Monday, June 15, 2015
Filtering Reality with JavaScript and Google Cardboard
The ability to run virtual reality within a mobile browser is empowering and exciting. Google Cardboard and other similar VR devices make it unbelievably simple, just place your phone into the holder and go! I previously covered Bringing VR to the Web with Google Cardboard and Three.js, where I discussed the basics of building a VR environment that pulls in web data. People really enjoyed that article (and I really enjoyed building that demo) so I thought I'd expand on it with a different idea. Rather than bringing in web APIs, why not bring in your phone's camera and turn this into an Augmented Reality experience?
In this article, I'm going to explore how we can pull in camera data, filter it and display it back using HTML5 and JavaScript. We'll do this all through a stereoscopic vision effect to create an Augmented Reality experience for Google Cardboard and other VR devices. We'll apply a few different filters to our camera stream - a cartoonish greyscale filter, a sepia film style filter, a pixelated filter (my favorite) and an inverse color filter.
If you are completely new to filtering images with HTML5, the canvas tag and JavaScript, I have a whole course on the topic over at Learnable called JavaScript in Motion! I'll be approaching this article with the assumption that you understand the canvas and video tags, along with how to stream videos into the canvas tag. Or with the assumption that you're confident enough to work it out as you go!
Demo code
If you're keen to get straight into the code and try it out, you can find it here on GitHub.
Want to try it in action? I've got a running version hosted here: Reality Filter.
How This Will Work
We'll be taking the same initial set up from the previous Google Cardboard article - a Three.js scene that we display through a stereoscopic effect. That effect allows us to have a display for each eye, making things look wonderfully 3D in VR. However, rather than floating particles and such from the previous article, we remove most elements and place one simple Three.js mesh in front of the camera that plays our camera feed.
Our Code Explained
Looking at our variable declarations, most of the variables here will look familiar to those who've gone through the previous demo. The variables for preparing our Three.js scene, camera, renderer, element for our canvas output, container to place that element in and a variable to store our stereoscopic effect are all the same.
[code language="js"] var scene, camera, renderer, element, container, effect, [/code]Our three new variables related to our camera feed are video, canvas and context.
video- Our actual HTML5<video>element. That will have our camera feed playing within it.canvas- A virtualcanvaselement that will have the contents of ourvideoelement. We will read in the video data from this canvas and then add our theme filters back onto it, before placing its contents into our Three.js scene.context- Ourcanvas' 2D context which we use to perform most functions against it.
We have a few other variables under those which relate to our filter functionality.
[code language="js"] themes = ['blackandwhite', 'sepia', 'arcade', 'inverse'], currentTheme = 0, lookingAtGround = false; [/code]themes- An array of the names of our filters.currentTheme- The index we're currently viewing within thethemesarray.lookingAtGround- Whether or not we've looked at the ground (this one will make more sense soon).
We start with our init() function setting up our scene, camera and so forth as before:
We do not have any camera movement functionality via the DeviceOrientation event this time around. Compared to a VR experience, we won't need to change the actual camera position in this Three.js scene. We're keeping the scene in the same spot - the camera feed is what will be moving when the user looks around.
One listener we have kept from the previous example is an event listener to go fullscreen if we tap the scene. This removes the Chrome address bar from our view.
A Different Use For DeviceOrientationEvent
There is a new use for the DeviceOrientationEvent in this demo. We set it to watch for changes in the orientation of our device and use that as a trigger for switching our filter. We don't really have any physical controls to trigger events, so we control things by where the user is looking. In particular, we change the filter any time the user looks at the ground.
In this code, we watch for whether the evt.gamma is between -1 and 1. If so, they're looking at the ground. This is quite a precise spot on the ground, if you find it too small and difficult to trigger, you can increase the range to between -1.5 and 1.5... etc.
When they are looking in this range and when lookingAtGround is false, we run our theme switcher code. This adjusts currentTheme to the next index number of our themes array. We set lookingAtGround to true and set it back after 4 seconds. This ensures we only change the filter once every four seconds at most.
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by Patrick Catanzariti via SitePoint
A Comprehensive Comparison of WordPress Commenting Plugins
Engagement, engagement, engagement. My brother Lee and I are web developers and entrepreneurs. We try to capitalize on every opportunity available to increase user engagement. A critical part of any strategy aimed at improving user engagement involves allowing users to comment on website articles/blog posts. Commenting is possible on any WordPress site via WordPress’ default commenting functionality or by installing a third party plugin. However, WordPress’ default commenting lacks some important features that tend to increase user interaction. It also requires the installation of the Akismet plugin to keep your site’s comments spam free. In addition, there was recent news uncovering a cross site scripting bug (the 0 Day Bug) in WordPress’ commenting when Akismet is absent (but a patch has been released). For these reasons, we opt for alternatives to WordPress’ default commenting functionality. We researched four popular third party commenting plugins: Disqus, Facebook, Livefyre and Google Plus. We delved into the user and admin features offered by each plugin, their configuration processes, and some shortcomings to provide an in depth comparison of your options.
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by Ben Shadle via SitePoint
Cardiff Comedy Festival
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Boxing up your Apps as Phars Quickly and Easily with Box
In this tutorial, we’ll use Box to package a PHP application into a Phar, in order to make it easily distributable and globally installable via Composer. We’ll also learn how to distribute it so that it’s installable via Composer.
On what?
We need a project for this, and packaging up yet another “Hello World” script would be pointless. We’ll use Webiny’s FolderBuilder, a tool which you can use to plan out the folder structure for your project, interactively drag and drop files and folders, and even export and share these structures with others.
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by Bruno Skvorc via SitePoint
How to Work Content Marketing Like Paul Jarvis
This post was originally published on Paul Jarvis’ Medium blog, which you can find here. People call me a “content marketer” often (not sure if it’s a compliment or insult), so let’s talk about how you can use the articles you write to sell the products or service you’ve got. Too often, clients, friends, and […]
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by Paul Jarvis via SitePoint