Image Based Real-Time and Realistic Forest Rendering and Forest Growth Simulation

Real-time and realistic rendering of forest is an important and a difficult work in computer graphics and digital forestry. An image based real-time and realistic forest rendering software is developed in this paper. Three orthogonal billboards are used to represent the geometry and material of a tree, so that the 3D perception is enhanced and weak parallax of usual images based approaches is avoided. Shadows of all trees on the plat ground are generated through the stencil buffer, shadow projection and a mixture of the shadow with grass texture. Different billboards are chosen on the viewing direction and the lighting direction, so that the effect of object torsion due to poor image direction is avoided. Forest growth, forest rendering in different lighting conditions, navigation inside a forest, and flying over a forest are all simulated.