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))