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[Gzz] Re: [Gzz-commits] gzz/gfx demo/paperbasis.py libpaper/texcomb_NV1.
From: |
Tuomas Lukka |
Subject: |
[Gzz] Re: [Gzz-commits] gzz/gfx demo/paperbasis.py libpaper/texcomb_NV1... |
Date: |
Sat, 14 Sep 2002 19:04:15 +0300 |
User-agent: |
Mutt/1.4i |
On Sat, Sep 14, 2002 at 04:32:28PM +0300, Janne Kujala wrote:
> On Sat, Sep 14, 2002 at 03:35:05PM +0300, Tuomas Lukka wrote:
> > On Sat, Sep 14, 2002 at 06:22:28AM -0400, Janne V. Kujala wrote:
> > > Log message:
> > > Create clamped, bordered versions of textures for BasisPaperQuad on
> > > demand; mipmapping is disabled for clamped textures because I couldn't
> > > get it to work correctly (should GL_SGIS_generate_mipmap allow reading
> > > the generated lower LOD texture images?);
> >
> > Why do that and not just turn on GL_SGIS_generate_mipmap on the new
> > textures?
>
> Because the border needs to be one pixel wide on every mipmap level
> (I'm drawing the border to the actual texture image data).
>
> I tried using the border parameter to glTexImage2D, but always got
> totally one-colored textures. Furthermore, the border feature isn't
> very well documented. For example, the border needs to be added to
> width and height parameters but there is no mention whether the
> actual image data should also include the borders.
Jvk: yes, it should. The borders are extra texels that work differently
from the others in mipmapping.
> > > there is still the problem of choosing the texture color outside the
> > > clamped box so that the something is visible when the two textures do not
> > > overlap
> >
> > Yes, it's true that it's not really meaningful; how about just
> > (.5,.5,.5)?
>
> I tried 0, 0.5, and 1.0 but there wasn't much difference.
>
> It would be nice to be able to show the actual dot products
> when the textures do not overlap and do the color interpolation
> only inside the intersection. This would require new combiner code
> or some stencil tricks.
Would be good.
> The band-like texture only uses one dot product
> (and the dot product of the two textures inside the intersection).
>
> For both types, the actual 3-component textures should also be
> shown in addition to the dot products.
Yes, make it so it's easy to flash through them.
> > And maybe drawing clearly colored lines for the boundaries of
> > the basis quads?
>
> That should help but not with the above problems.
No, simply with showing things clearer.
Tuomas