视野驱动的自适应阴影图

Adaptive shadow maps driven by visual field

阴影图是当前实时阴影绘制中的一种经典算法。该算法基于图像空间,当有限分辨率的阴影图映射到较大场景中时,就会由于采样不足造成锯齿形变走样。提出了一种实时的反走样阴影图算法,该算法首先获取当前视点所能够看到的场景范围,然后绘制该范围内的阴影图,并映射到场景中生成实时阴影。该方法同经典的阴影图算法相比,避免了场景中不必要的阴影绘制,提高了阴影图的利用率,反走样的效果很好。而且,该方法只需要绘制一到两幅阴影图,算法的实时性很强,可以满足一个上百万面片的大规模场景中实时阴影绘制的需要。

Shadow mapping is a classical algorithm for real-time shadow rendering.This algorithm is image based.When a shad- ow map with limited resolution maps onto a large virtual scene, it will suffer from the aliasing errors due to its insufficient sample.This paper presents a real-time anti-aliasing shadow mapping algorithm.Firstly, people get the area of the scene what they can see.Then this area＇s shadow map is rendered, and it is mapped back onto the scene to generate real-time shadow.Compared with standard shadow map algorithm, this method lessens the useless shadow rendering and increases the usage rate of shadow map. So the anti-aliasing shadow＇s point can be carried.Furthermore, rendering a virtual scene with shadow, only one or two shadow maps are required.It meets the real-time rendering of large scale virtual environment with millions faces＇ requirement.