Special effects and virtual reality

This last chapter presents a selection of special topics as well as basic techniques that are required for virtual reality applications. Virtual reality comprises more than just displaying a scene or a sequence of scenes on a computer screen. Stereoscopic viewing which is necessary for real 3D effects belongs to virtual reality. In addition to seeing a virtual world, virtual reality can also involve sound. Even tactile information might be incorporated with wire gloves. An important feature of virtual reality applications is also that the user can move around in the virtual world and interact with the virtual world. Moving through the virtual world means here that the person is moving, not just controlling the navigation through the scene by mouse commands. For this purpose, sensors to locate the position of the viewer are required. Interaction means that objects in the scene can be manipulated, for example shifted to other positions in the scene. Even if the necessary technical equipment for virtual reality applications is not available for most computer users, the principles of virtual reality can also be understood when a normal computer screen is used. From the computer graphics point of view, moving around in a virtual world is nothing else than a viewer who navigates through the scene, i.e., by changing the position of the viewer which is nothing else than translating the centre of projection. This topic was treated in detail in section 5.8 and all example programs allow a navigation through the scene. Of course, the mouse must be used for navigation in these programs. But the computations for the projections are identical as long as reliable data are available about the position of a viewer in a virtual world.