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gluBeginSurface, gluEndSurface

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The gluBeginSurface and gluEndSurface functions delimit a NURBS surface definition.

void gluBeginSurface(
  GLUnurbsObj *nobj);void gluEndSurface(  GLUnurbsObj *nobj);

Parameters

Remarks

The gluBeginSurface and gluEndSurface functions mark the beginning and end of NURBS surface definitions, which are defined with calls to gluNurbsSurface.

To define a NURBS surface

  1. Call gluBeginSurface to mark the beginning of a NURBS surface definition.

  2. Make one or more calls to gluNurbsSurface to define the attributes of the surface.

    Exactly one of these calls to gluNurbsSurface must have a surface type of GL_MAP2_VERTEX_3 or GL_MAP2_VERTEX_4.

  3. To mark the end of the NURBS surface definition, call gluEndSurface.

The gluBeginTrim, gluPwlCurve, gluNurbsCurve, and gluEndTrim functions support trimming of NURBS surfaces.

Use OpenGL evaluators to render the NURBS surface as a set of polygons. Preserve the evaluator state during rendering with glPushAttrib(GL_EVAL_BIT) and glPopAttrib.

Example

The following functions render a textured NURBS surface with normals; the texture coordinates and normals are also described as NURBS surfaces:

gluBeginSurface(nobj); 
    gluNurbsSurface(nobj, . . ., GL_MAP2_TEXTURE_COORD_2); 
    gluNurbsSurface(nobj, . . ., GL_MAP2_NORMAL); 
    gluNurbsSurface(nobj, . . ., GL_MAP2_VERTEX_4); 
gluEndSurface(nobj);

Requirements

**  Windows NT/2000:** Requires Windows NT 3.5 or later.
**  Windows 95/98:** Requires Windows 95 or later. Available as a redistributable for Windows 95.
**  Header:** Declared in Glu.h.
**  Library:** Use Glu32.lib.

See Also

gluBeginCurve, gluBeginTrim, gluNewNurbsRenderer, gluNurbsCurve, gluNurbsSurface, gluPwlCurve