A method for real-time rendering of water droplets taking into account interactive depth of field effects

Many researchers have been studying computer graphics simulations of natural phenomena. One important area in these studies is the animation of water droplets, whose applications include drive simula-tors. Because of the complexity of shape and motion, the animation of water droplets requires long calculation time. This paper proposes a method for real-time animations of water droplets running down on a glass plate, using graphics hardware. The proposed method takes into account depth of field effects, and makes it possible to change the focal point interactively depending on a point in the center of the scene being observed. 1. Introduction Recently, many computer graphics researchers have studied simulations of various natural phenomena such as clouds, water, terrain, and flame. Their research results have been used in entertainment applications such as computer games. Among those simulations, the animation of water droplets is indispensable for drive simulators, for rendering scenes viewed through a windowpane on a rainy day, and for computer games. For displaying the animation of water droplets, several methods have been presented [2][3][4][5]. These methods can generate realistic animation. However, because the motion of water droplets is complex and ray tracing is used for rendering, there is a problem of long calculation time. In making an animation, it is important to create an image as fast as possible, because we must generate a number of images. 1 2 In recent years, however, increased processing speed of graphics hardware have enabled traditionally time-consuming process to be performed much faster. This paper proposes a hardware-accelerated method for real-time animation of water droplets. Additionally, we introduce depth of field effects. These effects mimic that whereby an eye focused on an object sees the objects placed out of the field of focus as blurred. Our method makes it possible to change the focal point interactively depending on the point in the center of scene being observed. A method of animating the flow of small amounts of shallow water like water droplets was developed by Kass et al. [1]. This method enables the efficient display of animated rain falling on a concave surface. However, it is difficult to apply their method to the animation of water droplets, which is our purpose, because of the absence of interfacial dynamics. A method of animating the flow of water droplets was developed by Kaneda et al. [2][3][4][5]. In it, the interfacial dynamics are taken into account [2]. That is, …