NAME

gluLoadSamplingMatrices - load NURBS sampling and culling matrices

C SPECIFICATION

void gglluuLLooaaddSSaammpplliinnggMMaattrriicceess( GLUnurbs* _n_u_r_b,
                              const GLfloat _*_m_o_d_e_l,
                              const GLfloat _*_p_e_r_s_p_e_c_t_i_v_e,
                              const GLint _*_v_i_e_w )

delim $$

PARAMETERS

_n_u_r_b
Specifies the NURBS object (created with gglluuNNeewwNNuurrbbssRReennddeerreerr).
_m_o_d_e_l
Specifies a modelview matrix (as from a ggllGGeettFFllooaattvv call).
_p_e_r_s_p_e_c_t_i_v_e
Specifies a projection matrix (as from a ggllGGeettFFllooaattvv call).
_v_i_e_w
Specifies a viewport (as from a ggllGGeettIInntteeggeerrvv call).

DESCRIPTION

gglluuLLooaaddSSaammpplliinnggMMaattrriicceess uses _m_o_d_e_l, _p_e_r_s_p_e_c_t_i_v_e, and _v_i_e_w to recompute the sampling and culling matrices stored in _n_u_r_b. The sampling matrix determines how finely a NURBS curve or surface must be tessellated to satisfy the sampling tolerance (as determined by the GGLLUU__SSAAMMPPLLIINNGG__TTOOLLEERRAANNCCEE property). The culling matrix is used in deciding if a NURBS curve or surface should be culled before rendering (when the GGLLUU__CCUULLLLIINNGG property is turned on).

gglluuLLooaaddSSaammpplliinnggMMaattrriicceess is necessary only if the GGLLUU__AAUUTTOO__LLOOAADD__MMAATTRRIIXX property is turned off (see gglluuNNuurrbbssPPrrooppeerrttyy). Although it can be convenient to leave the GGLLUU__AAUUTTOO__LLOOAADD__MMAATTRRIIXX 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.)

SEE ALSO

gglluuGGeettNNuurrbbssPPrrooppeerrttyy((33GG)), gglluuNNeewwNNuurrbbssRReennddeerreerr((33GG)), gglluuNNuurrbbssPPrrooppeerrttyy((33GG))