FLUID SIMULATION BY PARTICLE LEVEL SET METHOD WITH AN EFFICIENT DYNAMIC ARRAY IMPLEMENTATION ON GPU

We propose an efficient method to treat dynamic array data on Graphics Processing Unit (GPU), which is applica- ble to fluid simulations. Few numbers of dynamic structures have been realized on GPU since most of the previous meth- ods store the data in texture to represent the structure and it is difficult to manage the dynamic structure on the texture. Our method uses vertex buffer object for representing the data structure and combines the transform feedback and the geometry program, which are the functionalities of GPU. Our method offers a simple but an efficient way of realizing dynamic array on GPU. Furthermore we apply our method to the implementation of a particle level set method. The particles data are represented by our dynamic array and they are updated, added, and deleted completely on GPU. By using the method, a fast and accurate fluid simulation can be realized. different kind of fluids (e.g. water and air). The level set method (15) has been widely used as the surface tracking method for not only a fluid simulation but also many areas such as computer graphics, image processing and computa- tional geometry. The level set method represents the inter- faces as the zero value points of the implicit function called a level set function, and tracks the interfaces by updating the function based on the equation called advection equa- tion. But naive implementations of the level set method for a fluid simulation suffer from a volume loss caused by nu- merical dissipation. To alleviate the problem, the method is extended to the particle level set method (6), which is known as one of the most accurate surface tracking meth- ods. The particle level set method additionally places ficti- tious particles around the interfaces, and updates the parti- cles independently of the level set function. The method can track the interface very accurately by correcting the level set function with the information of the particles. The accuracy is however achieved at the expense of high computational costs. To address this problem, we show a fast method that accelerates the particle level set method by exploiting the parallel computational power of GPU. The particle level set method needs addition and deletion of particles in the simulation of fluid to accurately track the surfaces. Previ- ous GPU-based simulation methods store data as a form of textures. However, textures are not suitable for storing the particle's information since the number of particles dynam- ically changes throughout the simulation. We alternatively use vertex buffer object to store the particle data. By com- bining transform feedback and geometry program, that are the functions of GPU, we realize dynamic array on GPU. In other words, update, addition, and deletion of element are carried out fully on GPU. Our method offers a simple and efficient way of particle addition and deletion in the particle level set method. Finally we show a complete GPU imple- mentation of the fluid simulation with the free surfaces by using our method. Contributions of this paper are listed below.