Prototype & OOP

[espruino-discuss]

Posted at 2014-06-11 by konsumer

I am pretty used to Javascript OOP prototypical programming, but am brand new to Espruino & having some issues. I am making a WS2811 lib, to get my feet wet with Espruino.

function WS2811(len, baud, pin){
  SPI2.setup({baud:baud, mosi:pin});
}

WS2811.prototype.send = function(data){
  SPI2.send4bit(data, 1, 3);
};

// usage

var light = new WS2811(50, 3200000, B15);
light.send([255,0,0, 0,255,0, 0,0,255]);

I get this:

ERROR: Constructor should be a function at line 1 col 6.

If I change the constructor to another form:

var WS2811 = function(len, baud, pin)

I get:
ERROR: Function not found! Skipping. at line 1 col 13

What am I doing wrong?

[espruino-discuss]

Posted at 2014-06-11 by konsumer

Also, as a sidenote, maybe my light string is funny, but even the regular functional form doesn't seem to work right:

SPI2.setup({baud:3200000, mosi:B15});
SPI2.send4bit([255,0,0, 0,255,0, 0,0,255], 0b0001, 0b0011);

It lights up the first LED in a single color or not at all, and that's it.

This is probably related to baude, but maybe should be noted here.

Update: I spoke too soon. I updated the firmware, and it worked like a charm.

SPI2.setup({baud:3200000, mosi:B15});
SPI2.send4bit([255,0,0, 0,255,0, 0,0,255], 1, 3);

sets LEDs 1, 2, &3 to red, green, blue.

Update 2: It seems my code works great after the update, in it's original form. here is the complete lib,if anybody is interested:

/**
 * Simple WS2811 interface
 * @param {Number} interval (100) Milliseconds for update interval
 * @param {Number} len      (50) length of light-string
 * @param {Number} baud     (3200000) bauderate of SPI
 * @param {Pin} pin         (B15) data-pin
 */
function WS2811(interval, len, baud, pin){
  var self = this;
  self.interval = interval ||100;
  self.len = len || 50;
  self.leds = new Uint8Array(self.len * 3);
  SPI2.setup({baud:baud || 3200000, mosi:pin || B15});
  
  self.reset();
  
  // update at interval to copy vals to pixel array
  self.interval = setInterval(function(){
    self.setArray(self.leds);
  }, self.interval);
}

/**
 * Set all pixels to black
 */
WS2811.prototype.reset = function(){
  this.leds = this.leds.map(function(){ return 0; });
};

/**
 * Send array in pixel-friendly format
 * @param {Array} data the pixels in R,G,B,R,G,B,... format
 */
WS2811.prototype.setArray = function(data){
  SPI2.send4bit(data, 1,3);
};

/**
 * Set a pixel to an RGB value
 * @param {Number} i     The pixel ID
 * @param {Array} color  An RGB color, 0-255, in array
 */
WS2811.prototype.setRGB = function(i, color){
  this.leds[i*3    ] = color[0];
  this.leds[i*3 + 1] = color[1];
  this.leds[i*3 + 2] = color[2];
};


// USAGE

var lights = new WS2811();

// scroll all pixels through white colors
function whiteScroll(){
  var pos = 0;
  setInterval(function(){
    pos++;
    for (var i=0; i<lights.leds.length; i+=3){
      var col = (Math.sin(i+pos*0.2)+1) * 127;
      lights.setRGB(i/3, [col,col,col]);
    }
  }, 100);
}


// blink red, green,blue for pixels 1,2,3 to tell us we are starting
// then, run our sequence function
lights.setRGB(0, [255,0,0]);
lights.setRGB(1, [0,255,0]);
lights.setRGB(2, [0,0,255]);
setTimeout(function(){
  lights.reset();
  whiteScroll();
}, 100);

[gfwilliams]

Posted at 2014-06-11 by @gfwilliams

Great, thanks for the update!

Unfortunately most of the rev 1.3 boards ship with firmware that's 6 months old now, and we've fixed and added a massive amount since then!

Out of interest, why didn't you update when you first got the board? Just wondering whether I could have made it more obvious in the Web IDE - obviously it sucks if people's first impressions of Espruino are of something that doesn't quite work correctly! :)

[espruino-discuss]

Posted at 2014-06-11 by konsumer

It was pretty obvious, once I read the docs. I just now had some time to play with it, and pulled it out of a drawer. No fault of the docs, I should have done this, right away. Very impressed. Super-easy to get started.

[espruino-discuss]

Posted at 2014-06-11 by konsumer

As a complete sidenote, I have a lot of experience with native javascript apps. If you guys are interested, I'd be happy to work on a port of the app to a node-webkit standalone. The benefits would be native file access (save files with actual save-file dialog) and no need for chrome install. Is the chrome-only stuff pretty well separated?

[gfwilliams]

Posted at 2014-06-11 by @gfwilliams

@mattbrailsford actually started off with a node-webkit app IIRC. If you've got time it'd be very handy as a way to reduce dependency on Chrome's web store (and Google Logins) - especially if the same code + repo could be used for both Chrome and node-webkit.

Also, an Android port would be epic. It looks like it might be coming to node-webkit soon...

The Web IDE code is at http://www.github.com/espruino/EspruinoWebIDE

It should be relatively well separated now - you'd just need to make a new version of Espruino.Core.Serial that used node-serial for comms, and maybe add some abstraction for load/save file and chrome's configuration stuff.

My ultimate goal would be to allow the Web IDE to be served up from the SD card by Espruino itself :) any changes to make the IDE less dependent on Chrome would really help with that.