GLEVALPOINT(3gl)
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( iu+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 iu+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( iu+u1, jv+v1 );
- The only absolute numeric requirements are that if i=n, then the value com
- puted from iu+u1 is exactly u2, and if j=m, then the value computed from iv+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