bangle-trex.js

/* This is a simple T-Rex JavaScript game 
for the Bangle.js smartwatch.

Check it out on:
https://www.kickstarter.com/projects/gfw/banglejs-the-hackable-smart-watch

You're seeing T-Rex's JavaScript running in an 
emulated version of the Espruino JavaScript
interpreter, compiled with emscripten and 
running in JavaScript directly on your web 
browser.

The REPL on the left isn't your browser's
REPL. It's the REPL of the interpreted
Espruino JS engine.

*/

greal = g;
g.clear();
g = Graphics.createArrayBuffer(120,64,1,{msb:true});
g.flip = function() {
  greal.drawImage({
    width:120,
    height:64,
    buffer:g.buffer
  },0,(240-128)/2,{scale:2});
};
var W = g.getWidth();
var BTNL = BTN4;
var BTNR = BTN5;
var BTNU = BTN1;

// Images can be added like this in Espruino v2.00
var IMG = {
  rex: [Graphics.createImage(`
           ########
          ##########
          ## #######
          ##########
          ##########
          ##########
          #####
          ########
#        #####
#      #######
##    ##########
###  ######### #
##############
##############
 ############
  ###########
   #########
    #######
     ### ##
     ##   #
          #
          ##
`),Graphics.createImage(`
           ########
          ##########
          ## #######
          ##########
          ##########
          ##########
          #####
          ########
#        #####
#      #######
##    ##########
###  ######### #
##############
##############
 ############
  ###########
   #########
    #######
     ### ##
     ##   ##
     #
     ##
`),Graphics.createImage(`
           ########
          #   ######
          # # ######
          #   ######
          ##########
          ##########
          #####
          ########
#        #####
#      #######
##    ##########
###  ######### #
##############
##############
 ############
  ###########
   #########
    #######
     ### ##
     ##   #
     #    #
     ##   ##
`)],
  cacti: [Graphics.createImage(`
     ##
    ####
    ####
    ####
    ####
    ####  #
 #  #### ###
### #### ###
### #### ###
### #### ###
### #### ###
### #### ###
### #### ###
### #### ###
###########
 #########
    ####
    ####
    ####
    ####
    ####
    ####
    ####
    ####
`),Graphics.createImage(`
   ##
   ##
 # ##
## ##  #
## ##  #
## ##  #
## ##  #
#####  #
 ####  #
   #####
   ####
   ##
   ##
   ##
   ##
   ##
   ##
   ##
`)],
};
IMG.rex.forEach(i=>i.transparent=0);
IMG.cacti.forEach(i=>i.transparent=0);
var cacti, rex, frame;

function gameStart() {
  rex = {
    alive : true,
    img : 0,
    x : 10, y : 0,
    vy : 0,
    score : 0
  };
  cacti = [ { x:W, img:1 } ];
  var random = new Uint8Array(128*3/8);
  for (var i=0;i<50;i++) {
    var a = 0|(Math.random()*random.length);
    var b = 0|(Math.random()*8);
    random[a]|=1<<b;
  }
  IMG.ground = { width: 128, height: 3, bpp : 1, buffer : random.buffer };
  frame = 0;
  setInterval(onFrame, 50);
}
function gameStop() {
  rex.alive = false;
  rex.img = 2; // dead
  clearInterval();
  setTimeout(function() {
    setWatch(gameStart, BTNU, {repeat:0,debounce:50,edge:"rising"});
  }, 1000);
  setTimeout(onFrame, 10);
}

function onFrame() {
  g.clear();
  if (rex.alive) {
    frame++;
    rex.score++;
    if (!(frame&3)) rex.img = rex.img?0:1;
    // move rex
    if (BTNL.read() && rex.x>0) rex.x--;
    if (BTNR.read() && rex.x<20) rex.x++;
    if (BTNU.read() && rex.y==0) rex.vy=4;
    rex.y += rex.vy;
    rex.vy -= 0.2;
    if (rex.y<=0) {rex.y=0; rex.vy=0; }
    // move cacti
    var lastCactix = cacti.length?cacti[cacti.length-1].x:W-1;
    if (lastCactix<W) {
      cacti.push({
        x : lastCactix + 24 + Math.random()*W,
        img : (Math.random()>0.5)?1:0
      });
    }
    cacti.forEach(c=>c.x--);
    while (cacti.length && cacti[0].x<0) cacti.shift();
  } else {
    g.drawString("Game Over!",(W-g.stringWidth("Game Over!"))/2,20);
  }
  g.drawLine(0,60,239,60);
  cacti.forEach(c=>g.drawImage(IMG.cacti[c.img],c.x,60-IMG.cacti[c.img].height));
  // check against actual pixels
  var rexx = rex.x;
  var rexy = 38-rex.y;
  if (rex.alive &&
     (g.getPixel(rexx+0, rexy+13) ||
      g.getPixel(rexx+2, rexy+15) ||
      g.getPixel(rexx+5, rexy+19) ||
      g.getPixel(rexx+10, rexy+19) ||
      g.getPixel(rexx+12, rexy+15) ||
      g.getPixel(rexx+13, rexy+13) ||
      g.getPixel(rexx+15, rexy+11) ||
      g.getPixel(rexx+17, rexy+7) ||
      g.getPixel(rexx+19, rexy+5) ||
      g.getPixel(rexx+19, rexy+1))) {
    return gameStop();
  }
  g.drawImage(IMG.rex[rex.img], rexx, rexy);
  var groundOffset = frame&127;
  g.drawImage(IMG.ground, -groundOffset, 61);
  g.drawImage(IMG.ground, 128-groundOffset, 61);
  g.drawString(rex.score,(W-1)-g.stringWidth(rex.score));
  g.flip();
}

gameStart();