : sdl2.SDL_GameControllerGetButton(ctrl, sdl2.gamecontroller.SDL_CONTROLLER_BUTTON_LEFTSTICK),
        "b12" : sdl2.SDL_GameControllerGetButton(ctrl, sdl2.gamecontroller.SDL_CONTROLLER_BUTTON_RIGHTSTICK),
        "b13" : 0,
        "b14" : 0,
        "b15" : 0,
        "b16" : 0,
        "X" : remap(sdl2.SDL_GameControllerGetAxis(ctrl, sdl2.gamecontroller.SDL_CONTROLLER_AXIS_LEFTX), -32768, 32767, 0, 65535),
        "Y" : remap(sdl2.SDL_GameControllerGetAxis(ctrl, sdl2.gamecontroller.SDL_CONTROLLER_AXIS_LEFTY), -32768, 32767, 0, 65535),
        "Z" : remap(sdl2.SDL_GameControllerGetAxis(ctrl, sdl2.gamecontroller.SDL_CONTROLLER_AXIS_RIGHTX), -32768, 32767, 0, 65535),
        "RotX" : 0,
        "RotY" : 0,
        "RotZ" : remap(sdl2.SDL_GameControllerGetAxis(ctrl, sdl2.gamecontroller.SDL_CONTROLLER_AXIS_RIGHTY), -32768, 32767, 0, 65535),
        "Up" : sdl2.SDL_GameControllerGetButton(ctrl, sdl2.gamecontroller.SDL_CONTROLLER_BUTTON_DPAD_UP),
        "Down" : sdl2.SDL_GameControllerGetButton(ctrl, sdl2.gamecontroller.SDL_CONTROLLER_BUTTON_DPAD_DOWN),
        "Left" : sdl2.SDL_GameControllerGetButton(ctrl, sdl2.gamecontroller.SDL_CONTROLLER_BUTTON_DPAD_LEFT),
        "Right" : sdl2.SDL_GameControllerGetButton(ctrl, sdl2.gamecontroller.SDL_CONTROLLER_BUTTON_DPAD_RIGHT)
    }]

    send_data_to_xidi(json.dumps(controllers))
    time.sleep(0.01)

while True:
    update()

in this other example a HTML file with a canvas is created that sends data to a websocket server with python, I can open this page on my phone from the local network and send the commands from my phone to xidi for example

import asyncio
import websockets
import mmap

BUF_SIZE = 1000000
SHARED_MEM_NAME = "Local\\XidiControllers"

mm = mmap.mmap(-1, BUF_SIZE, tagname=SHARED_MEM_NAME)

def remap(value, fromMin, fromMax, toMin, toMax):
    return toMin + (value - fromMin) * (toMax - toMin) / (fromMax - fromMin)

def send_data_to_xidi(message):
    mm.seek(0)
    mm.write((message + "\x00").encode())

async def handle_client(websocket, path):
    async for message in websocket:
        send_data_to_xidi(message)

start_server = websockets.serve(handle_client, "local_machine_ip_here", 8765)

asyncio.get_event_loop().run_until_complete(start_server)
asyncio.get_event_loop().run_forever()

This approach decouples SDL from xidi and allows it to work as intended, with the added option of reading data externally

[samuelgr]

This is a really cool idea, thanks so much for sharing it!

The SDL part itself is already quite interesting. Thinking even beyond that, it is entirely conceivable that one of Xidi's future modular back-ends could be an IPC back-end so that any type of external application could provide Xidi with physical controller data. Anyone could write their own application or script and Xidi would take the data as physical controller input, which could then get piped to the application via DirectInput.

[joao678]

Cool right? I've tried a lot of things before and and memory mapped files seems to be the way to go.
I haven't noticed any crazy CPU usage spikes or memory leaks while the game is running, all other methods I've tried such as TCP or UDP networking whould cause massive amounts of lag on both input or the game's FPS and things like lua scripting whould cause crashes or potential conflicts.
I forgot to mention, I've tested both dinput8 and winmm with FlatOut2 and snes9x respectively and both work fine.
Even if you're planning a much more elaborate system for a modular backend, if you need data to be read externally, I'd consider this method 😉