Game Development Reference
In-Depth Information
to theories, experiments, and debate. Early concepts about the nature of reality and virtual reality may have
started with Plato (approximately 424-348 BC) and Aristotle (384-322 BC). In his “Allegory of the Cave,”
Plato constructs a model for reality and how it is perceived [3]. Within the allegorical environment of a dark,
deep cave, he describes four kinds of individuals: prisoners, puppeteers, the released prisoners, and observ-
ers, all experiencing a different reality. The prisoners are chained to a bench and forced to watch a shadow
play performed by the puppeteers, carrying shapes and objects back and forth in front of torchlights. The
prisoners think that the moving shadows they see and hear are reality. The third group, the released prisoners,
has been unchained from the bench and, as they make their way out of the cave and into the sunlight, they
are beginning the process of acknowledging that the shadows on the cave wall are not reality. The observers
are standing outside the cave and learning about the sun and how it lights the world.
Plato disagreed with Aristotle regarding how humans perceived reality; he believed that the true “Forms”
of natural things or concepts were imperfectly understood by humans, whereas, Aristotle believed that
systematic observation and analysis could lead to the human understanding of the “Forms” of natural things
or concepts. [4]. Plato's belief that our experience was only a shadow of the real and unknowable “Forms,”
represents an interesting philosophical juxtaposition to the virtual reality we create today. In today's world,
we have another kind of CAVE (cave automatic virtual environment) for virtual reality. Invented in 1992, this
CAVE is a virtual reality environment made from projected images on walls surrounding a person wearing
a head-mounted display (HMD); it is not a holodeck yet, but it is approaching it.
Almost 400 years after Aristotle, Pliny the Elder wrote about the origin of painting, sculpture, illusion,
and human perception in his topic,
Natural History,
circa AD 77-79. You can almost imagine Pliny, relaxing
on the patio of his villa in Pompeii, telling the story of how Butades of Corinth, seeing a line drawing his
daughter had traced on the wall from her lover's shadow, illed it in with clay and ired the relief to make the
world's irst portrait [5]. Maybe later in the evening, Pliny would tell of the painting contest between Zeuxis
and Parrhasius, two great painters of the ifth century BC. Smiling at the memory, Pliny tells you of how
Zeuxis created a still life containing a bunch of grapes painted so realistically that the birds lew down from
a nearby tree to eat them. Seeing that, Parrhasius invited Zeuxis to remove the curtain from his painting to
reveal the image. When Zeuxis tried to do that, he discovered that the painting of the curtain was so realistic,
that he was fooled into thinking it could be drawn aside. Pliny concludes with the account of Zeuxis ceding
victory to Parrhasius, saying: “I have deceived the birds, but Parrhasius has deceived Zeuxis” [6]. As Pliny
undoubtedly noted, the creation of realistic images fascinates us, and each successive development in the
visual arts has been inluenced by that fascination.
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In the centuries from AD 1000 to 1700, great painters and sculptors discovered more ways to make illu-
sions. Trompe l'oeil was invented, and images that could create 3D spaces in our mind's eye illed churches
and mansions. The tools to create those illusions involved the scientiic analysis of perception and optics
by Alhazen Ibn al-Haytham (965-1039), the observations of Leonardo Da Vinci (1452-1519) and others.
In 1580, Giambattista della Porta perfected the camera obscura and another device that eventually became
known as Pepper's ghost [7]. Pepper's ghost is named after John Henry Pepper, who popularized it in 1862
from a device developed by Henry Dircks. This ancient device inds everyday use in the television studio as
a teleprompter and occasionally makes an appearance in a stage show or fashion video when they want to
include the animated image of someone in the performance space.
