1991-2006
Silicon Graphics, Inc.
gluLoadSamplingMatrices
3G

# gluLoadSamplingMatrices

load NURBS sampling and culling matrices

## C Specification

                    void gluLoadSamplingMatrices
                    GLUnurbs* nurb
                    const GLfloat * model
                    const GLfloat * perspective
                    const GLint * view

## Parameters

`nurb`

  Specifies the NURBS object (created with gluNewNurbsRenderer).

`model`

  Specifies a modelview matrix (as from a glGetFloatv call).

`perspective`

  Specifies a projection matrix (as from a glGetFloatv call).

`view`

  Specifies a viewport (as from a glGetIntegerv call).

## Description

`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.)

## See Also

gluGetNurbsProperty, gluNewNurbsRenderer, gluNurbsProperty

## Copyright

Copyright 1991-2006 Silicon Graphics, Inc. This document is licensed under the SGI Free Software B License. For details, see http://oss.sgi.com/projects/FreeB/.