HP Workstation zx2000 OpenGL 1.1 Reference for HP-UX 11.x - Page 305

N gluNurbsCurve gluNurbsCurve gluNurbsCurve: define the shape of a NURBS curve. C Specification void gluNurbsCurve( GLUnurbs* nurb, GLint knotCount, GLfloat *knots, GLint stride, GLfloat *control, GLint order, GLenum type) Parameters nurb knotCount knots stride control order type Specifies the NURBS object (created with gluNewNurbsRenderer). Specifies the number of knots in knots. knotCount equals the number of control points plus the order. Specifies an array of knotCount non-decreasing knot values. Specifies the offset (as a number of single-precision floating-point values) between successive curve control points. Specifies a pointer to an array of control points. The coordinates must agree with type, specified below. Specifies the order of the NURBS curve. order equals degree + 1, hence a cubic curve has an order of 4. Specifies the type of the curve. If this curve is defined within a gluBeginCurve/gluEndCurve pair, then the type can be any of the valid one-dimensional evaluator types (such as GL_MAP1_VERTEX_3 or GL_MAP1_COLOR_4). Between a gluBeginCurve/gluEndCurve pair, the only valid types are GLU_MAP1_TRIM_2 and GLU_MAP1_TRIM_3. Description Use gluNurbsCurve to describe a NURBS curve. When gluNurbsCurve appears between a gluBeginCurve/gluEndCurve pair, it is used to describe a curve to be rendered. Positional, texture, and color coordinates are associated by presenting each as a separate gluNurbsCurve between a gluBeginCurve/gluEndCurve pair. No more than one call to gluNurbsCurve for each of color, position, and texture data can be made within a single gluBeginCurve/gluEndCurve pair. Exactly one call must be made to describe the position of the curve (a type of GL_MAP1_VERTEX_3 or GL_MAP1_VERTEX_4). Chapter 12 305