OpenGL Headline News
Oct 21, 2010
Hierarchical-Z is a well known and standard feature of modern GPUs that allows them to speed up depth testing by rejecting large group of incoming fragments using a reduced and compressed version of the depth buffer that resides in on-chip memory. The technique presented in this article uses the same basic idea to allow batched occlusion culling for large amount of individual objects using a geometry shader without the need of any CPU intervention that is unavoidable using traditional occlusion queries. The article also provides a reference implementation in the form of the OpenGL 4.0 Mountains demo that uses the technique for culling thousands of object instances.