Single Pass Stereo: a study

This is a series of two posts explaining Single Pass Stereo and discussing it’s uses and problems. In addition to providing an explanation of Single Pass Stereo, I also want to raise awareness of it’s problems and call on the developers to prevent them from spreading to many more XR applications.

  1. Single Pass Stereo: is it worth it?
  2. Single Pass Stereo: wrong depth cues, discomfort and potential risks

Single Pass Stereo (SPS) is technology introduced by NVIDIA and graphics cards from GTX1060 onward support it. It is used to simultaneously project the geometry for the left and right eyes in order to reduce the processing time of each frame. It states that the developers can almost double the geometric complexity of their world without having an increase in processing times. This sounds like a great technology and is already integrated in Unreal Engine and Unity.

In the introduction above, there are two key phrases that I have highlighted and are a source of misunderstanding or frustration for the developers. Having implemented it, I was surprised by the lack of information I could find about it and I decided to check it more. After extensive use for months, I realized that SPS is also bringing problems to the table, instead of only helping with the processing times.

The first post is “Single Pass Stereo: is it worth it?” and discusses SPS at a high level, about it’s advantages and disadvantages, how one can determine if they will benefit from using it and alternatives.

The second post is “Single Pass Stereo: wrong depth cues, discomfort and potential risks” and presents the problems of SPS, proof of their existence using Valve’s OpenVR sample code as ground truth and potential solutions.

Thank you and stay safe!