https://github.com/Armael/pixels

a shared pixel display controllable via TCP
https://github.com/Armael/pixels

Last synced: 3 months ago
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a shared pixel display controllable via TCP

• Host: GitHub
• URL: https://github.com/Armael/pixels
• Owner: Armael
• Created: 2023-01-19T18:01:03.000Z (almost 2 years ago)
• Default Branch: main
• Last Pushed: 2024-01-25T14:51:19.000Z (10 months ago)
• Last Synced: 2024-05-31T10:40:53.244Z (6 months ago)
• Language: OCaml
• Homepage:
• Size: 26.4 KB
• Stars: 13
• Watchers: 2
• Forks: 1
• Open Issues: 0
• Metadata Files:
  • Readme: README.md

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README

        
# a shared pixel display controllable via TCP

Dependencies: ocaml 5.0, `tsdl`

``` sh

$ dune exec -- server/localnet/server.exe

# in another terminal, try one of the basic clients:

$ dune exec -- client/client.exe

# or go write your own!

```

Pass `--help` to the server binary for additional settings.

## protocol

The server expects TCP packets. An TCP packet should contain one or several

concatenated *pixel commands*. A pixel command consists of 7 bytes, and tells

the server to draw one colored pixel:

```

 XX YY R G B 

```

- `XX`: a 16 bits big-endian integer for the `x` coordinate of the pixel

- `YY`: a 16 bits big-endian integer for the `y` coordinate of the pixel

- `R`, `G`, `B`: the color of the pixel (the red, green, blue component 

  respectively)

## anti-spam measures (for `server/localnet`)

The localnet server implements some basic rate-limiting / anti-spam measures

based on the client IP address, tweakable using the `--nb-clients` and

`--max-age` options of the server.

- there is a limit on the number of visible pixels sent by the same client;

  after this limit, oldest pixels get removed first. If `--nb-clients` (an

  estimation of the number of simultaneous clients) is `N` and the total number

  of pixels of the screen is `S`, then the per-client limit is `S / N`.

- pixels decay and disappear after some time (set by `--max-age`).

## separate receiver/display

The `server/receiver` and `server/display` components are an alternative to

`server/localnet`.

They make it possible to decouple listening for clients and displaying. The

receiver (contacted by clients and receiving pixels packets) can be put on a

different computer than the display. The output of the receiver should be piped

into the input of the display component, which can e.g. be done through ssh.

Example usage:

```

scp _build/default/server/receiver/receiver.exe you@yourserver

ssh you@yourserver ./receiver.exe | dune exec -- server/display/display.exe

```

*NB*: be aware that ^C-ing the ssh command will not automatically terminate the

receiver process on the remote server, you may have to kill it separately.