AR BROWSER BASICS
While I said in Chapter 1 that you need a camera and a screen to experience AR, it may surprise you to know that the minimum requirement for an AR browser is simply a smartphone that has a GPS. Why no camera? Well, it is less common, but some developers have taken the approach of building applications that provide an AR experience through augmenting your hearing rather than using a visual method. Toozla is an application from a Russian company that detects the users’ location via GPS. When users come into range of a POI, an audio fi le begins to play, giving users an overview of their current surroundings. If users remain at the POI to listen, the application provides more detailed commentary. Like most AR applications, Toozla uses the Wikipedia API to provide some of its content, but Toozla also uses professionally recorded material to give users a richer tour guide experience. We are not going to cover building content for Toozla, but they do have an API if you are interested in producing audio content. You will fi nd them at www.toozla.com AR browsers work by using GPS to detect the user’s current location while the compass detects the direction the device is facing. With the user’s current location and their direction known, the nearby POIs can be displayed in the camera window. As the user moves the mobile device around, the accelerometer detects the elevation while the compass continues to detects the direction the user is currently facing. This combination enables the application to use the map data to build the AR view. In Figure 3-1, you can see POIs from the Qype world for the Wikitude browser shown on a map, with the map indicating their actual location. In Figure 3-2 the same POIs are drawn in the AR browser window, providing a visual indication on their locations.