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Re: Why do I get a grey display ?

The likely cause is a limitation in the OpenGL + your graphics card. On my machine, a PC running Windows, there is an apparently limit of 1024 in either dimension of a texturemap -- if I exceed that limit, the result is a gray rectangle. The only work-around I know of is to resample your image to a lower resolution. This is currently the singularly most inhibiting problem with displaying images that I'm aware of. I believe the 'solution' should be a resampling "under the hood", but apparently until Java3D is able to correctly determine the limit imposed by the OpenGL + graphics card properly (and could/should therefore automatically resample as needed) this is the only thing I know to do.
(An example of this resampling can be found in the Jython code for 'graph.py' in the 'image()' method.)
I believe you could also use 2D for the display, but the performance is pretty bad (at least on my PC). 

tom

Helen Yi wrote:


Hi

I have two datasets, one is 350x700 another is 900x1500.
I use the alomost same VisAD code to display them in Lat-Lon 2D domain,
except the length of data samples is different,


     display = new DisplayImplJ3D("display", new
TwoDDisplayRendererJ3D());

     latMap = new ScalarMap(RealType.Latitude, Display.YAxis);
     lonMap = new ScalarMap(RealType.Longitude, Display.XAxis);
     display.addMap(latMap);
     display.addMap(lonMap);

     imageValue = RealType.getRealType("image");
     rgbMap = new ScalarMap(imageValue, Display.RGB);
     display.addMap(rgbMap);

     imageRef = new DataReferenceImpl("image");
     display.addReference(imageRef);

     .........

I could get a color display for dataset with less data samples but a
grey display for the large dataset.

The interest thing is:
when I click on the display (since  PointManipulationRendererJ3D has
been added to the above display), I could get the correct lat, lon and
data value at the point I have clicked.

Does anyone know why I end up with a grey display for the larger
dataset?

By the way, I am on SGI IRIX with
2  600 MHZ IP30 Processors
CPU: MIPS R14000 Processor Chip Revision: 2.4
FPU: MIPS R10010 Floating Point Chip Revision: 0.0
Main memory size: 1536 Mbytes

java version "1.3.1"
Java(TM) 2 Runtime Environment, Standard Edition (build
1.3.1-mtibuild-011130-22:40)
Classic VM (build 1.3.1-mtibuild-011130-22:40, native threads, mipsjit)

Java 3D 1.2.1 from SGI

Thanks for your great  help.
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