glEvalPoint(3gl)

1GLEVALPOINT(3G)                                                GLEVALPOINT(3G)
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NAME

6       glEvalPoint1,  glEvalPoint2 - generate and evaluate a single point in a
7       mesh
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9

C SPECIFICATION

11       void glEvalPoint1( GLint i )
12       void glEvalPoint2( GLint i,
13                          GLint j )
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15

PARAMETERS

17       i  Specifies the integer value for grid domain variable i.
18
19       j  Specifies the integer value for grid domain variable j (glEvalPoint2
20          only).
21

DESCRIPTION

23       glMapGrid and glEvalMesh are used in tandem to efficiently generate and
24       evaluate a series of evenly spaced map domain values.  glEvalPoint  can
25       be  used  to evaluate a single grid point in the same gridspace that is
26       traversed by glEvalMesh.  Calling glEvalPoint1 is equivalent to calling
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28              glEvalCoord1( i⋅Δu+u1 );
29where
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31              Δu=(u2−u1)/n
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33
34and n, u1, and u2 are the arguments to the  most  recent  glMapGrid1  command.
35The  one  absolute numeric requirement is that if i=n, then the value computed
36from i⋅Δu+u1 is exactly u2.
37
38In the two-dimensional case, glEvalPoint2, let
39
40       Δu=(u2−u1)/n
41
42       Δv=(v2−v1)/m,
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44where n, u1, u2, m, v1, and v2 are the arguments to the most recent glMapGrid2
45command.  Then the glEvalPoint2 command is equivalent to calling
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47       glEvalCoord2( i⋅Δu+u1, j⋅Δv+v1 );
48The  only  absolute  numeric requirements are that if i=n, then the value com‐
49puted from i⋅Δu+u1 is exactly u2, and if j=m, then  the  value  computed  from

i⋅Δv+v1 is exactly v2.

ASSOCIATED GETS

53       glGet with argument GL_MAP1_GRID_DOMAIN
54       glGet with argument GL_MAP2_GRID_DOMAIN
55       glGet with argument GL_MAP1_GRID_SEGMENTS
56       glGet with argument GL_MAP2_GRID_SEGMENTS
57

NAME

C SPECIFICATION

PARAMETERS

DESCRIPTION

i⋅Δv+v1 is exactly v2.

ASSOCIATED GETS

SEE ALSO