<BR> Use a cylindrical mapping method. The point of intersection
is projected onto an imaginary cylinder, and the location
of the projected point is used to determine the texture coordinates.
If given, <tex2html_verbatim_mark>#math159#<tex2html_image_mark>#tex2html_wrap_inline5056#⇧ and
<tex2html_verbatim_mark>#math160#<tex2html_image_mark>#tex2html_wrap_inline5058#⇧ define the cylinder's axis, and <tex2html_verbatim_mark>#math161#<tex2html_image_mark>#tex2html_wrap_inline5060#⇧ defines
where <I>u</I> = 0 is located.
</DD>
</DL>See the description of the inverse mapping method for the
cylinder in Chapter 5. By default, the point of intersection is
projected onto a cylinder that runs through the origin along the <I>z</I>
axis, with <tex2html_verbatim_mark>#math162#<tex2html_image_mark>#tex2html_wrap_inline5064#⇧ equal to the <I>x</I> axis.
<BR> Use a spherical mapping method. The intersection point is
projected onto an imaginary sphere, and the location of the
projected point is used to determine the texturing coordinates
in a manner identical to that used in the inverse mapping method
for the sphere primitive.
If given, the center of
the projection is <tex2html_verbatim_mark>#math166#<tex2html_image_mark>#tex2html_wrap_inline5074#⇧, <tex2html_verbatim_mark>#math167#<tex2html_image_mark>#tex2html_wrap_inline5076#⇧ defines
the sphere axis, and the point where the
non-parallel <tex2html_verbatim_mark>#math168#<tex2html_image_mark>#tex2html_wrap_inline5078#⇧ intersects the sphere
defines where <I>u</I> = 0 is located.
</DD>
</DL>By default, a spherical mapping projects points towards the origin,
with <tex2html_verbatim_mark>#math169#<tex2html_image_mark>#tex2html_wrap_inline5081#⇧ defined to be the <I>z</I> axis and
<tex2html_verbatim_mark>#math170#<tex2html_image_mark>#tex2html_wrap_inline5084#⇧ defined to be the <I>x</I> axis.