SPHROTMATRIX(3L)					      SPHROTMATRIX(3L)

NAME    [Toc]    [Back]

     sphrotmatrix - orient spheres

C SPECIFICATION    [Toc]    [Back]

     #include <gl/sphere.h>

     void sphrotmatrix(mat)
     Matrix mat;

PARAMETERS    [Toc]    [Back]

     mat    the	rotation matrix	to specify the orientation of the sphere

DESCRIPTION    [Toc]    [Back]

     sphrotmatrix specifies the	rotation matrix	sphdraw	uses for displaying
     spheres with a fixed orientation when the sphere attribute, SPH_ORIENT,
     is	TRUE.  The orientation of the sphere is	applied	by the Sphere Library
     before any	scaling	for radius or translation to the location sent to
     sphdraw.  The matrix provided must	be a pure rotation matrix  or the
     results will be unpredictable. When SPH_ORIENT is TRUE, the Sphere
     Library assumes uniform scaling; the effects of nonuniform	scaling	are
     undefined.

SEE ALSO    [Toc]    [Back]

     libsphere,	sphmode, sphobj, sphdraw, sphgnpolys, sphfree

NOTE    [Toc]    [Back]

     sphrotmatrix can be used to reduce	lighting effects when rotating objects
     that contain spheres.  It can also	be used	on a VGX, in combination with
     the accumulation buffer, to antialias spheres. For	performance, when
     SPH_ORIENT	is TRUE, use the SPH_HEMI attribute to draw only the frontfacing
 half of the	sphere.


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