glEvalPoint(3G)glEvalPoint(3G)NAME
glEvalPoint, glEvalPoint1, glEvalPoint2 - generate and evaluate a sin‐
gle point in a mesh
SYNOPSIS
void glEvalPoint1(
GLint i ); void glEvalPoint2(
GLint i,
GLint j );
PARAMETERS
Specifies the integer value for grid domain variable i. Specifies the
integer value for grid domain variable j (glEvalPoint2() only).
DESCRIPTIONglMapGrid() and glEvalMesh() are used in tandem to efficiently generate
and evaluate a series of evenly spaced map domain values. glEval‐
Point() 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 . DELTA u + u[1] );
where
DELTA u = ( u[2] - u[1] ) / n
and n, u[1], and u[2] 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 . DELTA u + u[1] is exactly u[2].
In the two-dimensional case, glEvalPoint2, let
DELTA u = u[2] - u[1] ) / n
DELTA v = ( v[2] - v[1] ) / m,
where n, u[1], u[2], m, v[1], and v[2] are the arguments to the most
recent glMapGrid2() command. Then the glEvalPoint2() command is equiva‐
lent to calling
glEvalCoord2( i . DELTA u + u[1], j. DELTA v + v[1] );
The only absolute numeric requirements are that if i=n, then the value
computed from i . DELTA u + u[1] is exactly u[2], and if j=m, then the
value computed from i . DELTA v + v[1] is exactly v[2].
ASSOCIATED GETSglGet() 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 ALSOglEvalCoord(3), glEvalMesh(3), glMap1(3), glMap2(3), glMapGrid(3)glEvalPoint(3G)