Brunelleschi's Experiment

In 1425 Filippo Brunelleschi invented game engines.

What he had invented, of course, was much more fundamental, much more revolutionary: linear perspective.  Game engines, and along with them the invention of virtual reality and augmented reality, were mere by-products of his work and as such they went without comment.

According to his adoring biographer, Antonio Manetti, here's how it happened...

One day in Florence in 1425 Brunelleschi assembled the good folk of the city in the Cathedral square.  He seems to have had something of the reputation of a wizard and the gathered audience must have been pleasantly mystified with what they saw.  Manetti doesn't give the exact details, but somewhere in the square before them were two objects, possibly placed on stands or easels, and probably concealed under cloths.  Brunelleschi asked for a volunteer.  A man was put forward and Brunelleschi accordingly asked him to stand behind the nearest veiled object which was then unveiled.  It was underwhelming.  It was a small rectangular panel, perhaps a painting, but, as it was facing away from the audience, it was difficult to tell what of.  Brunelleschi asked the volunteer to go close to the panel where he would find a small hole drilled in it.  He was to look through this hole into the square.  All the gentleman would have seen was the veiled object as it stood directly in the line of his sight, limited by the hole through which he was peering.

Brunelleschi gazes at the Duomo

(Photo: Jason Pier - used with permission

from Flickr: here)

Then the second object was unveiled.

Brunelleschi asked the volunteer what he saw.

'Sir,' he said, 'I see the Baptistry.'

The audience gasped in astonishment.

What the man was looking at was a mirror.  But what he was looking through was a painting of the Baptistery.  To him, when the mirror was unveiled it was as if Brunelleschi had simply plucked the veil from where it had hung in thin air opening up his view of the actual Baptistery in the square beyond.  What he was actually seeing was a reflection of Brunelleschi's painting of the Baptistery which matched the man's perspective exactly.  This matching of perspective made it real from the observer's limited point-of-view.

As underwhelming as this may sound to us, what the man saw would do nothing less than revolutionise the very way people in the West saw their world.

Previously, people were accustomed to depictions of the world around them which were stylised in terms of their visual perspective.  It is likely that this mis-match with visual reality was not much of a cause for discussion of disappointment.  Most of the time it must have gone without notice.  It was convention, and as such, was invisible in the same way the the page or screen upon which text is written is invisible to the reader.  However, once Brunelleschi demonstrated his grasp of linear perspective all other representational art must have become ... different for the good people of Florence.  It must have become different in the way the design of the iPhone3GS became ... different ... when the iPhone4 was unveiled.  The world was changed and people did not look at what was familiar which quite such familiar eyes.

Within a generation most visual art in Italy would take into account linear perspective.  Within a century this would rule art across Europe (even in England!).  The world - or the way people expected to see it - had been changed forever.

Now, about the invention of game engines, virtual reality and augmented reality.  Brunelleschi provided a model for those in that he had created a system whereby the viewer was immersed in a representation of reality rather than the reality itself.  The effect only worked because it provided a convincing experience - which is at the heart of video games and their engines today.  The foundation for virtual reality was also laid because the rules of linear perspective eventually lead to the transform matrix which allows 2d vector graphics to mimic 3d perspective in realtime on display screens.  And finally, Brunelleschi's experiment overlaid his version of reality - a possible reality - atop his observer's view of reality itself.  It the 'magic window' effect of overlaying digital content on a mobile phone's camera stream.

It has taken a while for technology to catch up with the vision presented almost six centuries ago and there is still some controversy over what Brunelleschi actually did in that square on that day, how he did it, and what he actually meant by it.

However, to close this little circle of ideas, you will find below a demo of one way in which Brunelleschi may have set up his demonstration.  It runs in a game engine and it is entirely dependent on your experience and your own point-of-view.

How will our growing expectations about the dynamic nature of imagery produced today shape the way we see our world tomorrow?


Click the image to begin.  W,A,S,D to move, I to move mirror up, K to move mirror down, T to switch sketches

Explore the piazza (there is no dome on the Duomo because it didn't exist in 1425).  Find the panel with the drawing of the Baptistery then go round back and peer through the peephole.  Raise the mirror in front slowly to see the drawing overlaid on the 'reality' of the 'actual' Baptistery in front of you.  You can toggle between the kind of pseudo-perspective common at the time and linear perspective, just to appreciate the impact of this visual change.