New-Tech Europe | November 2016 | Digital edition

Conclusions As we have seen throughout this article, multiview is a game changer for mobile VR as it allows us to unload our applications and finally consider the two similar views as one. Each draw call we save is a new opportunity for artists and content creators to add more life to the scenes and improve the overall VR experience. If you are using your custom engine and OpenGL ES 3.0 for your project, you can already start working with multiview on some ARM Mali based devices, like the Samsung S6 and S7. Multiview is also drawing increased attention from industry leaders. Oculus, starting from Mobile SDK 1.0.3, is now directly supporting multiview on Samsung Gear VR and if you are using a commercial engine such as Unreal, plans are in progress to support multiview inside the rendering pipeline.

getting bigger and bigger, our content becoming increasingly more complicated and our rendering time staying the same. We have already seen what we could save on the CPU side but sometimes fragment shaders are the real bottleneck. Foveated rendering is based on the physical properties of the human eye where only 1% of our eye (called the fovea), is mapped to 50% of our visual cortex. Foveated rendering uses this property to only render high resolution images in the center of your view, allowing us to render a low resolution version on the edges. For more information on foveated rendering and eye tracking applications, you can have a look at Freddi Jeffries’ blog Eye Heart VR. Stay tuned for a follow-up of this blog on foveated rendering theory.

We then need to render four versions of the same scene, two per eye, one high, one low resolution. Multiview makes this possible by sending only one draw call for all four views. Stereo Reflections Reflections are a key factor for achieving true immersion in VR, however, as for everything in VR it has to be in stereo. I won’t discuss the details of real time stereo reflections here, please see Roberto Lopez Mendez’s article Combined Reflections: Stereo Reflections in VR for that. In short, this method is based on the use of a secondary camera rendering a mirrored version of the scene. Multiview can help us achieve the stereo reflection at little more than the cost of a regular reflection, thus making real time reflections viable in mobile VR.

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