gluLoadSamplingMatrices — load NURBS sampling and culling matrices
void gluLoadSamplingMatrices( | GLUnurbs* | nurb, |
| const GLfloat * | model, | |
| const GLfloat * | perspective, | |
| const GLint * | view); |
nurbSpecifies the NURBS object (created with gluNewNurbsRenderer).
modelSpecifies a modelview matrix (as from a glGetFloatv call).
perspectiveSpecifies a projection matrix (as from a glGetFloatv call).
viewSpecifies 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.)
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