parhelia pixelshaders?

[TdB]

With four programmable texture and five programmable pixel shader stages on each of its four pixel pipelines, Parhelia-512's 36-Stage Shader Array boasts the largest and most powerful pixel rendering pipeline to date. The massive shading power of the engine allows Parhelia-512 to render the most demanding next-generation content at high performance levels.

this looks(on paper) like some very advanced pixelshaders, but what can all these 36 stages be used for?
can it do more instructions on less passes, like for example run doom3 in a single pass, even though it is only version 1.3?
and will developers have to code specific shaderprograms to use the extra stages?

i don´t know much about shaders, but how does these shaders differs from other pixelshaders v1.3 in real usage? can they do something other pixelshaders can´t do, or just do it faster(because they are 4 of them or because they have more stages).
how does these shaders compare to the ati radeon8500 pixelshader v1.4?

[Jazzz]

I don't know nothing about Pixel shaders but i saw this reply by Humus over at Rage3d about ATIs pixel shader 1.4

It's much more flexible and capable, thus allowing much better effects. You have more instructions, more texture accesses, arbitrary dependent texture reads, wider range [-8,8] instead of [-1,1], etc

does anyone know why Matrox chose not to implemtent Pixel Shader 1.4? Im sure that something made for PS1.3 would work with PS1.4 so is it more complex putting 1.4 on

[CaineTanathos]

1.4 works different

1.3 has been chosen proberly because of compatibilty in games
all GF3 and GF4 and those Xabre (from sis) have 1.3

this the url for some extra explanation:

http://msdn.microsoft.com/library/default.asp?url=/library/en-us/dx8_vb/directx_vb/Graphics/Reference/Shader/Pixel/Architecture/BlockDiagramTextureAddress.asp

[TdB]

so with ps1.4 you can do a loopback in the pixelshader-program and use result from an earlier loop.
but how does the extra stages in the parhelia pixelshaders fit in to all of this?

can you do more instructions without the need for a loop?
is it basically an increased instruction-count they are talking about?

[CaineTanathos]

yep thats what happens with the GF3/4 they have only 2 stages
I think 5 are more than enough for most games (future games)

[TdB]

can you explain what "stage" mean?
they mention texture-stages in your link, but i couldn´t find an explanation.

[CaineTanathos]

I think they mean the pixel stages , but as you know a pixel shader applies a texture on pixel, an example is pixel per pixel bumpmapping

[TdB]

actually, i don´t really know alot about pixelshaders, only that it is a programmable part of the gpu, where you can run small procedures that changes the texels.

i don´t know what "stages" mean, can you explain that? I haven´t done any 3d-programming, allthough i do understand the basics.

i read through the whole pixelshader reference, but I couldn´t find any good explanation of the term "stages".

[CaineTanathos]

I think they are 5 operations or 5 five different effects on it I think
You don't know how to program in 3d

[TdB]

You don't know how to program in 3d

not really, I have decided to learn it though, and i started messing around with the directx sdk. but i haven´t looked into the shader stuff yet, because I only have a kyro2 at the moment.

but you can consider me as a curious newbie.
Im currently at the stage where getting a triangle drawn on the screen, is considered a great victory.

[Lemmin]

I have done 3D programming, but I haven't researched what the shader stages are, and my directX is several years out of date

I'm assuming, though, that each shader is like a pipeline in a CPU, and the 'pipeline' has 5 programmable sections which can each be programmed to do a certain pixel shading function. The first stage might apply a secondary texture, the second stage some filtering etc, and the pixel is 'passed' down the pipeline to the next stage every time the clock ticks... so it takes 5 cycles for a pixel to get through all 5 stages (but the next pixel is just behind in the pipeline).

Can someone who knows enlighten me?

LEM

[TdB]

that makes sense, I have heard that the four pixelshaders on parhelia can be daisy-chained into fewer but more complex pixelshaders, and thereby offering additional stages.

maybe it means you can trade the parallel nature of the 4 shaders for one single shader with 4 times the number of stages.

[CaineTanathos]

TDB, only 2 shaders can be connected, so a max of 10 stages per pass

[TdB]

so what do they mean by "36-stage shader array"?
is it just PR-spin?

[CaineTanathos]

sorry I did write something what I didn't meant
"You don't know how to program in 3d"
should be
you don't have to know how to program in 3d to understand the shaders , well the basic theory

Well the complete shader is a 36 shader array

it can do 4 pixels per clock with quad texturing and 5 pixel shader operations

so 4 textures + 5 pixelshader ops = 9
and it had 4 things of these so 4 * 9 = 36



so basically you do 4 textures on the object and then add a pixel shader on it

a pixel shader has a nicer effect