pre.js

var Module = {};
var lines = [];
var js_buffer = [];
var pressed_keys = {};
var key_queue = [];

function print_msg(msg) {
  lines.push(msg);
  if (lines.length > 25) 
    lines.shift();
  
  for (var i = 0; i < lines.length; i++) {
    var row = lines[i];
    globalThis.getField("console_"+(25-i-1)).value = row;
  }
}

Module.print = function(msg) {
  let max_len = 80;
  let num_lines = Math.ceil(msg.length / max_len);
  
  for (let i = 0, o = 0; i < num_lines; ++i, o += max_len) {
    print_msg(msg.substr(o, max_len));
  }
}
Module.printErr = function(msg) {
  print_msg(msg);
}

function key_pressed(key_str) {
  if ("WASD".includes(key_str)) {
    key_str = key_str.toLowerCase();
    key_pressed("_") //placeholder for shift;
  }
  let keycode = key_str.charCodeAt(0);
  let doomkey = _key_to_doomkey(keycode);
  print_msg("pressed: " + key_str + " " + keycode + " ");
  if (doomkey === -1) 
    return;

  pressed_keys[doomkey] = 2;
}

function key_down(key_str) {
  let keycode = key_str.charCodeAt(0);
  let doomkey = _key_to_doomkey(keycode);
  print_msg("key down: " + key_str + " " + keycode + " ");
  if (doomkey === -1) 
    return;
  pressed_keys[doomkey] = 1;
}

function key_up(key_str) {
  let keycode = key_str.charCodeAt(0);
  let doomkey = _key_to_doomkey(keycode);
  print_msg("key up: " + key_str + " " + keycode + " ");
  if (doomkey === -1) 
    return;
  pressed_keys[doomkey] = 0;
}

function reset_input_box() {
  globalThis.getField("key_input").value = "Type here for keyboard controls.";
}
app.setInterval("reset_input_box()", 1000);

function write_file(filename, data) {
  let stream = FS.open("/"+filename, "w+");
  FS.write(stream, data, 0, data.length, 0);
  FS.close(stream);
}

function create_framebuffer(width, height) {
  js_buffer = [];
  for (let y=0; y < height; y++) {
    let row = Array(width);
    for (let x=0; x < width; x++) {
      row[x] = "_";
    }
    js_buffer.push(row);
  }
}

function update_framebuffer(framebuffer_ptr, framebuffer_len, width, height) {
  let framebuffer = Module.HEAPU8.subarray(framebuffer_ptr, framebuffer_ptr + framebuffer_len);
  for (let y=0; y < height; y++) {
    let row = js_buffer[y];
    let old_row = row.join("");
    for (let x=0; x < width; x++) {
      let index = (y * width + x) * 4;
      let r = framebuffer[index];
      let g = framebuffer[index+1];
      let b = framebuffer[index+2];
      let avg = (r + g + b) / 3;
      //let avg = (x/width) * 255; // (uncomment for a gradient test)

      //note - these ascii characters were all picked because they have the same width in the sans-serif font that chrome decided to use for text fields
      if (avg > 200)
        row[x] = "_";
      else if (avg > 150)
        row[x] = "::";
      else if (avg > 100)
        row[x] = "?";
      else if (avg > 50)
        row[x] = "//";
      else if (avg > 25)
        row[x] = "b";
      else
        row[x] = "#";
    }
    let row_str = row.join("");
    if (row_str !== old_row)
      globalThis.getField("field_"+(height-y-1)).value = row_str;
  }
}