pipeline architecture

[Dio]

Blame our crappy terminology. 'Quads' in this context are 'Quad-pixels' not 'Quadrilaterals'. I'm not a big fan of it either, but we're stuck with it

 

[Dave Baumann]

snap

 

[demalion]

A search on the term "proxel" (the smiley in that post is a link, BTW) will drop you into the middle of some long discussions of this that go into a lot of detail from the different perspective of trying to understand and describe some architectures when this complexity was being exhibited. That term is one I made up (and no one else uses, so don't learn it ) to try to discuss pixel shading with some relation to the more easily understood pixel and texel terms, and the discussions touch on the topic question from many angles.

If you find the discussions confusing instead of revealing, just disregard.

 

[Rookie]

It's a shadow acceleration mode. If doing shadow buffers, it allows you to fill the buffer at up to 2x the fillrate. If doing stencil shadow volumes, it allows you to write stencils at up to 2x the fillrate.

Is it the only benefit of 32x0 pipeline?

BTW,How many textures are used in popular game? As I know,quake use 3 texture in some place,serios sam use tri textures,how about UT2004 or Farcry,painkiller?Does quadtexture is widely used now?

 

[KimB]

The number of textures used will vary from surface to surface, and will vary widely depending upon the game.

For a complex surface, I would suspect 4 textures would be a minimum.

Anyway, the hypothetical "32x0" that we're talking about here would have nothing to do with textures, but rather with rendering z and stencil data. Such an architecture would accelerate an initial z-pass (something that is necessary for shadow volumes, but is also helpful in allowing hardware to not have to render anything that will later be covered up), as well as stencil shadow volume rendering.

It may also be possible for such an architecture to accelerate other shadowing techniques, but that would depend upon the hardware implementation.

 

[Dio]

Z-passes are pretty pointless though unless you are doing stencil shadow rendering. Sort the data reasonably well front to back and you almost always get better performance than you do with a Z-pass.

I'm mightily sick of seeing applications that draw the sky first.

 

[KimB]

Z-passes are pretty pointless though unless you are doing stencil shadow rendering. Sort the data reasonably well front to back and you almost always get better performance than you do with a Z-pass.

As shaders get longer, this may no longer be the case.

 

[Dio]

As pixel shaders get longer it may not be the case. Who's to say geometry calculation won't need a humongous vertex shader?

 

[Simon F]

That may also depend on whether it is the "geometry" or "lighting" part that is taking up the majority of the VS instructions <shrug>

 

[Xmas]

As pixel shaders get longer it may not be the case. Who's to say geometry calculation won't need a humongous vertex shader?

Then perhaps it might be a good idea to be able to store VS output?

That may also depend on whether it is the "geometry" or "lighting" part that is taking up the majority of the VS instructions <shrug>

Nice to hear that, Simon... deferred lighting