Re: Another Long Day Compliments of Object Graphics

["Mark Hadfield" <m.hadfield(at)niwa.cri.nz>]

"David Fanning" <davidf@dfanning.com> wrote in message
MPG.1404bdb94cb56014989bd6@news.frii.com">news:MPG.1404bdb94cb56014989bd6@news.frii.com...

> Basically, I wanted to put the color bar image into
> a polygon, since you can rotate polygons in 3D space,
> but you can't rotate images. (There is no practical
> purpose in rotating a color bar in 3D space that I know
> of, but I always find I learn as much about IDL
> by doing these silly little things as I learn by
> doing something I'm likely to get paid for.)

Plain IDLgrImages are "funny" in other ways. In particular, where images are
involved, visibility is controlled by drawing order, not vertical position.
So moving your colour bar into some other sort of container is a good idea.

> So, it's a simple matter of making the image a texture
> map of the polygon.

When I first tried texture maps I got funny results (odd pixel shapes &
sizes, I think) and reported it as a bug. The answer from RSI tech support
was, "Make sure texture map image sizes are powers of 2." -- Just a warning.

Another atom you could base your colour bar on is an IDLgrPolygon coloured
via VERT_COLORS. That should keep you busy for Another Long Day.

---
Mark Hadfield
m.hadfield@niwa.cri.nz  http://katipo.niwa.cri.nz/~hadfield/
National Institute for Water and Atmospheric Research
PO Box 14-901, Wellington, New Zealand