void gluLoadSamplingMatrices( GLUnurbs* nurb,
const GLfloat *model, const GLfloat *perspective, const GLint *view )
Specifies the NURBS object (created with gluNewNurbsRenderer).
Specifies a modelview matrix (as from a glGetFloatv call).
Specifies a projection matrix (as from a glGetFloatv call).
Specifies a viewport (as from a glGetIntegerv call).
gluLoadSamplingMatrices uses model, perspective, and view to recompute the sampling and culling matrices stored in nurb. The sampling matrix determines how finely a NURBS curve or surface must be tessellated to satisfy the sampling tolerance (as determined by the GLU_SAMPLING_TOLERANCE property). The culling matrix is used in deciding if a NURBS curve or surface should be culled before rendering (when the GLU_CULLING property is turned on).
gluLoadSamplingMatrices is necessary only if the GLU_AUTO_LOAD_MATRIX property is turned off (see gluNurbsProperty). Although it can be convenient to leave the GLU_AUTO_LOAD_MATRIX property turned on, there can be a performance penalty for doing so. (A round trip to the GL server is needed to fetch the current values of the modelview matrix, projection matrix, and viewport.)
gluGetNurbsProperty(3G), gluNewNurbsRenderer(3G), gluNurbsProperty(3G)