gluLoadSamplingMatrices.3gl

Name

  gluLoadSamplingMatrices - load NURBS sampling	and culling matrices

C Specification

  void gluLoadSamplingMatrices(	GLUnurbsObj *nobj,

				const GLfloat modelMatrix[16],

				const GLfloat projMatrix[16],

				const GLint viewport[4]); )

Parameters

  nobj	       Specifies the NURBS object (created with	gluNewNurbsRenderer).



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



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



  viewport;    Specifies a viewport (as	from a glGetIntegerv call).

Description

  gluLoadSamplingMatrices 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).



  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 OpenGL server

  is needed to fetch the current values	of the modelview matrix, projection

  matrix, and viewport.)

See Also

  gluGetNurbsProperty, gluNewNurbsRenderer, gluNurbsProperty

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Last Edited: Mon, May 22, 1995

AFV