PowerVR GPU to Deliver Better VR Performance on Mobile

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Yesterday, during the Google I/O 2016 Keynote, the Internet giant gave a significant portion of the two-hour long show to Virtual Reality. Google has been no stranger to the emerging technology, introducing, and subsequently giving it away, Google Cardboard back at I/O 14. This year however, they introduced Daydream, their new VR platform that will hopefully make virtual reality on mobile a hell of a lot better. As with any project that involves some sort of hardware, Google is working with the likes of MediaTek as well as big name device manufacturers, it looks as though Imagination Technologies, the firm responsible for the PowerVR GPUs that are inside many popular smartphones is getting involved, too.

A blog post from Imagination Technologies detail some optimizations that can be made to existing PowerVR Rogue GPU platforms to improve the overall experience for the end users, and to the keen eye out there, this might be considered cheating a little. One thing that Google made clear on stage during the keynote is that latency has a big hand to play in motion sickness and other problems relating to VR. Latency, that being the time from someone moving their head to this movement being displayed in VR, needs to be below 20 ms for things to run smoothly, but this brings with it some problems. The way to get this latency down is to use a method called "asynchronous time warping" which sort of cheats around the problem by stalling running animations for a moment and slightly distorting the overall quality of 3D objects. This can be achieved thanks to the multithreaded nature of modern GPUs, and this sort of thing is included in the Daydream SDK.

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Another big deal for virtual reality experiences on mobile is of course resolution. Anyone that has used the above Gear VR from Samsung will know that while the image is fairly crisp, it can also come off as a little blocky, too. This is because a combination of barrel distortion (caused by the spherical lenses) and the squishing of so many textures results in a less than optimal image. Imagination Technologies have a workaround for both improving the perceived resolution of an experience as well as reducing barrel distortion. The trick for this is to simply reduce the resolution at the edges of the image piped to the VR headset, this allows for the pixels in the center of the image to appear less squashed and distorted and if done properly, shouldn't give users any cause to wonder what has changed. This workaround won't work for everything, but it's a good way to make the most out of VR without having to do too much.