CSCE 4230  Program #5


        Due date:  Thursday, April 16, 2009


        Write a program that displays the graph of a bivariate function:
        z = f(x,y) for (x,y) in D = [0,1] X [0,1].  Use the following
        test function:

           f(x,y) = .5*exp[-.04*sqrt((80x-40)^2 + (90y-45)^2)] *
                       cos[0.15*sqrt((80x-40)^2 + (90y-45)^2)]

        The user must be able to view the plot from an arbitrary
        perspective (by rotating it about the x and y axes, for example)
        and to zoom in or out.

        Use the following procedure to create a polygonal surface:
        partition D into a k+1 by k+1 uniform rectangular grid, and
        partition each of the k*k squares into a pair of triangles.
        Then call f to obtain a z value at each of the (k+1)^2 grid
        points.

        Use filled triangles with smooth shading and lighting.  Note
        that each vertex normal must be computed by averaging the
        normals of the triangular faces that share the vertex.  Refer
        to "Vertex Arrays" (pp. 65-78) for a means of reducing the
        number of function calls required to render the surface.

        Use double buffering to obtain smooth motion when rotating
        the plot or zooming in or out.

        Use a depth buffer for hidden surface removal.

        Use perspective projection.

        The aspect ratio of the view volume (intersected with the
        projection plane) should be preserved.


        Name your source code file Lastname_5.c or Lastname_5.cpp, 
        where Lastname is your last name, and email it to the grader
        Ismail Mohammed:  im0058@unt.edu.

        Also, hand in a source code listing (with your name on it),
        at the beginning of class on the due date.