Computer Graphics Algorithms Quiz 2 Study Questions

William Shoaff

Study Questions

(This is may not be a complete list of questions: Monday, April 1, 2002, 10:00 am)

1.

What is the clipping ``outcode'' of the real points

• (-1, 1/2, 2)
• (2,3, 4)
• (1/2,3/4, 4/5)

2.

What is the clipping ``outcode'' of the homogeneous points

• (-2, 1, 4, 4)
• (2,3, 4, 1)
• (10,15, 16, 20)

3.

Using Blinn's clipping algorithm, show how to clip the line between

• P₀=(-2, 1, 4, 2) and P₂=(2,3, 4, 1)
• $P_0=(15,\,-6,\,6,\,10)$ and P₂=(2, 3, 4, 4)

4.

Show how to map the portion of the view frustrum defined by $-w \leq x \leq w$, $-0.75w \leq y \leq 0.75w$, $0 \leq z \leq w$ into clip space.

5.

Show how to map clip space onto to a viewport (display window) defined by $200 \leq x \leq 400$, $300 \leq y \leq 450$ on a display device with resolution $0 \leq x \leq 1279$ and $0\leq y \leq 1023$.

6.

Using the DDA line algorithm, show how to compute which pixels would be lit to draw the line from pixel

• $(2,\,5)$ to $(10,\,12)$
• $(2,\,5)$ to $(7,\,12)$

7.

Using Bresenham's line algorithm, show how to compute which pixels would be lit to draw the line from pixel

• $(2,\,5)$ to $(10,\,12)$
• $(2,\,5)$ to $(7,\,12)$