GLUNURBSSURFACE() GLUNURBSSURFACE() NAME gluNurbsSurface - define the shape of a NURBS surface C SPECIFICATION void gluNurbsSurface( GLUnurbs* nurb, GLint sKnotCount, GLfloat* sKnots, GLint tKnotCount, GLfloat* tKnots, GLint sStride, GLint tStride, GLfloat* control, GLint sOrder, GLint tOrder, GLenum type ) delim $$ PARAMETERS nurb Specifies the NURBS object (created with gluNewNurbsRenderer). sKnotCount Specifies the number of knots in the parametric u direction. sKnots Specifies an array of sKnotCount nondecreasing knot values in the parametric u direction. tKnotCount Specifies the number of knots in the parametric v direction. tKnots Specifies an array of tKnotCount nondecreasing knot values in the parametric v direction. sStride Specifies the offset (as a number of single-precision floating point values) between successive control points in the paramet- ric u direction in control. tStride Specifies the offset (in single-precision floating-point val- ues) between successive control points in the parametric v di- rection in control. control Specifies an array containing control points for the NURBS sur- face. The offsets between successive control points in the parametric u and v directions are given by sStride and tStride. sOrder Specifies the order of the NURBS surface in the parametric u direction. The order is one more than the degree, hence a sur- face that is cubic in u has a u order of 4. tOrder Specifies the order of the NURBS surface in the parametric v direction. The order is one more than the degree, hence a sur- face that is cubic in v has a v order of 4. type Specifies type of the surface. type can be any of the valid two-dimensional evaluator types (such as GL_MAP2_VERTEX_3 or GL_MAP2_COLOR_4). DESCRIPTION Use gluNurbsSurface within a NURBS (Non-Uniform Rational B-Spline) surface definition to describe the shape of a NURBS surface (before any trimming). To mark the beginning of a NURBS surface definition, use the gluBeginSur- face command. To mark the end of a NURBS surface definition, use the glu- EndSurface command. Call gluNurbsSurface within a NURBS surface definition only. Positional, texture, and color coordinates are associated with a surface by presenting each as a separate gluNurbsSurface between a gluBeginSur- face/gluEndSurface pair. No more than one call to gluNurbsSurface for each of color, position, and texture data can be made within a single gluBegin- Surface/gluEndSurface pair. Exactly one call must be made to describe the position of the surface (a type of GL_MAP2_VERTEX_3 or GL_MAP2_VERTEX_4). A NURBS surface can be trimmed by using the commands gluNurbsCurve and gluPwlCurve between calls to gluBeginTrim and gluEndTrim. Note that a gluNurbsSurface with sKnotCount knots in the u direction and tKnotCount knots in the v direction with orders sOrder and tOrder must have (sKnotCount - sOrder) $times$ (tKnotCount - tOrder) control points. EXAMPLE The following commands render a textured NURBS surface with normals; the texture coordinates and normals are also NURBS surfaces: gluBeginSurface(nobj); gluNurbsSurface(nobj, ..., GL_MAP2_TEXTURE_COORD_2); gluNurbsSurface(nobj, ..., GL_MAP2_NORMAL); gluNurbsSurface(nobj, ..., GL_MAP2_VERTEX_4); gluEndSurface(nobj); SEE ALSO gluBeginSurface, gluBeginTrim, gluNewNurbsRenderer, gluNurbsCurve, gluPwl- Curve GLUNURBSSURFACE()
NAME | C SPECIFICATION | PARAMETERS | DESCRIPTION | EXAMPLE | SEE ALSO
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