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<HTML><BODY><PRE> <STRONG>NAME</STRONG> <STRONG>gluNurbsCurve</STRONG> - define the shape of a NURBS curve <STRONG>C</STRONG> <STRONG>SPECIFICATION</STRONG> void <STRONG>gluNurbsCurve</STRONG>( GLUnurbs* <EM>nurb</EM>, GLint <EM>knotCount</EM>, GLfloat *<EM>knots</EM>, GLint <EM>stride</EM>, GLfloat *<EM>control</EM>, GLint <EM>order</EM>, GLenum <EM>type</EM> ) <STRONG>PARAMETERS</STRONG> <EM>nurb</EM> Specifies the NURBS object (created with <STRONG>gluNewNurbsRenderer</STRONG>). <EM>knotCount</EM> Specifies the number of knots in <EM>knots</EM>. <EM>knotCount</EM> equals the number of control points plus the order. <EM>knots</EM> Specifies an array of <EM>knotCount</EM> nondecreasing knot values. <EM>stride</EM> Specifies the offset (as a number of single- precision floating-point values) between successive curve control points. <EM>control</EM> Specifies a pointer to an array of control points. The coordinates must agree with <EM>type</EM>, specified below. <EM>order</EM> Specifies the order of the NURBS curve. <EM>order</EM> equals degree + 1, hence a cubic curve has an order of 4. <EM>type</EM> Specifies the type of the curve. If this curve is defined within a <STRONG>gluBeginCurve</STRONG>/<STRONG>gluEndCurve</STRONG> pair, then the type can be any of the valid one- dimensional evaluator types (such as <STRONG>GL_MAP1_VERTEX_3</STRONG> or <STRONG>GL_MAP1_COLOR_4</STRONG>). Between a <STRONG>gluBeginTrim</STRONG>/<STRONG>gluEndTrim</STRONG> pair, the only valid types are <STRONG>GLU_MAP1_TRIM_2</STRONG> and <STRONG>GLU_MAP1_TRIM_3</STRONG>. <STRONG>DESCRIPTION</STRONG> Use <STRONG>gluNurbsCurve</STRONG> to describe a NURBS curve. When <STRONG>gluNurbsCurve</STRONG> appears between a <STRONG>gluBeginCurve</STRONG>/<STRONG>gluEndCurve</STRONG> pair, it is used to describe a curve to be rendered. Positional, texture, and color coordinates are associated by presenting each as a separate <STRONG>gluNurbsCurve</STRONG> between a <STRONG>gluBeginCurve</STRONG>/<STRONG>gluEndCurve</STRONG> pair. No more than one call to <STRONG>gluNurbsCurve</STRONG> for each of color, position, and texture data can be made within a single <STRONG>gluBeginCurve</STRONG>/<STRONG>gluEndCurve</STRONG> pair. Exactly one call must be made to describe the position of the curve (a <EM>type</EM> of <STRONG>GL_MAP1_VERTEX_3</STRONG> or <STRONG>GL_MAP1_VERTEX_4</STRONG>). When <STRONG>gluNurbsCurve</STRONG> appears between a <STRONG>gluBeginTrim</STRONG>/<STRONG>gluEndTrim</STRONG> pair, it is used to describe a trimming curve on a NURBS surface. If <EM>type</EM> is <STRONG>GLU_MAP1_TRIM_2</STRONG>, then it describes a curve in two-dimensional (<EM>u</EM> and <EM>v</EM>) parameter space. If it is <STRONG>GLU_MAP1_TRIM_3</STRONG>, then it describes a curve in two- dimensional homogeneous (<EM>u</EM>, <EM>v</EM>, and <EM>w</EM>) parameter space. See the <STRONG>gluBeginTrim</STRONG> reference page for more discussion about trimming curves. <STRONG>EXAMPLE</STRONG> The following commands render a textured NURBS curve with normals: gluBeginCurve(nobj); gluNurbsCurve(nobj, ..., GL_MAP1_TEXTURE_COORD_2); gluNurbsCurve(nobj, ..., GL_MAP1_NORMAL); gluNurbsCurve(nobj, ..., GL_MAP1_VERTEX_4); gluEndCurve(nobj); <STRONG>NOTES</STRONG> To define trim curves which stitch well, use <STRONG>gluPwlCurve</STRONG>. <STRONG>SEE</STRONG> <STRONG>ALSO</STRONG> <STRONG>gluBeginCurve</STRONG>, <STRONG>gluBeginTrim</STRONG>, <STRONG>gluNewNurbsRenderer</STRONG>, <STRONG>gluPwlCurve</STRONG></PRE></BODY></HTML>⌨️ 快捷键说明
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