GLEVALPOINT(3G) UNIX Programmer's Manual 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._\_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
MirBSD #10-current Printed 2021-12-07 1
GLEVALPOINT(3G) UNIX Programmer's Manual GLEVALPOINT(3G)
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
SEE ALSO
glEvalCoord(3G), glEvalMesh(3G), glMap1(3G), glMap2(3G),
glMapGrid(3G)
MirBSD #10-current Printed 2021-12-07 2