Animating Prairies Simulation with Shell Method in Real-time

Real-time simulation of grassland, especially the dynamic grassland under the effect of external forces such as wind is an important research topic in photorealistic simulation of natural scenes. It is also a challenging problem due to the huge number of grass blades. In this paper we put forward a method to represent the large area of dynamic grass realistically in real-time. In the method, we implement the real-time grass representation by using shell strategy, and based on the strategy, we further realize the simulation of dynamic grassland in wind. In order to solve the over transparent problem in the silhouette area of layered textures representation, we use vertical slices strategy, with which the rendering effects are improved. The grass shift in wind is simulated by moving the multilayer vertices. The vertices movement is computed by vertex shader program in GPU to achieve high simulating speed. To improve the rendering effects, we utilize the fragment shader of GPU to compute the grass lighting model. The quadrilateral continuity issues is also considered in the generation of layered grass textures. Experimental results show that our method can simulate dynamic grassland realistically in real-time, making our method is valuable for the application in virtual reality and games.