Share via

gluLoadSamplingMatrices

  • Article

The gluLoadSamplingMatrices function loads NURBS sampling and culling matrices.

void gluLoadSamplingMatrices(
  GLUnurbsObj *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).

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

**  Windows NT/2000:** Requires Windows NT 3.5 or later.
**  Windows 95/98:** Requires Windows 95 or later. Available as a redistributable for Windows 95.
**  Header:** Declared in Glu.h.
**  Library:** Use Glu32.lib.

See Also

glGetFloatv, glGetIntegerv, gluGetNurbsProperty, gluNewNurbsRenderer