Most values of the depth will be concentrated in near-zero region, that is why we need the help of exponential part of FP to prevent the loss of precision for near-zero values. Therefore, the depth value (assuming default direct mapping of depth values) is calculated as follows:Īs a result, all pixels behind the clipping plane have their depth values laying outside region, so those are culled for the fragments sitting on the clipping plane the depth is 1.0, for all further fragments the depth approaches positive zero.Īs depth is reversed (the further the fragment the smaller the depth) we must set glDepthFunc(GL_GREATER) to make the depth test working properly.Īnd the final part, which brings sense to all that: we must use the floating-point z-buffer.

ZNear: distance to the near clipping plane (tiny constant, like 0.0000.1). I am confused… Somewhy I was sure it is, but now… Hm… Maybe I just confused myself…Ĭonfigure the projection matrix like this: It is important that the range is not -Wc<=Zc<=Wc for the approach described below. Using glClipControl(GL_LOWER_LEFT,GL_ZERO_TO_ONE) we set the clipping volume to be: Here is my plan that involves this extension: May I ask why you are so excited with ARB_clip_control? This extension could slightly improve precision, but I can still live quite good without it.I see this extension as part of the solution of the depth-fighting problem. If you write application for wider audience, well … many years could pass until many of them could try your application. If it runs on other people computers and you can control how they manage drivers, have NV cards, presumably post-Fermi, etc., you should wait at least a year to have a proper functioning. If it runs on your computer it is just fine. At least on your own computer.īut don’t force others to use them, since they can be unstable or miss some functionality.Īlso, it is not useless to write an application based on new features.

For other vendors the time could pass until the support is brought to users. But usually it requires some time for thorough testing and implementation polishing, inducing certain latency for the inclusion in the release version of the drivers. It is really great for enthusiasts wanting to try new features. NVIDIA releases beta drivers with the latest OpenGL at the same time a new specification is announced.

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