Introduction

On Monday, we gave a definition of VR as: the induction of targeted behavior in an organism by using artificial sensory stimulation, while the organism has little or no awareness of the interference.
We then looked at boundaries of the definition. For example, should reading a novel be considered VR?
We talked about how in a truly immersive VR system many of the neural structures used when an organism explores its in environment are activated in the VR setting.
We defined terms such as virtual environments, augmented reality, mixed reality, telepresence, teleoperation, and perceptual engineering.
We also looked at the amount of interactivity the system afforded between non-interactive, open-loop, and fully interactive, closed loop.
Today, we start by defining a few more concepts related to VR, talk about common VR experiences which might help you come up with project ideas, and then start laying the ground work to learn about Web VR.

Universal Simulation Principle

How "real" should a VR experience be?
One could try to make it faithfully and exactly match our physical world as far as the organism can tell.
The universal simulation principle is the hypothesis that: Any physical mechanism in the real world can be simulated in VR.
Since our brains are most familiar with the real world, this is often a goal that is strived for as witnessed by, for example, many first person shooter (FPS) style video games.
Even in the FPS case, we typically present a view of the world different from ordinary experience. As a VR creator one should be willing to experiment with different ways to extend reality, be it in cartoon-like, directions or whatever, to present a reality which in some ways can be better than reality.

Synthetic Versus Captured

Two extremes exist when build a VR world:
- We may program a synthetic world which is completely invented from geometric primitives and simulated physics.
- We can create an experience based on captured data from modern imaging devices.
Most video games use the synthetic approach and it was also used in early virtual environments.
To capture the physical world on typically needs to take panoramic images.
Often still, too much information is lost if we only rely on the scene projected onto the cameras.
For example, if the user changes their head position and viewpoint, we want to accurately capture this.
To handle this, we need to use or capture depth information using SLAM (simultaneous localization and mapping) techniques, often this involves using at least two cameras).
We also have to worry about uncanny valley effects. That is, systems with avatars for people or organisms in the scene which are close to real but not quite and which cause the person experiencing the environment to feel uneasy.

Health and Safety

VR has the power to overwhelm the senses and the brain, leading to fatigue or sickness.
This is often referred to as simulator sickness or VR sickness.
VR sickness can be caused by: latency of refreshing to new points of view (greater than 100ms tends to cause problems, want `<=20`ms), juddering and smearing from changing your point of view combined with field of view if the frame rate is too low, the screen door effect from being able to see between pixels, etc.
These are hardware problems, but VR sickness is more typically caused by the VR developer asking too much of the user.
In VR settings, the brain often works harder to integrate the unusual stimuli being presented, resulting in fatigue.
Inconsistencies with prior expectations and outputs from other senses can cause dizziness and nausea. (For example, me trying to play Temple Run in VR.)
Another cause for fatigue is interfaces which require large amounts of muscular effort. For example, require the using to keep the arms aloft in order to manipulate things in a scene.
This can lead to a problem known as gorilla arms which might be avoided by choosing a better interface design.

Modern VR Experiences

We are now spend a moment to look at some common kinds of experiences for which VR is used.
If you have a VR device already, I highly recommend trying to experiment with several of these.

Video Games

These can feel more realistic and can either have a first person point of view (from the characters eye like (a) and (d)) or third person point of view (from above or behind the character as in (c))

VR Cinema

VR Movies can be fully immersive as in Henry shown above where you can look in any direction in the scene.
Or they can show 2D or 3D movies from a movie theater-like environment within VR.
Arguably for 3D movies this is a much better setting than 3D TVs.

Telepresence

These let us feel what its like in a remote environment.
It is implemented often using 3D parnorama capture devices.
Events like concerts or sports matches can be attended in this way.

Virtual Societies

People from many different physical locations can easily get together in a VR meeting point.
This is like a supped up video chat.

Empathy

One can experience things that one cannot experience in the real world about other people.
The above is an image from a VR experience of a guy and a girl swapping bodies in VR. (They see out through each other's headsets).

Education

Using VR one can practice activities like flying a plane, in the safety of a VR setting before doing it in the real world.

Virtual Prototyping

In VR one can test out the designs of real world things cheaply before building them.

Health Care

Using VR doctors can visualize internal structures of patients.
VR also allows one to plan and try out operations virtually before one does them in the real world.
It also has teleoperation possibilities such as remote surgery.

Augmented and Mixed Reality

With VR and Augmented reality we can add to real world scenes virtual objects.
This might be used in games such as Pokemon Go above.
Or it might be used in applications such as museums etc where additional information and graphics is provided about objects.

New Human Experiences

Besides empathy building experiences, VR can allow for experiences that would be impossible otherwise.
Like fantastical roller coaster rides or virtual guillotines.

History of VR

Human simulations of reality date back to the first cave paintings in Europe 30,000 years ago.
Although there are ancient antecedents, the current forms of perspective painting date to the Renaissance in the 1400s.
Painters such as Vemeer (1632-1675) developed techniques similar to modern 3D projections using techniques such as camera obscura.
Starting with Muybridge in the 1870s one gets the first motion pictures.
Flight simulators to teach pilots to fly date to the Link Trainer from 1929.
One of the first popular stereoscopic project systems is View-Master (1939).
The first VR system is due to Ivan Sutherland 1968.
Jaron Lanier after leaving Atari, started VPL in 1984 one of the early commercial VR companies.
Virtual Boy 1995 was an early cheap VR system from Nintendo.
VFX1 by Forte Technologies came out in 1995 with a $695 system that connected i386 PCs that could play Quake, DOOM, etc. It had dual 263x230 LCD displays refreshing at 60 Hz.
Modern day VR Systems include: Oculus Rift and Go, HTC Vive, Google Cardboard, Samsung Gear VR.

HTML and Javascript

We are now going to start talking a little about HTML and Javascript.
We will use these to code WebVR virtual reality examples

HTML Variants

The most common variant of HTML today are:

ISO HTML (HTML 4.01) which is specified using SGML a
XHTML 1.0 Transitional
XHTML 1.0 STRICT
XHTML 1.1
HTML 5/XHTML 5

XHTML 2.0 was under development for several years, but was eventually abandoned.
HTML 5/XHTML 5 have been stable W3C recommendations since October 2014.
HTML 5.2 became a candidate W3C recommendation on Dec. 17, 2017.
The WHAT WG also maintains a "living standard version" of HTML which is updated almost daily.

Basic Syntax

The fundamental structural unit of HTML is a pair of tags.
For example, a paragraph might be specified with: <p>The quick brown fox..</p>
Here <p> is called the open tag and </p> is called the close tag. The quick brown fox is the content of the tag.
XHTML documents are case sensitive -- tags must be lower case for the document to validate. HTML documents can be case insensitive.
To be a legal XHTML document, every open tag must be closed. Further, the nesting must be legal.
In HTML 5, some tags do not need to be closed: area, base, br, col, command, embed, hr, img, input, keygen, link, meta, param, source, track, wbr .

Here are some examples:

<img src="my_picture.png" ></img> 
    <!-- this is okay in an XHTML document (not in HTML 5). 
    BTW, this is an example HTML comment -->
<img src="my_picture.png" /> 
    <!--this is okay for both XHTML and HTML 5 and 
is an abbreviation for the line above -->
<img src="my_picture.png" >  
  <!--okay only in HTML 5, but don't use for this class -->
<P>old style paragraph</P> 
   <!--okay only in HTML 5, but don't use for this class -->
<p><i>Hello</i></p> <!--okay -->
<p><i>Hello</p></i> <!--not okay -->

Open tags may have attributes. For example, src in the image tag above. The value of an attribute must be given in double quotes or single quotes for XHTML. Quotes are optional for HTML 5.

For this class, I want you to use XHTML syntax because it will work in the HTML case and gives your documents greater flexibility and makes it easier to find bugs.

Minimal HTML 5 Document

In HTML 5 a lot of the syntax which is hard for humans to remember has been stripped-away.

Notice the !DOCTYPE is much simple, and notice how we specify the character set:

<!DOCTYPE html>
<html>
    <head>
        <title>Simple HTML</title>
        <meta charset="utf-8" />
    </head>
    <body>
    <h1>Example HTML 5 document.</h1>
    <p>Example paragraph.</p>
    </body>
</html>

This basic structure will also work for XHTML 5 -- we just need to follow XML conventions for closing tags when we start to add content.

VR Experiences, History, Start HTML

Outline