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 . |
||
j |
Specifies the integer value for grid domain variable (glEvalPoint2 only). |
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 );
where
and , , and are the arguments to the most recent glMapGrid1 command. The one absolute numeric requirement is that if , then the value computed from is exactly .
In the two-dimensional case, glEvalPoint2, let
where , , , , , and are the arguments to the most recent glMapGrid2 command. Then the glEvalPoint2 command is equivalent to calling
glEvalCoord2( i , j );
The only absolute numeric requirements are that if , then the value computed from is exactly , and if , then the value computed from is exactly .
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(3G), glEvalMesh(3G), glMap1(3G), glMap2(3G), glMapGrid(3G)