Re: [Gzz-commits] gzz/gfx demo/paperbasis.py libpaper/texcomb_NV1...

[Janne Kujala]

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.

> > 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.

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.

> And maybe drawing clearly colored lines for the boundaries of
> the basis quads?

That should help but not with the above problems.

        jvk