100 lines
3.3 KiB
Plaintext
100 lines
3.3 KiB
Plaintext
'\" e
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'\"! eqn | mmdoc
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'\"macro stdmacro
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.ds Vn Version 1.2
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.ds Dt 6 March 1997
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.ds Re Release 1.2.0
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.ds Dp May 02 11:53
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.ds Dm 37 nurbscurv
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.ds Xs 25594 5 nurbscurve.gl
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.TH GLUNURBSCURVE 3G
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.SH NAME
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.B "gluNurbsCurve
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\- define the shape of a NURBS curve
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.SH C SPECIFICATION
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void \f3gluNurbsCurve\fP(
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GLUnurbs* \fInurb\fP,
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.nf
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.ta \w'\f3void \fPgluNurbsCurve( 'u
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GLint \fIknotCount\fP,
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GLfloat \fI*knots\fP,
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GLint \fIstride\fP,
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GLfloat \fI*control\fP,
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GLint \fIorder\fP,
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GLenum \fItype\fP )
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.fi
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.EQ
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delim $$
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.EN
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.SH PARAMETERS
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.TP \w'\fIknotCount\fP\ \ 'u
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\f2nurb\fP
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Specifies the NURBS object (created with \%\f3gluNewNurbsRenderer\fP).
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.TP
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\f2knotCount\fP
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Specifies the number of knots in \f2knots\fP.
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\f2knotCount\fP equals the number of control points plus the order.
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.TP
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\f2knots\fP
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Specifies an array of \f2knotCount\fP nondecreasing knot values.
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.TP
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\f2stride\fP
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Specifies the offset (as a number of single-precision floating-point values)
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between successive curve control points.
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.TP
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\f2control\fP
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Specifies a pointer to an array of control points. The coordinates must
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agree with \f2type\fP, specified below.
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.TP
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\f2order\fP
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Specifies the order of the NURBS curve. \f2order\fP equals degree + 1, hence
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a cubic curve has an order of 4.
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.TP
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\f2type\fP
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Specifies the type of the curve. If this curve is defined within a
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\%\f3gluBeginCurve\fP/\%\f3gluEndCurve\fP pair, then
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the type can be any of the valid
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one-dimensional evaluator types (such as \%\f3GL_MAP1_VERTEX_3\fP or
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\%\f3GL_MAP1_COLOR_4\fP). Between a \%\f3gluBeginTrim\fP/\%\f3gluEndTrim\fP pair,
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the only valid types are \%\f3GLU_MAP1_TRIM_2\fP and \%\f3GLU_MAP1_TRIM_3\fP.
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.SH DESCRIPTION
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Use \%\f3gluNurbsCurve\fP to describe a NURBS curve.
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.P
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When \%\f3gluNurbsCurve\fP appears between a \%\f3gluBeginCurve\fP/\%\f3gluEndCurve\fP pair, it is
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used to describe a curve to be rendered.
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Positional, texture, and color coordinates are associated
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by presenting each as a separate \%\f3gluNurbsCurve\fP between a
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\%\f3gluBeginCurve\fP/\%\f3gluEndCurve\fP pair. No more than
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one call to \%\f3gluNurbsCurve\fP for each of color, position, and texture
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data can be made within a single \%\f3gluBeginCurve\fP/\%\f3gluEndCurve\fP
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pair. Exactly one call must be made to describe the position of the
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curve (a \f2type\fP of \%\f3GL_MAP1_VERTEX_3\fP or \%\f3GL_MAP1_VERTEX_4\fP).
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.P
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When \%\f3gluNurbsCurve\fP appears between a \%\f3gluBeginTrim\fP/\%\f3gluEndTrim\fP pair, it is
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used to describe a trimming curve on a NURBS surface. If \f2type\fP is
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\%\f3GLU_MAP1_TRIM_2\fP, then it describes a curve in two-dimensional (\f2u\fP
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and \f2v\fP)
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parameter space. If it is \%\f3GLU_MAP1_TRIM_3\fP, then it describes a
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curve in two-dimensional homogeneous (\f2u\fP, \f2v\fP, and \f2w\fP)
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parameter space.
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See the \%\f3gluBeginTrim\fP reference page for more discussion about trimming
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curves.
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.SH EXAMPLE
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The following commands render a textured NURBS curve with normals:
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.sp
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.Ex
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gluBeginCurve(nobj);
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gluNurbsCurve(nobj, ..., GL_MAP1_TEXTURE_COORD_2);
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gluNurbsCurve(nobj, ..., GL_MAP1_NORMAL);
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gluNurbsCurve(nobj, ..., GL_MAP1_VERTEX_4);
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gluEndCurve(nobj);
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.Ee
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.sp
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.SH NOTES
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To define trim curves which stitch well, use \%\f3gluPwlCurve\fP.
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.SH SEE ALSO
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\%\f3gluBeginCurve(3G)\fP, \%\f3gluBeginTrim(3G)\fP, \%\f3gluNewNurbsRenderer(3G)\fP, \%\f3gluPwlCurve(3G)\fP
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