.\" @(#)PEXViewOrientationMatrix2D.3 1.4 95/03/24 SMI;
.so man3/pex.macs
.TH PEXViewOrientationMatrix2D 3 "May 1995" "Solaris PEXlib Reference Manual" ""
.SH NAME
PEXViewOrientationMatrix2D - utility function
.SH SYNTAX
.HP
int PEXViewOrientationMatrix2D\^(\^PEXCoord2D *\fIvrp\fP, PEXVector2D *\fIvup\fP, PEXMatrix3x3 \fImatrix_return\fP\^)
.SH PARAMETERS
.IP \fIvrp\fP 1i
View reference point.
.IP \fIvup\fP 1i
View up vector.
.IP \fImatrix_return\fP 1i
Matrix into which result is stored.
.SH RETURNS
.LP
Zero if successful; otherwise, one of the following:
.TP
.B PEXBadVector
.I vup
is zero length.
.SH DESCRIPTION
.\" indexing
.IX PEXViewOrientationMatrix2D
.LP
This function creates a view orientation matrix that
transforms world coordinates (WC) to view reference
coordinates (VRC).  This matrix is used in conjunction with a view
mapping matrix as the viewing matrices for a designated view.
.LP
The view reference point (VRP) defines the point in world
coordinate space that is to be used as the origin of the
view reference coordinate system.  The point is in
the WC z=0 plane.
.LP
The view plane normal (VPN) is in the direction of the positive
Z axis of WC.
.LP
The view up vector (VUP) is a 2D vector in the WC z=0 plane.
It determines the positive Y axis of VRC.  It's defined in
world coordinates relative to the view reference point.
.LP
The X axis of VRC is defined such that the VRC system
forms a right-handed coordinate system.
.SH ERRORS
.LP
None
.SH SEE ALSO
.LP
.nf
.BR PEXViewOrientationMatrix (3)
.BR PEXViewMappingMatrix (3)
.BR PEXViewMappingMatrix2D (3)
.fi