Posts tagged occlusion culling
OpenGL vs DirectX: The War Is Far From Over
Oct 7th

The War Is Far From Over
I’ve chosen the title based on the popular article that tries to prove that OpenGL lost the war against Direct3D. To be honest, I didn’t really like the article at all. First, because it compared OpenGL 3 which targeted Shader Model 4.0 hardware and DirectX 11 which targeted Shader Model 5.0 hardware. Besides that, as we will see, the war is really far from over… This article aims to list the most important features introduced by OpenGL 3.x, OpenGL 4.x, Direct3D 10, Direct3D 11 and we will also talk about the promised features of the upcoming Direct3D 11.1 to be fair with DirectX
GPU based dynamic geometry LOD
Oct 25th
Dynamic geometry level-of-detail (LOD) algorithms are very popular and powerful algorithms that provide a great level of rendering performance optimization while preserving detail by using less detailed geometry for objects that are far away, too small or otherwise less significant in the quality of the final rendering. Many of these are used since the very beginning of computer graphics technologies and are present in some form in current CAD softwares, video games and other graphics applications. While determining the appropriate geometry LOD was previously the task of the CPU, with todays hardware it is possible to also offload this to the GPU which excels at handling large amount of objects in parallel.
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Hierarchical-Z map based occlusion culling
Oct 19th
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.
OpenGL 4.0 – Mountains demo released
Oct 11th
OpenGL 3.0 capable GPUs introduced a level of processing power and programming flexibility that isn’t comparable with any earlier generations. After that, OpenGL 4.0 and the hardware supporting it even further pushed the limits of what previously seemed to be impossible. Thanks to these features nowadays more and more possibilities are available for the graphics developers to implement GPU based scene management and culling algorithms. The Mountains demo showcases some of these rendering techniques that, as far as I know, were never implemented so far using OpenGL. In this article I will present the key features of the demo that will be discussed in more detail in subsequent articles. Demo binaries with full source code are also published.
