glGetMap(3G)		       OpenGL Reference			  glGetMap(3G)

NAME    [Toc]    [Back]

     glGetMapdv, glGetMapfv, glGetMapiv	- return evaluator parameters

C SPECIFICATION    [Toc]    [Back]

     void glGetMapdv( GLenum target,
		      GLenum query,
		      GLdouble *v )
     void glGetMapfv( GLenum target,
		      GLenum query,
		      GLfloat *v )
     void glGetMapiv( GLenum target,
		      GLenum query,
		      GLint *v )

PARAMETERS    [Toc]    [Back]

     target  Specifies the symbolic name of a map.  Accepted values are
	     GL_MAP1_COLOR_4, GL_MAP1_INDEX, GL_MAP1_NORMAL,
	     GL_MAP1_TEXTURE_COORD_1, GL_MAP1_TEXTURE_COORD_2,
	     GL_MAP1_TEXTURE_COORD_3, GL_MAP1_TEXTURE_COORD_4,
	     GL_MAP1_VERTEX_3, GL_MAP1_VERTEX_4, GL_MAP2_COLOR_4,
	     GL_MAP2_INDEX, GL_MAP2_NORMAL, GL_MAP2_TEXTURE_COORD_1,
	     GL_MAP2_TEXTURE_COORD_2, GL_MAP2_TEXTURE_COORD_3,
	     GL_MAP2_TEXTURE_COORD_4, GL_MAP2_VERTEX_3,	and GL_MAP2_VERTEX_4.

     query   Specifies which parameter to return.  Symbolic names GL_COEFF,
	     GL_ORDER, and GL_DOMAIN are accepted.

     v	     Returns the requested data.

DESCRIPTION    [Toc]    [Back]

     glMap1 and	glMap2 define evaluators.  glGetMap returns evaluator
     parameters.  target chooses a map,	query selects a	specific parameter,
     and v points to storage where the values will be returned.

     The acceptable values for the target parameter are	described in the
     glMap1 and	glMap2 reference pages.

     query can assume the following values:

     GL_COEFF	    v returns the control points for the evaluator function.
		    One-dimensional evaluators return order control points,
		    and	two-dimensional	evaluators return uorder x vorder
		    control points.  Each control point	consists of one, two,
		    three, or four integer, single-precision floating-point,
		    or double-precision	floating-point values, depending on
		    the	type of	the evaluator.	The GL returns two-dimensional
		    control points in row-major	order, incrementing the	uorder
		    index quickly and the vorder index after each row.
		    Integer values, when requested, are	computed by rounding
		    the	internal floating-point	values to the nearest integer



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glGetMap(3G)		       OpenGL Reference			  glGetMap(3G)



		    values.

     GL_ORDER	    v returns the order	of the evaluator function.  Onedimensional
	evaluators return a single value, order. The
		    initial value is 1.	 Two-dimensional evaluators return two
		    values, uorder and vorder. The initial value is 1,1.

     GL_DOMAIN	    v returns the linear u and v mapping parameters.  Onedimensional
	evaluators return two values, u1 and u2, as
		    specified by glMap1.  Two-dimensional evaluators return
		    four values	(u1, u2, v1, and v2) as	specified by glMap2.
		    Integer values, when requested, are	computed by rounding
		    the	internal floating-point	values to the nearest integer
		    values.

NOTES    [Toc]    [Back]

     If	an error is generated, no change is made to the	contents of v.

ERRORS    [Toc]    [Back]

     GL_INVALID_ENUM is	generated if either target or query is not an accepted
     value.

     GL_INVALID_OPERATION is generated if glGetMap is executed between the
     execution of glBegin and the corresponding	execution of glEnd.

SEE ALSO    [Toc]    [Back]

     glEvalCoord, glMap1, glMap2


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