HP Workstation zx2000 OpenGL 1.1 Reference for HP-UX 11.x - Page 25

B gluBeginSurface gluBeginSurface gluBeginSurface, gluEndSurface: delimit a NURBS surface definition. C Specification void gluBeginSurface( GLUnurbs* nurb) void gluEndSurface( GLUnurbs* nurb) Parameters nurb Specifies the NURBS object (created with gluNewNurbsRenderer). Description Use gluBeginSurface to mark the beginning of a NURBS surface definition. After calling gluBeginSurface, 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. To mark the end of the NURBS surface definition, call gluEndSurface. Trimming of NURBS surfaces is supported with gluBeginTrim, gluPwlCurve, gluNurbsCurve, andgluEndTrim. See the gluBeginTrim reference page for details. GL evaluators are used to render the NURBS surface as a set of polygons. Evaluator state is preserved during rendering with glPushAttrib(GL_EVAL_BIT) and glPopAttrib(). See the glPushAttrib reference page for details on exactly what state these calls preserve. See Also gluBeginCurve, gluBeginTrim, gluNewNurbsRenderer, gluNurbsCurve, gluNurbsSurface, gluPwlCurve Chapter 2 25