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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.
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.
New-Tech Magazine Europe l 51