section of routines in demo2.i

functions in demo2.i -

 
 
 
demo2


             demo2  
 
     Exhibit quadrilateral mesh plots in 3 movies of a drumhead.  
     The drumhead is initially stationary, but has a bump near one  
     edge.  Yorick is solving a 2D wave equation to compute the  
     evolution of this bump.  
     The first movie is a filled mesh plot with color "proportional"  
     to the height of the surface of the drum.  A few well chosen  
     contour levels (here 3) add a lot to a filled mesh plot.  
     The second movie is a "3D" perspective plot of the height of the  
     drumhead.  In this movie, the mesh lines are drawn, which is  
     slightly confusing since the cells are not all the same shape.  
     The second movie is a "3D" shaded plot of the height of the  
     drumhead.  Yorick computes surface shading based on the angle  
     of each cell from a light source.  
     As you watch this, you might reflect on the two dimensionality  
     of your retina.  What Yorick lacks by way of 3D graphics is  
     really just fancy hidden surface algorithms; the simple  
     painter's algorithm used here and in plwf.i is easy to  
     implement.  
     There are two optional arguments to demo2: the first is the  
     number fo the movie (1, 2, or 3) you want to watch; the second  
     is a time limit on the duration of each movie in seconds (default  
     is 60 seconds each).