Upcoming VR optimisations in UNITY 5.4 - What do you think?

Hi Jon

Currently when Unity performs a render from a VR enabled camera in Unity it will internally perform one set of culling and then in turn render the left eye and then the right eye. The optimizations we are working on internally at the moment move most of Unity over to performing only one rendering pass that will render to both eyes at the same time. This packs both eye targets into one double wide target and when it gets to Unity's render thread we will at the last possible moment double up the render call again binding appropriate matrices and setting up the viewport to render to the correct half of the double wide target for each eye.

If you look at your current VR project in the Unity profiler you should see that on the Main Thread each camera ("Camera.Render") that is enabled for VR will generate two sets of "Drawing" markers one for each eye. The second of those markers should go away with the optimizations enabled so reducing the VR "Drawing" time by 50%. We are also seeing a large reduction in the time spent on the GfxWorker Render Thread as a result of this optimizations as well.

Currently we are targeting Oculus Rift and PlayStation VR with this round of optimizations, we'll be looking into optimizations for GearVR a little further down the line.

Hope this is of some use.

Robin