GLEVALPOINT(3G) 														   GLEVALPOINT(3G)

NAME

       glEvalPoint1, glEvalPoint2 - generate and evaluate a single point in a mesh

C SPECIFICATION

       void glEvalPoint1( GLint i )
       void glEvalPoint2( GLint i,
			  GLint j )

PARAMETERS

       i  Specifies the integer value for grid domain variable i.

       j  Specifies the integer value for grid domain variable j (glEvalPoint2 only).

DESCRIPTION

       glMapGrid  and glEvalMesh are used in tandem to efficiently generate and evaluate a series of evenly spaced map domain values.  glEvalPoint
       can be used to evaluate a single grid point in the same gridspace that is traversed by glEvalMesh.  Calling glEvalPoint1 is  equivalent	to
       calling

	      glEvalCoord1( i dot DELTA(u) + u1 );
       where

	      DELTA(u) = ( u2 - u1 ) / n

       and  n,	u1, and u2 are the arguments to the most recent glMapGrid1 command.  The one absolute numeric requirement is that if i=n, then the
       value computed from i dot DELTA(u) + u1 is exactly u2.

       In the two-dimensional case, glEvalPoint2, let

	      DELTA(u) = ( u2 - u1 ) / n

	      DELTA(v) = ( v2 - v1 ) / m,

       where n, u1, u2, m, v1, and v2 are the arguments to the most recent glMapGrid2 command.	Then the glEvalPoint2  command	is  equivalent	to
       calling

	      glEvalCoord2( i dot DELTA(u) + u1, j dot DELTA(v) + v1 );
       The  only  absolute  numeric requirements are that if i=n, then the value computed from i dot DELTA(u) + u1 is exactly u2, and if j=m, then
       the value computed from i dot DELTA(v) + v1 is exactly v2.

ASSOCIATED GETS

       glGet with argument GL_MAP1_GRID_DOMAIN
       glGet with argument GL_MAP2_GRID_DOMAIN
       glGet with argument GL_MAP1_GRID_SEGMENTS
       glGet with argument GL_MAP2_GRID_SEGMENTS

SEE ALSO

       glEvalCoord, glEvalMesh, glMap1, glMap2, glMapGrid

																   GLEVALPOINT(3G)