gl.EvalPoint(i[, j])
gl.EvalPoint()
can be used to evaluate a single grid point
in the same gridspace that is traversed by gl.EvalMesh(). Calling gl.EvalPoint()
with a single
argument is equivalent to calling
gl.EvalCoord(i*du+u1) |
where
du = (u2-u1)/n |
and n, u1, and u2 are the arguments to the most recent gl.MapGrid() command. The one absolute numeric requirement is that if i = n, then the value computed from i*du+u1 is exactly u2.
In the two-dimensional case, gl.EvalPoint()
, let
du = (u2-u1)/n dv = (v2-v1)/m |
where n, u1, u2, m, v1, and v2 are the arguments to the most recent gl.MapGrid() command. Then the
gl.EvalPoint()
command is equivalent to calling
gl.EvalCoord(i*du+u1, j*dv+v1) |
The only absolute numeric requirements are that if i = n, then the value computed from i*du+u1 is exactly u2, and if j = m, then the value computed from j*dv+v1 is exactly v2.
Please consult an OpenGL reference manual for more information.
#GL_MAP1_GRID_DOMAIN
gl.Get() with argument #GL_MAP2_GRID_DOMAIN
gl.Get() with argument #GL_MAP1_GRID_SEGMENTS
gl.Get() with argument #GL_MAP2_GRID_SEGMENTS