Hidden-line removal works correctly for the problem in Exercise 6.1 because the vertical line passes through edges of the triangles produced by triangulation of the square. Change the horizontal...

Hidden-line removal works correctly for the problem in Exercise 6.1 because

the vertical line passes through edges of the triangles produced by triangulation of the square. Change the horizontal square to a horizontal triangle and use

HLines.java to display the object with the same vertical line through the

triangle. The object may not be displayed properly like those in Fig. 6.16.

Explain why and find a simple solution.