Re: surface transparency

Hi Gaoming,

> I used Gridded2DSet to draw a topography surface. I also want to draw some 
> street lines on the surface. Each street line has some points with
> only x and y, I used valueToInterp method to interpolate these points to get 
> z values, then draw these points as one line. My problem is, some
> segment of the line are below the surface. So I want my topography surface to 
> be transparent so that every thing below the surface can be seen
> clearly. I tried the following:
> dispGMC = (GraphicsModeControl)display.getGraphicsModeControl();
> dispGMC.setTransparencyMode(;

The last time I tired screen door, it didn't work. I'd delete
these statements.

> zMap   = new ScalarMap(Z, Display.RGB);
> display.addMap(zMap);
> display.addMap(new ScalarMap(Z, Display.Alpha));

Instead of mapping Z -> Alpha, try a ConstantMap to Alpha.
Or replace the ScalarMap of Z -> RGB with Z -> RGBA, then
set alpha values in the table of the ColorControl.

Good luck,
Bill Hibbard, SSEC, 1225 W. Dayton St., Madison, WI  53706
hibbard@xxxxxxxxxxxxxxxxx  608-263-4427  fax: 608-263-6738