Hardware Accelerated Rendering Of Virtual Environment

Virtual environment is an important part of virtual reality system and there are many people who concentrate on this area. Because realistic and natural interface communicating with computers is provided, it is widely used in many regions, such as: CAD, Digital Entertainment, Computer Art etc. Usually there are two parts of these applications: rendering of virtual environment and interaction in system. Objects in the system are realistically presented through virtual environment rendering. Virtual environment is more complicated then before and the quality of rendering also is higher. There is a great achievement about both ability and function of graphics processor unit (GPU). While GPU can process more and more calculation through hardware, it becomes programmable.In this paper, starting from a brief introduction to the development of graphics hardware and shading languages, a detail introduction and analysis will be given to the technique of accelerated real-time rendering. These are basis of this paper. It will improve the performance of rendering by using programmable ability of GPU. Finally, discuss is given about the method of programmable ability of GPU and an actual implement of a virtual environment of seafloor is presented. Main program running on CPU maintains data structure and states while most actual rendering accelerated by GPU. There are four parts in virtual seafloor. The first part is real-time calculation of light that is evaluated per pixel. Blinn-Phong lighting model and a model about sun's rays are used. Better rendering results are achieved. The second is multiple kinds of fog. One of them is layered fog that considers the effect of depth. The other is animated fog. With the help of periodic functions, it is easy to add a kind of animation that can simulate the influence of current to the fog. The third is simulation of simple plants' swaying with the current. The last is a particle system that simulates a series of air bubbles witch continually gush from sea floor.