OpenGL man pages
glEvalPoint1, glEvalPoint2 - generate and evaluate a single point in a mesh
void glEvalPoint1( GLint i )
void glEvalPoint2( GLint i,
GLint j )
i Specifies the integer value for grid domain variable i.
j Specifies the integer value for grid domain variable j (glEvalPoint2
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·du + u );
du = (u -u )/n
and n, u , and u 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·du + u is exactly u .
In the two-dimensional case, glEvalPoint2, let
du=(u -u )/n
dv=(v -v )/m
where n, u , u , m, v , and v are the arguments to the most recent
1 2 1 2
glMapGrid2 command. Then the glEvalPoint2 command is equivalent to calling
glEvalCoord2(i·du + u , j·dv + v );
The only absolute numeric requirements are that if i = n, then the value
computed from i·du + u is exactly u , and if j = m, then the value
computed from j·dv + v is exactly v .
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
glEvalCoord, glEvalMesh, glMap1, glMap2, glMapGrid
Fri Dec 6 11:18:03 EST 1996
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