Z-Buffer FAQ?

So, what is the downside of all this additional precision? Larger memory hit? Takes more bandwidth?

 

Basically, and really you definately don't want to be using 16 bit Z-Precision anymore (well unless you are messing around with something that is really low poly count where as well the polys aren't close together).

 

Okay, but say then 24bit compared to 24bit 8bit. What's the up and down sides to going with the additional 8bit stencil over plain old 24bit?

 

Heh as far as I know just that you get a stencil buffer. Either way you have to read you data 32 bits at a time. It could be possible those 8 bits really get used in some other way to help performance but I don't know. Also not sure on this but it might be easier to do Z-Buffer compression when you don't have stencil bits since thats 8 less bits you have to worry about trying to compress.

 

The stencil buffer is a programmer's tool. It's not related directly to turning on any performance or effects.

 

So even if I select a mode in radlinker, where there is not this 8 bit stencil listed, I will still get stencil shadows when game requests such a thing?

 

I think it's likely that you'll find that, in the above cases, if you haven't enabled the stencil, the 24 bit Z data will still be put into 32bit units and the remaining 8 bits ignored. Its the same with 24bit colour.

 

I don't think the game would be able to run its stencil algorithm if the stencil buffer is disabled, no.

 

From what I can gather, there seems little point in selecting anything other than 16,24,8bit stencil?