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Up: 16.2 Volume Visualization with
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Using 3D textures for volume rendering is the most desirable method. The slices
can be oriented perpendicular to the viewer's line of sight, and creating
spherical slices for close-up views doesn't lead to sampling errors.
Here are the steps for rendering a volume using 3D textures:
- 1.
- Load the volume data into a 3D texture. This is done once for a particular
data volume.
- 2.
- Choose the number of slices, based on the criteria in
Section 16.2.5. Usually this matches the texel
dimensions of the volume data cube.
- 3.
- Find the desired viewpoint and view direction.
- 4.
- Compute a series of polygons that cut through the data perpendicular
to the direction of view. Use texture coordinate generation to texture the
slice properly with respect to the 3D texture data.
- 5.
- Use the texture transform matrix to set the desired orientation of
the textured images on the slices.
- 6.
- Render each slice as a textured polygon, from back to front. A blend
operation is performed at each slice; the type of blend depends on the
desired effect. See the blend equation descriptions in
Section 16.2.4 for details.
- 7.
- As the viewpoint and direction of view changes, recompute the data slice
positions and update the texture transformation matrix as necessary.
Next: 16.2.3 2D Texture Volume
Up: 16.2 Volume Visualization with
Previous: 16.2.1 Overview of the
David Blythe
1999-08-06