Category Archives: HTML5

Nebula – a Three.js Experiment

See my Experiment on In order to learn Three.js with WebGL I built this particle experiment. The purpose of this demo is to investigate the performance of WebGL in the browser and to get some nice eye-candy in the process.

To run WebGL you need the latest version of Chrome or Firefox and a machine that is not more than a couple of years old. If you have this and it’s still not working, try restarting your browser.

Note that there is an issue with Three.js on Windows that causes particles not to be scaled – meaning the demo does not look as cool on Windows 🙁

View Demo | Download Source

Why WebGL?

Before anyone mentions it in the comments – no I don’t think WebGL is going to replace Flash any time soon. WebGL is an emerging standard and is not currently supported by many browsers. As such it is not suitable for building client websites. Why I am excited about WebGL is that it offers performance similar to Processing in the browser. On my laptop this demo runs fullscreen at 60FPS.

The Code

Using Three.js is similar to using Away3D or Papervision, indeed some of the code is ported from those engines. To create a 3D view you need a renderer, a camera, a scene and some 3D objects. Each 3D object consists of some geometry and a material. Three.js allows you to choose between a Canvas renderer and a WebGL renderer. The WebGL renderer is many times faster but does not run in as many browsers. The renderer is a normal HTML element and so you can overlay it with other HTML elements. The dot-screen effect is created by overlaying a transparent PNG via CSS background-image.

Nebula is composed of a particle system which loads a particle png material. Note that individual Particles don’t work with the WebGL renderer, you need to use a ParticleSystem. The particle movement is very simple. Particles start at the origin point (0,0,0) and are assigned a random speed. Each frame the particle speed is added to the particle position and the code checks to see if the particle has moved beyond a cutoff distance from the center, in which case it is reset back to the center.

There are also a number of sunbeams which are long skinny 2D planes that use a semi transparent flat color material (MeshBasicMaterial). Set meshes to be doubleSided if you want to see them when they rotate. All materials are set to use AdditiveBlending and depth testing is turned off. This improves performance and gives a nice glowy effect. To avoid the caret text cursor I use Aerotwist’s stop selection snippet. The code uses jQuery purely for handling div resizing and centering. I use requestAnimationFrame as a more polite way to ask for system resources.

The best way to start learning three.js is to download it and browse the examples. Note that examples that load external files such as 3D models need to be run from a local or remote web server. The three.js IRC channel is a good place to hang out and ask questions. Also check out the super-talented Aerotwist‘s great tutorial called “Getting Started with Three.js“.

JavaScript Dev Tools

I’m currently using Aptana Studio 2 for JavaScript development . It’s an Eclipse based IDE with all the associated pros and cons. I personally like Eclipse since I’ve been using it for a while and know the shortcuts. An Eclipse IDE is probably overkill for a loosely typed language such as JS. The one feature I require from a code editor is that it correctly handles indentation and includes automatic code formatting. It’s amazing how many code editors cannot correctly indent the next line when you press return. If anyone knows a good lightweight JS editor that handles indentation properly, I’d love to hear about it.

For debugging JS I use Chrome’s Developer Tools and lots of console.log (it’s the new trace). Chrome’s Dev Tools are similar to Firebug, but I’ve pretty much stopped using Firefox since it seems so slow compared to Chrome.

WebGL for VJing

Nebula from felixturner on Vimeo.

I ended up using this code to build a Video Projection that was shown at the Venice Art Crawl. The text overlay was pulled from live audience tweets sent in to answer the question: “What is the best thing ever?”. The strobe effect was inspired by ‘Enter the Void’ (check this movie out for some truly insane visuals). Thanks to Stan Wiechers for helping out with the Twitter back-end component.

Hopefully this will inspire someone to get started with Three.js and WebGL. Let me know how you get on!

Glitch Your Images with ImageGlitcher

ImageGlitcher allows you to glitch any image and save the result. Glitched images look like they are being displayed on a broken analog TV. Check it out here.

This demo was built using Peter Nitsch’s BitmapData.js – a very useful JS port of ActionScript’s BitmapData class which makes it easy to manipulate canvas image data. After playing around with it for a while I got some pleasing glitched image results, so I figured it would be useful to wrap it up as a little app. The glitch effect is achieved by:

  • Slicing the image horizontally and randomly offsetting the slices
  • Randomly selecting a color channel and offsetting again
  • Brightening the image
  • Adding a ‘scan lines’ overlay.

All the source code is viewable via ‘View Source’. Surprisingly, cross browser development wasn’t too much of a pain once I ignored IE. One of the cool features of HTML5 is native drag and drop support. On Chrome and Firefox you can drag in an image from the desktop.

One issue that came up was that the canvas tag does not allow you to getImageData() on images that are from a different web domain. This is supposedly a security feature to prevent hackers copying images, although I fail to understand why. If a hacker has the URL of an image on your website he already has a local copy of the image – right? Anyway $.getImageData gets around this feature by routing image data through Google App Engine using JSONP.

If I get time there are a few features I want to add in the next version:

  • Add ‘Instagram’ style filters
  • Add more granular filter options
  • Use web workers to avoid hang time

Let me know if you find any issues or if you create any nice images, post a link in the comments.

UPDATED – 9 May 2013

  • Removed loading remote images via $.getImageData. Their service appears to be down.
  • Added additional controls
  • Removed image size limit
  • Improved  messaging

Processing.js Experiment – Noise Field

I built this demo by porting one of my old Processing sketches to the fantastic Processing.js. The demo draws particle trails using Perlin noise to direct the particle motion. Move the mouse to change the noise function and click to randomize the particle drawing parameters.

Processing.js is a JavaScript port of Processing that renders to the HTML5 Canvas tag. It was originally built by the same guy who built jQuery. It’s nice to have a framework for handling common drawing and math functions. As a bonus, if you are familiar with Processing you will be able to jump right in.

Three.js Experiment – Cube Explosion

Had a chance to play with Mr.Doob‘s excellent JavaScript 3D library three.js today and came up with this. Resize your browser down and Refresh to increase performance. Grab the code via ‘View Source…’.

I’m getting ~54 FPS on Chrome, ~43 FPS on Safari and ~30 FPS on FireFox. The iPad gives a sad 7 FPS. To run on IE you will need the Google Chrome Frame Plugin.

There’s definitely a lot of potential in this library.