Angus Dorbie (dorbie++at++bitch.reading.sgi.com)
Wed, 14 Aug 1996 09:52:00 +0100
So how do you erase the stencil information when you are done? (the extra pass)
Your approach will only work if you don't have any occlusion between
decal surfaces, or if you depth sort.
Angus.
On Aug 13, 10:42am, Michael T. Jones wrote:
> Subject: Re: Flimmering
> On Aug 13, 5:30pm, Angus Dorbie wrote:
> > Subject: Re: Flimmering
> > On Aug 13, 6:20am, Michael T. Jones wrote:
> > > Subject: re: Flimmering
>
> > OK, but don't you also have the overhead of drawing the base polygon more
> > than once for the subface stencil algorithm making this approach expensive.
> >
> > Have I missed a trick here or does this overhead exist?
>
> You draw the base once (set stencil based on Z-compare)
> You then draw the layers one at a time (from bottom to
> top) using stencil to control writing (with Z-compare
> disabled). There is no "extra" pass.
>
> It is true that the polygons underneath the layers are
> "needlessly" rendered -- a cookie-cutter approach that
> chops holes in the underlying geometry would run faster
> in almost all cases.
>
> Michael
>-- End of excerpt from Michael T. Jones
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