> From: Marcus Traylor <[EMAIL PROTECTED]>
>
> I am trying to find out if I can use Texture 3D to produce a Sphere
> with hills and valleys on it.
> What I need to do do is take 2D data and use it to create a 3D texture
> mapped to a Sphere. The resulting surface
> must respond to the light I have created, and produce shadows and
> highlights where appropriate.
What you are describing here is called "bump mapping". It changes the normals
used in the lighting equations across the area of the primitive using values
from a "bump map". Java3D does not support bump mapping (yet).
3D texture mapping is different. As a form of texture mapping, it is a way of
changing the *color* of the primitive across the primitive's area (as opposed to
changing the *normals* in bump mapping). In 3D texture mapping, three
coordinates are used to specify the location in the texture map which specifies
the color. An example of 3D texture mapping is to generate a volume with a
synthetic "marble" texture. An object drawn using the marble texture would
could then have the marble texture, with the internal marbling being displayed
where the object's surface passes through the texture. In other words, 2D
texture mapping applies a texture like a decal, 3D texture mapping applies a
texture as if the object were carved out of the texture material.
> I have completed the project using a triangle strip array, but its way
> to slow for the size of the data sets I need
> to handle. I am casting about for a more efficient way of doing it. Is
> the Texture3D approach appropriate for my problem?
> Any ideas anyone has would be greatly appreciated.
One approach would be to build a mesh of the full resolution data and then use a
mesh simplification algorithm to reduce the number of triangles.
Doug Gehringer
Sun Microsystems
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