遮擋剔除（Occlusion Culling）與視錐體剔除（Frustum Culling）是否可以同時起作用？（）
可以的
Occlusion Culling is a feature that disables rendering of objects when they
are not currently seen by the camera because they are obscured by other objects. This does not happen automatically in 3D computer graphics since most of the time objects farthest away from the camera are drawn first and closer objects are drawn over the top
of them (this is called "overdraw"). Occlusion Culling is different from Frustum Culling. Frustum Culling only disables the renderers for objects that are outside the camera's viewing area but does not disable anything hidden from view by overdraw. Note that
when you use Occlusion Culling you will still benefit from Frustum Culling.
遮擋剔除， 當一個物體被其他物體遮擋住而不在攝像機的可視範圍內時不對其進行渲染。.遮擋剔除在3D圖形計算中並不是自動進行的。因為在絕大多數情況下離 camera 最遠的物體首先被渲染，靠近攝像機的物體後渲染並覆蓋先前渲染的物體(這被稱為重複渲染"overdraw"). 遮擋剔除不同於視錐體剔除. 視錐體剔除只是不渲染攝像機視角範圍外的物體而對於被其他物體遮擋但依然在視角範圍內的物體，則不會被剔除. 注意當你使用遮擋剔除時你依然受益於視錐體剔除（Frustum Culling）.
原文連結：http://blog.csdn.net/pizi0475/article/details/12883401