Originally posted by Anux
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Mesa's CPU-Based Vulkan Driver Now Supports Ray-Tracing
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Originally posted by Anux View PostAs we can see in many benchmarks on phoronix AVX* is a perfect fit for ray tracing (a ray is a vector).
However, once you move up to 256-bit or 512-bit, you'd be much better of using a SIMD programming model. That's how GPUs work, after all!
Originally posted by Anux View PostBut even a 96 core CPU is much to slow for real time RT.
Graphics coming back to the CPU? Not necessarily in a CPGPU format either! The Inquirer caught a Ray Tracing demo from Intel, that used the 45nm
Six months later, they supposedly had optimized it to the point that a 1.2 GHz Ultra Mobile CPU (probably a 45 nm Core 2, I'd guess) could render 512x256 at 25-45 fps.
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Originally posted by Anux View Postyour funny or did you mean this serious? Following that "logic" we wouldn't even need a multi core CPU for ray tracing because ID Software already did it on the 286 in 1992. https://en.wikipedia.org/wiki/Wolfenstein_3D
Look how I pwnd you all!!11!!1!
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Originally posted by coder View PostNo, that would be wasteful.
However, once you move up to 256-bit or 512-bit, you'd be much better of using a SIMD programming model.
Intel famously demonstrated realtime ray-traced Quake at 768x768 ...
But yes if you want to make sacrifices modern real time RT is surely possible on the threadripper96c just reduce the resolution to 256x144 and it will run like a charm. 4k not so much.
Originally posted by coder View PostI'm not sure how serious you're being, but that's ray-casting.
It was purely 2D and nothing remotely like what we know as ray tracing... not even then.Last edited by Anux; 08 March 2024, 10:21 AM.
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Originally posted by Anux View PostWhat are you talking about? Have a look at any phoronix benchmark that compares AVX to non AVX with a raytracer, nearly 100% improvements in some cases.
Originally posted by Anux View PostYou seem to be confused, AVX as well as SSE is SIMD.
Originally posted by Anux View PostYes and the same argument is to be made as for ET: Quake Wars. It will run on any modern cpu but do you really think that looks anything like modern raytracing?
Originally posted by Anux View PostI was somewhat serious. Can you explain the difference between raycasting and raytracing?
They cast one ray per vertical column of the screen. If you played at 320x240 resolution, each frame was computed by casting only 320 rays.
Originally posted by Anux View PostYour Intel examples also are nothing remotely like what we know as ray tracing, that was my argument.
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Originally posted by coder View PostI didn't say not to use AVX, just not to waste an entire 256-bit operand on representing a single vector (or limit yourself to 128-bit).
If you don't know the difference between vector arithmetic and SIMD, then it sounds like you've got some reading to do.
With a 96-core CPU, I'd imagine you could afford to make some quality upgrades.
They cast one ray per vertical column of the screen. If you played at 320x240 resolution, each frame was computed by casting only 320 rays.
To be honest, I don't know anything about the technical underpinnings of Intel's demos
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Originally posted by Phoronos View PostAny cpu based graphics is a bad design from the start and should be avoided.
At work we archived old in-house software releases that didn't support more recent versions of the proprietary framework via flatpak.
People can install the old binaries as-needed and run the old Software. As the old software doesn't contain recent GPU drivers software rendering is used and it is plenty fast.
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Phoronix users try to make modern ray-tracing somehow viable on CPUs: https://www.youtube.com/watch?v=7haqnQvrYfI
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Originally posted by Anux View PostI don't know what you try to say here? But I guess it comes down to you not understanding what SIMD is and how you use it.
I'm currently using SIMD in my hobby raytracer and have already read all I need to know about it, Michaels benchmarks prove that I'm right and 10s on wikipedia would have spared you the disgrace: https://en.wikipedia.org/wiki/Single..._multiple_data
These ISA extensions support vector-oriented programming models, like horizontal sums, dot products, shuffles, etc. They also support SIMD programming, in which the vector register components are treated as scalar registers of independent sets of program state.
There's a reason Nvidia calls each SIMD lane a "thread". That's because their programming model is pure SIMD. If you want good scaling from AVX or AVX-512, it's generally better if you can follow a pure SIMD approach.
Originally posted by Anux View PostExactly, do you get my argument now?
Originally posted by Anux View PostThat's obvious. You could have watched the video I linked earlier or carefully read what I wrote about it ...Last edited by coder; 08 March 2024, 07:03 PM.
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Originally posted by TemplarGR View Post
The "dedicated ray tracing hardware" are really just programmable shaders mostly.... There is no "fixed function" ray tracing hardware. It is not some kind of "special instructions only RT uses".
For the rest I agree with you.
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