nurb:SetProperty(property, value)

#GLU_NURBS_MODE

value should be set to be either #GLU_NURBS_RENDERER or #GLU_NURBS_TESSELLATOR. When set to #GLU_NURBS_RENDERER, NURBS objects are tessellated into OpenGL primitives and sent to the pipeline for rendering. When set to #GLU_NURBS_TESSELLATOR, NURBS objects are tessellated into OpenGL primitives but the vertices, normals, colors, and/or textures are retrieved back through a callback interface (See nurb:Callback for details.). This allows the user to cache the tessellated results for further processing. The initial value is #GLU_NURBS_RENDERER.

#GLU_SAMPLING_METHOD

Specifies how a NURBS surface should be tessellated. value may be one of #GLU_PATH_LENGTH, #GLU_PARAMETRIC_ERROR, #GLU_DOMAIN_DISTANCE, #GLU_OBJECT_PATH_LENGTH, or #GLU_OBJECT_PARAMETRIC_ERROR. When set to #GLU_PATH_LENGTH, the surface is rendered so that the maximum length, in pixels, of the edges of the tessellation polygons is no greater than what is specified by #GLU_SAMPLING_TOLERANCE.

#GLU_PARAMETRIC_ERROR specifies that the surface is rendered in such a way that the value specified by #GLU_PARAMETRIC_TOLERANCE describes the maximum distance, in pixels, between the tessellation polygons and the surfaces they approximate.

#GLU_DOMAIN_DISTANCE allows users to specify, in parametric coordinates, how many sample points per unit length are taken in u, v direction.

#GLU_OBJECT_PATH_LENGTH is similar to #GLU_PATH_LENGTH except that it is view independent; that is, the surface is rendered so that the maximum length, in object space, of edges of the tessellation polygons is no greater than what is specified by #GLU_SAMPLING_TOLERANCE.

#GLU_OBJECT_PARAMETRIC_ERROR is similar to #GLU_PARAMETRIC_ERROR except that it is view independent; that is, the surface is rendered in such a way that the value specified by #GLU_PARAMETRIC_TOLERANCE describes the maximum distance, in object space, between the tessellation polygons and the surfaces they approximate.

The initial value of #GLU_SAMPLING_METHOD is #GLU_PATH_LENGTH.

#GLU_SAMPLING_TOLERANCE

Specifies the maximum length, in pixels or in object space length unit, to use when the sampling method is set to #GLU_PATH_LENGTH or #GLU_OBJECT_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 or in object space length unit, to use when the sampling method is #GLU_PARAMETRIC_ERROR or #GLU_OBJECT_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 can be set to #GLU_OUTLINE_POLYGON, #GLU_FILL, or #GLU_OUTLINE_PATCH. When #GLU_NURBS_MODE is set to be #GLU_NURBS_RENDERER, value defines how a NURBS surface should be rendered. 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.

When #GLU_NURBS_MODE is set to be #GLU_NURBS_TESSELLATOR, value defines how a NURBS surface should be tessellated. When #GLU_DISPLAY_MODE is set to# GLU_FILL or #GLU_OUTLINE_POLYGON, the NURBS surface is tessellated into OpenGL triangle primitives that can be retrieved back through callback functions. If #GLU_DISPLAY_MODE is set to #GLU_OUTLINE_PATCH, only the outlines of the patches and trim curves are generated as a sequence of line strips that can be retrieved back through callback functions.

The initial value is #GLU_FILL.

#GLU_CULLING

value is a boolean value that, when set to #GLU_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 #GLU_FALSE.

#GLU_AUTO_LOAD_MATRIX

value is a boolean value. When set to #GLU_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 tessellation 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 #GLU_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 nurb:LoadSamplingMatrices() function. This mode is initially set to #GLU_TRUE. Changing it from #GLU_TRUE to #GLU_FALSE does not affect the sampling and culling matrices until nurb:LoadSamplingMatrices() is called.

If #GLU_AUTO_LOAD_MATRIX is true, sampling and culling may be executed incorrectly if NURBS routines are compiled into a display list.

Please consult an OpenGL reference manual for more information.

property

specifies the property to be set (see above)

value

specifies the value of the indicated property (see above)