Re: An interpolation question...

• To: "Wilson, Andrew, J" <andrew.wilson@xxxxxxxxxxxx>
• Subject: Re: An interpolation question...
• From: Bill Hibbard <hibbard@xxxxxxxxxxxxxxxxx>
• Date: Thu, 06 Feb 2003 16:00:22 -0600

"Wilson, Andrew, J" wrote:
> 
> Can I just check I am not missing something here?
> 
> Right now I am displaying a data set that has 11 slices, each
> of which is 250 samples x 2001 samples.
> 
> With setTextureEnable(true) I can quite quickly flick through
> the slices using the VisAd animation support. This is really
> very nice and I (and my boss) were impressed with how quickly
> this could be implemented.
> 
> But the display is blocky and my users are used to nice
> smooth displays. Sigh.
> 
> If I create my display with DisplayImpJ2D then
> setTextureEnable(false) eventually delivers a nice smoothed
> image but is very, very slow.

DisplayImplJ2D should be fast if you use a Linear2DSet without
any CoordinateSystem, and with ScalarMaps to Cartesian spatial
DisplayRealTypes (i.e., XAxis, etc). But slow if you use a
Gridded2DSet, a CoordinateSystem, or ScalarMaps to non-Cartesian
spatial DisplayRealTypes.

> If I create my display with DisplayImplJ3D("display1", new
> TwoDDisplayRendererJ3D());
> then I just get a blank screen when I
> setTextureEnable(false).

If two programs are identical except for whether they
pass true or false to setTextureEnable(), and the one
with true shows an image and the one with false has a
blank screen, then that's a bug. However, this has all
been so thoroughly exercised that its hard to believe.

> Can I get the speed of Texture mapped rendering with the
> smoothness of interpolation?

A DisplayImplJ3D with setTextureEnable(false) should be
a lot faster than the same thing in a DisplayImplJ2D, but
not as fast as with texture mapping.

> Do I have to guesstimate how many screen pixels are on show
> and resample myself?

It is a recurring theme in visualization, that the
best performance requires more complexity in
applications. The approach you describe would
probably help.

But first re-examine your use of DisplayImplJ3D with
setTextureEnable(false) that produces the blank display.
It sounds like there's either a bug in VIsAD or a bug
in your program.

Good luck,
Bill

• Follow-Ups:
  • Re: An interpolation question...
    • From: Helen Yi

• References:
  • RE: An interpolation question...
    • From: Wilson, Andrew, J