gluLoadSamplingMatrices
[New
- Windows 95, OEM Service Release 2]
The gluLoadSamplingMatrices function loads
NURBS sampling and culling matrices.
void gluLoadSamplingMatrices(
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GLUnurbsObj *nobj, |
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const GLfloat modelMatrix[16], |
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const GLfloat projMatrix[16], |
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const GLint viewport[4] |
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); |
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Parameters
nobj
The NURBS
object (created with gluNewNurbsRenderer).
modelMatrix
A modelview
matrix (as from a glGetFloatv
call).
projMatrix
A projection
matrix (as from a glGetFloatv call).
viewport
A viewport
(as from a glGetIntegerv
call).
Remarks
The gluLoadSamplingMatrices function uses modelMatrix,
projMatrix, and viewport to recompute the sampling and culling
matrices stored in nobj. 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).
The gluLoadSamplingMatrices function 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, doing so
necessitates a round trip to the OpenGL server to get the current values of the
modelview matrix, projection matrix, and viewport.)
See Also