gluLoadSamplingMatrices function

Article
12/11/2020

The gluLoadSamplingMatrices function loads Non-Uniform Rational B-Spline (NURBS) sampling and culling matrices.

Syntax

void WINAPI gluLoadSamplingMatrices(
         GLUnurbs *nobj,
   const GLfloat  modelMatrix[16],
   const GLfloat  projMatrix[16],
   const GLint    viewport[4]
);

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).

Return value

This function does not return a value.

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.)

Requirements

Requirement	Value
Minimum supported client	Windows 2000 Professional [desktop apps only]
Minimum supported server	Windows 2000 Server [desktop apps only]
Header	Glu.h
Library	Glu32.lib
DLL	Glu32.dll