glGetMap

GLGETMAP(3G)							 GLGETMAP(3G)



NAME
       glGetMapdv, glGetMapfv, glGetMapiv - return evaluator parameters


C SPECIFICATION
       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
       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
       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 func-
		      tion.  One-dimensional evaluators return order  control
		      points,	 and	two-dimensional	  evaluators   return
		      uorder×vorder control points.  Each control point	 con-
		      sists  of one, two, three, or four integer, single-pre-
		      cision 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 float-
		      ing-point values to the nearest integer values.

       GL_ORDER	      v returns the order of the  evaluator  function.	 One-
		      dimensional  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.	 One-
		      dimensional 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
       If an error is generated, no change is made to the contents of v.

ERRORS
       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
       glEvalCoord(3G), glMap1(3G), glMap2(3G)



								 GLGETMAP(3G)