## Homework 2 Clarifications

Problem 1

• Assume for this problem that the image is square and the side length of the image is a power of 2.  (PDF updated on 5/14/11.)

• Assume that the z-pyramid is always current up through the last rendered primitive, and then you do analysis based on introducing a new primitive (triangle).  (PDF updated on 5/17/11.)

• Part (d) has been re-worded for clarity.    (PDF updated on 5/14/11.)

• In part (d), we'll say that intersecting a viewing ray with the triangle is equivalent to rasterizing it.  (PDF updated on 5/17/11.)

Problem 2

• In part (c), the point Q retains its original z-value, but the z-value of the projection plane may now vary.  See re-worded problem statement for part (c) in the updated homework.    (PDF updated on 5/14/11.)

Problem 4

• If a closed form answer is fairly obvious (e.g., a simple product of terms), and you can explain your reasoning clearly, then you do not need to write out a summation.  In other cases, you might need to write out the summation.  In that case, if possible, try to reduce the summation to a closed form answer.  (PDF updated on 5/17/11.)