Hardware instancing for real-time realistic forest rendering

Real-time rendering of vegetation is important in many applications, such as video games, internet graphics applications, landscape design and visualization. However, the visualization of large-scale forests has always been a challenge not only due to the high geometric complexity but also due to the small batch problem. Moreover, generating real-time shadows for forests will heavily increase the burden. The batch problem is caused by a large number of graphics API draw calls launched in every frame. Normally, rendering a tree model requires at least one graphics API draw call. As a forest usually consists of thousands of trees and the graphics API invocation is a relatively high cost for CPU, the large-scale forest rendering is often CPU bound.