- generate and evaluate a single point in a mesh
C SPECIFICATION
PARAMETERS
_param1 Specifies the integer value for grid domain vari-
able i.
_param2 Specifies the integer value for grid domain vari-
able 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./\u+u1 );
where
/\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./\u+u1 is exactly u2.
In the two-dimensional case, glEvalPoint2, let
/\u=(u2-u1)/n
/\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./\u+u1, j./\v+v1 );
The only absolute numeric requirements are that if i=n, then the
value computed from i./\u+u1 is exactly u2, and if j=m, then the
value computed from i./\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