On Wed, 23 Feb 2005 21:43:01 -0500, Daniel Phillips <[EMAIL PROTECTED]> wrote:
> On Wednesday 23 February 2005 20:40, Timothy Miller wrote:
> > On Wed, 23 Feb 2005 19:34:42 -0500, I wrote:
> > > Trilinear blending...
> >
> > I'm quite certain it's in there.  I also know for a fact that it's in
> > the model.
> 
> Oh right, GL_LINEAR_MIPMAP_LINEAR.
> 
> > > A trilinear blend is two bilinear blends lerped together.  This
> > > totals 56 multiplies.  We probably can't afford that much real
> > > estate for this feature.  I propose to modify the bilinear hardware
> > > to do this at half clock speed, with 4 additional multipliers.
> >
> > It doesn't require that many multiplies, actually.  Since only two
> > pixels come in per clock, only one multiply has to be done per clock
> > to blend them.
> 
> But on four color components.  What did I miss?

You missed that I can be an idiot sometimes.  :)

> 
> > ...There are two sets of texture registers, but there is only
> > one texture unit that can read only two pixels per clock from RAM.
> 
> I've been wondering about that.  Why do we bother interpolating two
> textures times two pixels per clock if we can only texture at half that
> rate?  Wouldn't it make sense to interpolate fewer parameters per clock
> and alternate the pipeline when somebody turns modulation on?

We can texture AT that rate if we use only one texture and use NEAREST filter.
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