HTML5

When it comes the the world wide web, HTML5 seems to be the obvious way forward, we have been hearing about it for years and although all mainstream browsers support it to various extents it is still under development and it will likely be years until its specifications are agreed upon and finalized as a standard.

HTML5 is the fifth revision of the HTML standard where not only are web-designers and developers are allowed to resume working on all previous functionality offered through HTML4 but also natively include standard APIs which when thinking back should have been implemented decades ago.

A case in point is video streaming, for the past decade we have all been viewing online streamed videos mainly on youtube through Flash, this makes no technical sense, flash was intended for embed-able interactive animations, was then creatively used to create online games which finally lead to video streaming. The only reason all the big companies started streaming videos through Flash was because there was no other option, a huge percentage of the internet population had flash installed and therefor was their only option. With HTML5 gone are the days of using proprietary software, downloading and installing plugins only to view mediocre video quality. The <video> tag is all you need, and it is already bundled up with most mainstream browsers.

Another case in point is storage, for as long as I can remember us developers had to make due with cookies to provide our users with a feeling of "stateful-ness" over a stateless protocol where every page flowed smoothly to the next page as if they're using a simple application. Because of the limitations available when using cookies (KBs) we would bounce off a unique session id in a cookie with each request to the server for the server to know who the request is coming from and in what state the client (browser) is. Not only is this very insecure, the entire state for each client has to be maintained on the server. With HTML5 the browser has access to various MBs of storage for each domain name (depends on browser) which not only can be used to store client state but also allow for temporary offline availability to the application. Not only does this allow development for much smother applications it also shifts the state from the server down to the client effectively shifting some of the load which should have never have been on the server back down to the client. This results in fewer HTTP requests to the server allowing the server to serve more clients on the same hardware. A win-win situation.

Some obviously missing APIs have also been included, we have all seen tons of java-script code to add drag-and-drop functionality to a web application, which although one can find some good implementations such as the jQuery framework the overhead involved for such a nowadays common way of interacting with a computer. HTML5 provides an API just for drag-and-drop operations allowing for less javascript and more browser compatibility.

Speaking about compatibility, we were all introduced to a neat little site which will rate your current browser from 0 to 400 depending on how much of HTML5 is already supported. Chrome 12 ranked 314

Whilst my iPhone's safari browser ranked 217 which is not bad for a mobile browser.

Some other widely spoken about HTML5 APIs include

• Canvas - allowing for 2d drawing
• Cross Document Messaging - allowing for messaging between different open pages
• Microdata - enhancing the contents on the page to aid search engines and crawlers to easily parse and index the pages.

I'm sure there are hundreds of other interesting features and APIs offered by HTML5 and if I had to list them all this blog post will run into tens of thousands of words and I would never be able to push the "PUBLISH POST" just below the blogger editor ;)

Second Life - Scripting (LSL)

During our previous session we focused on constructing virtual objects by linking multiple prims to form a single object but there's more to SecondLife objects than just creating static objects that do nothing but let Avatars sit on them. We can add interactivity to any object by embedding LSL (Linden Script Language) scripts in our objects. This post will focus on demonstrating some of the functionality available through this scripting language.

LSL syntax is very similar to javascript, but unlike javascript LSL is a strongly typed language requiring all variables to be declared to be of a specific data type prior to using.

To embed LSL to an object, open the build tool, navigate to the contents tab and create a new script.

I have listed a couple simple LSL scripts below to demonstrate the language in action.

Hello, World example

Keeping with the tradition, the following example script will output Hello, World whenever someone touches it's corresponding object.

The llsay() function accepts two parameters, an integer channel and the text, channel 0 is public anyone within the transmitting radius will see the message in their chat area. Other private channels are often used to enable communication between objects. If you want to pass messages from one object to another you can send commands on a private channel where the other object is listening on. The llsay function will transmit messages to a 20m radius around the object.

On clicking the object "touch" the following message will be displayed in the chat area

Sending an Email
The llEmail() function accepts 3 string parameters, destination email address, email title and test message.

The email below was delivered within seconds of clicking the object, the email not only contains the message passed in as a parameter but also additional details about the object such as location.

This function is often used by in-world robots which are interfacing with external system (not on SL) reporting back in-world activities. 

Move object
The llsetpos() function will change the position of the object to that defined by the vector passed as a parameter.

On clicking the corresponding object the object will move 1 meter upwards.

Conclusion

LSL scripting is very similar to nowadays's languages so syntax wise there is no learning curve, the only thing that one would need is some understanding of functions available all of which are documented at lslwiki.net. 

Second Life - Constructing the World

One of the most innovative characteristic on SecondLife is that everything you see in-world has been created by the SecondLife population itself and not the parent company Linden Labs. They simply provide Sims (Simulations) which are actually dedicated server hosting a portion of the map and an array of tools to enable users to created all the content. Everything from house, furniture, vehicles, clothing and even the Avatar's own skin can be created through the SecondLife viewer.

This session was dedicated to the creation of useful objects which can be used for e.g. as furniture. We all teleported to an area called FERMI which is basically a sandbox where all users are allowed to create objects freely.

In SecondLife everything is made up of one or more prims (primitives), even the avatar itself is set of prims together to form a human structure, a prim is just a basic 3D shape such as cube, cone or cylinder. Prims can then be linked together to form more complex structure e.g. the chair below.

The following chair is made up of 4 cylinders (legs and back), and 2 cubes (seat and back), the less prims you use in your object the faster it loads, so if something can be constructed from a single prim do not split it up. e.g. in the image below I could have created the 4 legs as separate prims from the back, but instead I extended the hind legs to form a part of the back. Sims also have a limitation of a couple thousand prims they will allow in that area.

On completion of the structure, just select all objects and link the objects together using the build tool, from that point onward that object will be considered as one.

Any object may be fully customised, for.e.g in the image below I have changed the wood grain texture of the chair to a darker one. (this can all be done through the build tool) 

 All objects in SecondLife have a Sit Here option on right click, this will make your Avatar sit on whatever is selected.

The below image shows my avatar sitting on my newly created chair, luckily the chair's seat orientation was correct on the initial try, buy if the avatar would have sat down facing backwards or some other way all that would need to be done is to rotate the seat to face the correct way (all prims have a pointing direction).

Conclusion
Creating objects in SecondLife was more entertaining than I had initially expected, it only took me a couple of minutes to get to grips with the UI and completed the above structure in less than an hour, granted most of the time was spent on trying to control the camera to get it to show me what I wanted to see and not on the constructing itself. So far the best approach I've found is to roughly align the prims using the on-screen drag-drop functionality and then fine tune each prim's size and position using the parameters in the build tool.