HP b2600 Reference Manual page 308

N
gluNurbsPrperty
Specifies the maximum length, in pixels to use when the sampling method is set to
GLU_PATH_LENGTH. The NURBS code is conservative when rendering a curve or
surface, so the actual length can be somewhat shorter. The initial value is 50.0 pixels.
GLU_PARAMETRIC_TOLERANCE
Specifies the maximum distance, in pixels, to use when the sampling method is
GLU_PARAMETRIC_ERROR. The initial value is 0.5.
GLU_U_STEP
Specifies the number of sample points per unit length taken along the u axis in
parametric coordinates. It is needed when GLU_SAMPLING_METHOD is set to
GLU_DOMAIN_DISTANCE. The initial value is 100.
GLU_V_STEP
Specifies the number of sample points per unit length taken along the v axis in
parametric coordinate. It is needed when GLU_SAMPLING_METHOD is set to
GLU_DOMAIN_DISTANCE. The initial value is 100.
GLU_DISPLAY_MODE
value defines how a NURBS surface should be rendered. value can be set to
GLU_OUTLINE_POLYGON, GLU_FILL, or GLU_OUTLINE_PATCH. When value is
set to GLU_FILL, the surface is rendered as a set of polygons. When value is set to
GLU_OUTLINE_POLYGON the NURBS library draws only the outlines of the polygons
created by tessellation. When value is set to GLU_OUTLINE_PATCH just the outlines of
patches and trim curves defined by the user are drawn. The initial value is GLU_FILL.
GLU_CULLING
value is a boolean value that, when set to GL_TRUE, indicates that a NURBS curve
should be discarded prior to tessellation if its control points lie outside the current
viewport. The initial value is GL_FALSE.
GLU_AUTO_LOAD_MATRIX
value is a boolean value. When set to GL_TRUE, the NURBS code downloads the
projection matrix, the modelview matrix, and the viewport from the GL server to
compute sampling and culling matrices for each NURBS curve that is rendered.
Sampling and culling matrices are required to determine the tesselation of a NURBS
surface into line segments or polygons and to cull a NURBS surface if it lies outside the
viewport.
If this mode is set to GL_FALSE, then the program needs to provide a projection matrix,
a modelview matrix, and a viewport for the NURBS renderer to use to construct
sampling and culling matrices. This can be done with the gluLoadSamplingMatrices
function. This mode is initially set to GL_TRUE. Changing it from GL_TRUE to
GL_FALSE does not affect the sampling and culling matrices until
gluLoadSamplingMatrices is called.
Notes
If GLU_AUTO_LOAD_MATRIX is true, sampling and culling may be executed
incorrectly if NURBS routines are compiled into a display list.
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Chapter 12