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vpRotate(3)		   Library Functions Manual		   vpRotate(3)

NAME
       vpRotate	- multiply the current transformation matrix by	a rotation ma-
       trix

SYNOPSIS
       #include	<volpack.h>

       vpResult
       vpRotate(vpc, axis, degrees)
	   vpContext *vpc;
	   int axis;
	   double degrees;

ARGUMENTS
       vpc    VolPack context from vpCreateContext.

       axis   Rotation axis code (VP_X_AXIS, VP_Y_AXIS or VP_Z_AXIS).

       degrees
	      Number of	degrees	to rotate.

DESCRIPTION
       vpRotate	is used	to multiply the	current	 transformation	 matrix	 by  a
       4-by-4  rotation	 matrix.   The	rotation axis must be one of the three
       principal viewing axes and is  specified	 with  one  of	the  following
       codes: VP_X_AXIS	     X axis
       VP_Y_AXIS      Y	axis
       VP_Z_AXIS      Z	 axis  The  rotation angle is specified	in degrees.  A
       positive	angle indicates	a clockwise rotation when looking towards  the
       positive	 direction  along the axis.  For an X-axis rotation, the rota-
       tion matrix is:	   1	   0	   0	   0
	   0	cos(d)	sin(d)	   0
	   0	-sin(d)	cos(d)	   0
	   0	   0	   0	   1 where d stands for	the degrees  argument.
       For     a     Y-axis	rotation,     the    rotation	 matrix	   is:
	cos(d)	   0	-sin(d)	   0
	   0	   1	   0	   0
	sin(d)	   0	cos(d)	   0
	   0	   0	   0	   1 For a Z-axis rotation, the	 rotation  ma-
       trix is:	 cos(d)	 sin(d)	    0	    0
	-sin(d)	cos(d)	   0	   0
	   0	   0	   1	   0
	   0	   0	   0	   1

       Use  vpCurrentMatrix  to	set the	current	transformation matrix.	By de-
       fault, the rotation matrix is post-multiplied (M	= M*R where M  is  the
       current	matrix	and R is the rotation matrix).	The VP_CONCAT_MODE op-
       tion to vpSeti can be used to select pre-multiplication.

STATE VARIABLES
       The current matrix concatenation	parameters can be retrieved  with  the
       following  state	 variable  codes  (see	vpGeti(3)): VP_CURRENT_MATRIX,
       VP_CONCAT_MODE.

ERRORS
       The normal return value is VP_OK.  The following	error return value  is
       possible:

       VPERROR_BAD_OPTION
	      The axis argument	is invalid.

SEE ALSO
       VolPack(3), vpCreateContext(3), vpCurrentMatrix(3)

VolPack								   vpRotate(3)
NAME | SYNOPSIS | ARGUMENTS | DESCRIPTION | STATE VARIABLES | ERRORS | SEE ALSO

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