| |
| | The Z-Buffer Device |
 | | When used for 3-D graphics, two buffers are present: an 8-bit-deep frame buffer that contains the picture; and a 16-bit-deep Z-buffer of the same resolution, containing the z-value of the visible surface of each pixel. |
 | | The normal procedure is to set the graphics device to "Z", draw the objects, read the frame buffer, and then select another graphics device and write the image. |
 | | The values in the depth buffer are short integers, scaled from -32765 to +32765, corresponding to normalized Z-coordinate values of 0.0 to 1.0. |
| www.physics.nyu.edu /grierlab/idl_html_help/devices18.html (758 words) |
|