Imagination Technologies unveals ray tracing chip

[Kojack]

The PowerVR Wizard GR6500 gpu is a combination of the PowerVR Series6XT Rogue gpu with an RTU (Ray Tracing Unit) and scene management hardware.

The GR6500 is currently able to cast 7-10 rays per pixel on a 720p screen at 30Hz or 3-5 rays per pixel at 1080p and 30Hz.

Apparently Unity 5 (also just announced) will include a software simulation of the GR6500's ray traced lighting, with full support later.

I've been a raytracing fan for many years (since I first saw Real3D on the Amiga 24 years ago) and I eagerly await the day we can use such techniques in games. But sadly this news is useless to me. The GR6500 is a mobile SOC, so won't appear on PC.

Ray tracing would be particularly useful for Oculus Rift games. Due to the lens distortion algorithm, Oculus Rift games need to be rendered at around 1.7 times the panel size. On the standard 1280x800 dev kit, you need to render at around 2176x1360. Otherwise the centre pixels are low res. But with a ray tracer, the distortion algorithm can be performed earlier in the pipeline (when casting initial rays instead of as a post processing effect) and no extra pixels are needed.

http://techreport.com/news/26178/powerv ... e-graphics

[Zonder]

Hopefully AMD/Nvidia will do something as well now I suspect Nvidia will due to there work in this area already.

[Kojack]

Intel has pushed for ray tracing pretty hard, but Knights Landing costs a fortune (I don't think it's out yet, but the previous higher end Xeon Phi boards were $4000+) and needs a Xeon system. Just not cost effective.

[Zonder]

Isn't that due next year? Thats super computer market though I was thinking desktops

[Kojack]

That's why I said it costs a fortune.

But Knight's Landing is a sequel to a sequel to Larabee, which was designed by and for game programmers.

I'd love to code for a Knights Landing style system. 72 cores (Intel Atoms) with 4 threads per core, complete enough to run operating systems. GPU coding is annoying (no stack, no recursion, all the issues with shader units in a warp running different control paths, etc). I wonder how fast I can compile Ogre with one?

[Klaim]

Yeah also if I remember correctly, the communication about Knight's Landing by Intel was that it was the first step to get the same kind of hardware in desktop and everywhere. I really hope I can reach a day I don't have to switch languages all the time to get some nice graphics.

[Kojack]

You can do that now, just not at good framerates.

I wonder if anyone will ever make a voxel processing unit?

Physics processing units didn't really catch on after the PhysX flopped.
There was an AI processing unit (it had hardware accelerated raycasting and path finding).

If a raytracing unit is generic enough, it would have a ton of uses (physics, audio, etc). I don't know how much control over the raytracing operation in the GR6500 the user has though. Is there an equivalent of a shader language for the rays? A vertex shader to position stuff then a recursive ray shader to render?

I'm getting an urge to write another ray tracer.
(I once wrote one during a slow tutorial class. No students asked me for help (it was another teacher's class, I was just supervising the room), so I wrote a ray tracer and generated an animation with it. Only took a couple of hours)

[Zonder]

Just spotted this on there site didn't know it existed. Interesting it's has ties to OpenGL. Of course it works with the PowerVR RayTracing chip

http://www.imgtec.com/powervr/powervr_openrl_sdk.asp

Question is when will this hardware start appearing

[madmarx]

"the distortion algorithm can be performed earlier in the pipeline (when casting initial rays instead of as a post processing effect) "

I suppose that with dedicated tesselation shader + vertex_shader it could be possible to already draw already deformed meshes. Then some work would be needed too for the pixel shader to use the 'not distorded' position for the various lighting calculations. This should avoid post processing step and save quite a lot of calculations. Am I wrong?

Also, for realtime raytracing, I will wait too see it.

[Kojack]

The problem with tessellation plus curvature deformed meshes is that edges will no longer line up correctly, unless you tessellate down to the pixel level. Vertices would be moved correctly by the curvature, but edges between vertices are still straight. So anywhere that normally had a vertex adjacent to an edge will get a gap or overlap.

[Klaim]

Talking about ray tracing, there is a very recent article about that on gamasutra: http://gamasutra.com/blogs/AlexandruVoi ... _games.php

[Zonder]

Here is another interesting development (again I missed until now). A new type of massively parallel processor best reading the articles I am trying to get my head round how you would use it

Interesting bit in the register article

"In tests, a cluster of 48 of the processors on a PCIe board comfortably beat a 48-chip cluster of Intel Xeon 5650s when trying to complete a tough 'Planted Motif Search' problem."

http://www.theregister.co.uk/2013/11/19 ... or_launch/
http://www.micron.com/about/innovations ... processing