CS116a Fall 2004Practice Final

[Student generated solutions]

To study for the midterm I would suggest you: (1) Know how to do (by heart) all the practice problems. (2) Go over your notes three times. Second and third time try to see how huch you can remember from the first time. (3) Go over the homework problems. (4) Try to create your own problems similar to the ones I have given and solve them. (5) Skim the relevant sections from the book. (6) If you want to study in groups, at this point you are ready to quiz each other. The practice final is below.

Here are some facts about the actual final: (a) The final will be in class Thursday, Dec 16 from 12:15-14:30 in SCI164. (b) It is closed book, closed notes. Nothing will be permitted on your desk except your pen (pencil) and test. (c) You should bring photo ID. (d) There will be more than one version of the test. Each version will be of comparable difficulty. (e) If your cell-phone or beeper goes off you will be excused from the test at that point and graded on what you have done till your excusal. (f) There will be ten problems on the final. (g) One problem (less typos) on the actual test will be from the practice test. (h) There will be two problems from before Midterm I, (i) There will be two problems from the material from Midterm I to II. (j) All remaining problems will be from after Midterm II.

1. Briefly describe how the Phong lighting model works.

2. Suppose I want to look at the point (2,3,4) from the point (6, 9, 12) and up should be in the direction (0, 1, 0) what should my viewing coordinate transformation be?

3. In 2D suppose I have a clipping window with coordinates (10, 10) and (100, 100) what is the transformation matrix which maps it into the symmetric normalization square?

4. Give the OpenGL commands with all their parameters to: (1) set the viewport, (2) position a window, (3) resize a window.

5. Imagine that you have the triangle with vertices (-.5, 1.5), (1.5, .5), (2,2). Explain how the Cohen-Sutherland algorithm could be used to clip this triangle to the symmetric normalized square.

6. Repeat problem (5) but use the Liang-Barsky algorithm.

7. Repeat problem (5) but use Sutherland-Hodgman.

8. Define the following terms and draw an example which illustrate them: (a) An isometeric projection, (b) An oblique orthogonal projection, (3) a 3 principle vanishing points projection.

9. Draw the pyramid of vision (starting at the origin) and the viewing frustrum for a symmetric perspective projection with field of view angle 45 degrees, aspect ratio 10, zprp - zvp = 1, and with a far plane at 5. Assume the near plane and the clipping window at the same z-offset.

10. Explain how 3D-region codes work.