LOVE Xmas 2012: Online Interactive Projection Mapping

This Christmas at LOVE we decided to take our 2D mural projection mapping a step further. LOVE commissioned an Ian Stevenson to come up with a new Christmas themed mural to cover our 5×3 metre wall by reception. My job was to develop a system that could enable us to projection map animations back onto the wall, and let people create, send and playback personalised greetings onto the wall via a live webcam stream. This was pretty tricky!

Here’s some more about it…

Projector
There were several show stoppers I had to overcome at the start. Firstly, where do I find a projector with a short enough throw; can cover a 5×3 metre wall; will stay on 24/7 without overheating; and will be bright and crisp enough to animate, light up and show personalised messages on the wall – bearing in mind users would also need to view these online, day and night (we have clients in China remember!). This took many phone calls, and professionals saying it couldn’t be done for under 4 grand. Well, we proved them wrong 😉 We were projecting on top of a print, so we only needed it bright enough to light up what was already on the wall. I found a pretty descent one for the job in the end. I’m rather knowledgeable with portable projectors now!

Webcam & Live Stream
Another potential show stopper was the webcam. We were running OSX, and the only compatible cameras were Logitec, so we bought the best one only to find that the drivers weren’t fully compatible with Mac’s. We had to have control over auto-whitebalance and auto-focus, otherwise the camera wouldn’t focus on the projection. So we ended up installing windows 7 on bootcamp, to gain complete control. Job’s a good-en. These were the two main issues, plus we had to stream at a high enough bit-rate that the text would be legible after encoding for the live stream.

Software
I developed the openFrameworks application on top of the previous quad warp projection mapping tool we developed, and added functionality for fading between several videos; connecting to the node.js backend; queuing messages (prioritising clients over users); and elegantly displaying messages on the projection. Nice text in openFrameworks was a bit of a nightmare to begin with. I had to build my own text-align and word wrapping functionality in.

The node.js backend handles all of the message creation and hosts the html/js. I hash the messages so they are gibberish in the query string when someone is sent a link, otherwise it’ll spoil the fun if they’ve seen the message already!

We are using a Flash front-end which uses external interface calls and callbacks to trigger and recieve events from Socket.IO