splatpost-libusbd

A pixel printer for Splatoon 3's (and Splatoon 2's) drawing/posting feature, using the libusbd library.

Building

(As of right now, requires an Apple Silicon Mac with SIP DISABLED (!! NOT A GOOD IDEA !!) and at least 3 USB-C ports.)

Compile libusbd, then copy libusbd.dylib to this folder and type make to build splatpost-libusbd. Check the libusbd README for information on compatibility and the setup process.

Usage

1. Prepare a 1-bit / 2-colour bitmap of the image you want to use.
2. Use detached joycon or a Pro Controller (or other controller) to start Splatoon 3 and get to the post drawing screen.
3. Disconnect all your controllers (pressing the sync button / disconnecting the cable).
4. Plug your Mac into the Switch with a USB-C to USB-A cable. (currently, libusbd uses the top right port / third port along)
5. Run ./splatpost /path/to/your/bitmap.bmp in a Terminal. Within ~30 minutes maximum, the image should be printed.
   • The image might not start drawing, your Switch still showing the controller connection screen. If this happens, CTRL+C and re-run the command.
   • Sometimes the drawing process can get slightly offset after missing a few inputs. It might help to close everything on your Mac.

For images with more black pixels than white pixels, if you fill the drawing grid with black manually before running, the --invert command line option can be provided to erase white pixels rather than print black pixels.

For Splatoon 2, add --splatoon2 to the command line. Make sure the drawing screen is set to use the smallest pencil, this isn't done automatically.

Typing ./splatpost % will print an example alternating pixel grid.

TODO:

• Fix the "desync" issues where an input or two will be missed, offsetting the whole image.
• More BMP colour modes + dithering
• Faster printing (TSP solving algorithm?)
• More input image files (dithering, PNG?)