Nicolas Boulay wrote:
Somebody post here about the design of raytring engine using very few
hardware to do it. So raytracing could be done with very few gates.
Fewer than with a generic cpu 'tile'. There is other solution. Because
of the fact that pipelining the 3D rendering is easy, you could put
the raytracing with the video DAC.
OpenRT is supposed to be much simplified and their site mentioned a chip
that does their algorithm in hardware.
How do you compute the cross product of two 256 x 1 vectors on a video
card? How many instructions does it take? -- more than one?
Depend on the hardware, on an asic you could put what ever you want.
My point is that with a FPS array processor that it is basically one
instruction.
If you know what Floating Point Systems used to make, you would not use
the term array processor to refer to a video card. Hardware has changed
over the years and array processor has taken on a slightly different
meaning, a system with a lot of processors now does the same job that
FPS's hardware did and it is now called an array processor although the
correct term is NUMA. Now, ClearSpeed is making a new type of array
processor that will do the same job.
Did you visit the ClearSpeed site?
You might say that a shader is a vector processor. Yes, it is (perhaps
it is better to call it a superscaler processor), but an OpenGL shader
works with vectors with a maximum size of 4. As I said, this hardware
is some help with ray tracing, but that doesn't make it an array
processor with the meaning applied to FPS's hardware.
That's just a virtual instruction langage. Each driver recompile it to
it's own asm. Nvidia very new chip use only scalar processor, because
most of the shader code are scalar not vectorise.
Interesting information. Since an array processor must be super scalar
in one way or another, a video chip that is scalar is not an array
processor.
--
JRT
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