Save 'Em is a 3D augmented reality game played with a head-mounted display and handheld "control wand". What is augmented reality, you ask? It's actually quite simple - augmented reality lies in the center of a continuum, with reality on one end and virtual reality on the other. It's a display technique which seeks to take both real elements and virtual elements and merge them into a single, unified image such that the virtual entities appear to have a real, physical presence. As always, a picture is worth a thousand words. If you're still confused, download the gameplay trailer on the right and I promise you'll immediately understand what augmented reality is all about.
Save 'Em was designed and implemented during the Summer of 2006 as part of a undergraduate research project with Dr. Ehud Sharlin at the University Calgary. Save 'Em was written in C++ and uses the freely-available ARToolkitPlus library to provide visual tracking.
Save 'Em's gameplay is simplicity incarnate. Your goal is to get the Dudes from their starting position to the exit while minimizing casualties. You have only one tool to accomplish this: a handheld control wand. When the player holds the wand above the playing area, nearby Dudes will run directly towards it. With this tool, the player can guide the Dudes to safety, much as one might entice a mule using a carrot on a stick.
I must admit, when I first started working on Save 'Em, I had my reservations about the project. At the time I knew nothing about augmented reality and I was unsure about its ability to carry a game. Luckily, I think the game managed to hit a real sweet spot which managed to balance simplicity of design with fun, engaging gameplay. The public reaction to Save 'Em has been great - most people have never even heard of augmented reality before, so being the person that introduces them to this new concept is a real treat. In fact, augmented reality is still such a niche concept that, as someone who has completed one augmented reality game and is now working on another, I think I have legitimate claim to being one of the world's foremost augmented reality game designers. How cool is that?
One of the coolest things about Save 'Em is something I don't show off in the video - it was a feature that just got added at the last moment. The visual tracking used in Save 'Em provides information not only about tracked objects (such as the game board) but about the position of the camera as well. We use this information in Save 'Em to measure the distance of the player from the board, allowing us to create 3D positional audio that seems to emanate from the virtual entities themselves. As the player moves his head towards the board, he'll begin to hear things which were previously inaudible: the roar of the fire and the moan of shambling zombies. As he pulls his head away, the sounds fade. Although it's a little effect, it significantly helps to perpetuate the idea that the Dudes and the world they live in are real entities, with a tangible physical presence.