Prototty JS App Harness

Prototty is a rust library for rendering to a terminal, designed specifically with game prototyping in mind. It supports compiling to web assembly. This library provides an application harness, that takes a compiled web assembly file, and runs it, passing through keyboard input, and rendering the output to the screen.

Example

This runs an app in a file called "wasm_app.wasm", rendering the output into an element called "protottyTerminal", using a grid of 30x20 cells.

import prototty from 'prototty-terminal-js';

let node = document.getElementById("protottyTerminal");
prototty.loadProtottyApp("wasm_app.wasm", 30, 20, node).then(app => app.start());

Big Example

https://github.com/stevebob/protrotty-tetris

This is an implementation of tetris. There's a unix app that runs in an ansi terminal, and a wasm app which runs in a browser using this library.

Interface

The app harness expects the following functions to be exposed by the wasm blob:

#[no_mangle]
pub extern "C" fn alloc_app(rng_seed: usize) -> *mut c_void {
    // Called once during initialisation.
    // Allocate your application's state, and return a raw pointer to it.
}

#[no_mangle]
pub fn tick(app: *mut c_void,
            key_code_buffer: *const u8,
            key_mod_buffer: *const u8,
            num_inputs: usize,
            period_millis: f64) {

    // Called by the app harness once per frame.
    // `app` is a pointer to your application's state, returned by `alloc_app`.
    // `key_code_buffer` is a buffer containing `event.keyCode` values of keypress events since the last frame.
    // `key_mod_buffer` is a buffer of bytes describing modifier keys:
    //    bit 0 is set <=> shift is pressed
    // `num_inputs` is the number of keycodes in `which_buffer` and `key_code_buffer`.
    // `period_millis` is the number of milliseconds that have passed since the last call to `tick`.
}