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.

``js
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/examples/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:

`rust
#[no_mangle]
pub extern "C" fn alloc_app(rng_seed: usize, storage_buf: const u8, storage_len: usize) -> mut c_void {
// Called once during initialisation.
// seed is a random integer created using Math.random(), which can be used
// as a seed for an rng.
// storage_buf and storage_len is an address and size suitable for passing to
// prototty_wasm::WasmStorage::from_ptr.
// Allocate your application's state, and return a raw pointer to it.
}

#[no_mangle]
pub fn tick(app: *mut c_void,
input_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.
// input_buffer is a buffer containing encoded input values
// 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.
}
``