Real-Time Animating and Rendering of Large Scale Grass Scenery on GPU

A method for animating and rendering large grass scenery in real-time is presented. The grass scenery consists of geometry-based grass blades and image-based quads covered with clumps of grass texture. Geometry-based grass blades are rendered for animating interactively for grass scenery close to camera. Imaged-based quads covered with clumps of grass texture are rendered for those far away from the camera. Seamless transition of the above two level of details (LOD) can be attained by special arrangement of grass density distribution and modulating the alpha channel of grass texture. The density of grass is defined with a density map to simulate natural grass distribution. GPU-based collision detect between virtual object and grass blades is used for interactive animating. Real-time animation of virtual objects striding in the grass scenery illustrates that the method can give people deep immersion and high fidelity for simulators and computer games.