gluLoadSamplingMatrices: load NURBS sampling and culling matrices.
C Specification |
const GLfloat *model,
const GLfloat *perspective,
const GLint *view)
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).
- 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 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.)