Re: [Algorithms] texture-based fog idea

[Keith Z.L. <ke...@dr...>]

How about a link to the bitmap, I'd be interested in looking at it.
:-)

Keith
DreamForge

"Pallister, Kim" wrote:

> I have a couple bits to add:
>
> - Brian's got the right way to look at it. A texture is just a lookup table
> for a function. This can be useful for getting HW to do perpixel stuff with
> more complicated functions that add and modulate. e.g. put a sine wave into
> a texture, put noise into a texture.
>
> - I did an example of the above using the matrox g400 bumpenvmap, which is a
> texture dependant lookup (one texture influences the tex coords for the
> lookup of another texture. Feeding a noise texture as the bump map, and a 1D
> sine wave as the other texture, I was able to get something like:
>
> color = Sin(x + noise(x,y))
>
> Which looks like marble. I'm tempted to attach a bitmap to this
> mail(MUST...OBEY...CHARTER)
>
> - Anytime you are doing something with a 1D texture, think about what you
> could do with the other dimension if it were a 2D texture. There are some
> cases where they might be related or independant.
>
> An example: I recently did a test I'll call Kim's Cheezy Terrain Test. I was
> generating a heightfield with a number of octaves of noise, and wanted to do
> the typical 'mountain tops are white, below that is green, etc. Fine, put
> those color values in a 1D texture and that's it. It occurred to me that I
> could modulate that with a gradient on the other access, and do:
>
> vertex.tu = vertex.y * (scale factor)
> vertex.tv = ambient light + Dot product( vertex.normal, light vector)
>
> and I get vertex lighting modulating the terrain colors.
>
> (I know that's a bad example given that vertex lighting is so cheap,
> especially in HW, but I just wanted to make a point)
>
> Kim Pallister
>
> We will find a way or we will make one.
>                      - Hannibal
>
> > -----Original Message-----
> > From: Conor Stokes [mailto:cs...@tp...]
> > Sent: Thursday, July 06, 2000 9:56 AM
> > To: Algorithms List
> > Subject: Re: [algorithms] texture-based fog idea
> >
> >
> > > >One whacky idea I've been playing around with (and to some
> > > >good effect) is actually using a dither pattern built into the
> > > >fog texture. I found with some good dithering effects, the fog
> > > >looked much smoother
> > >
> > > Interesting idea.  How about a DirtyPunk's Column on this?
> > >
> > I'll probably put it in the techfile. I've got a column
> > update in the works
> > :) I know I keep saying that, but honestly I do :)
> >
> > Conor Stokes
> >
> >
> >
>
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