Angle

cos

sin

0

1

0

30

√3/2

1/2

45

√2/2

√2/2

60

1/2

√3/2

90

0

1

 

 

 

1)      (2 points) We have a tiny 8x4 raster screen.  What size frame buffer in bytes is required to store pixel the colors for an RGB system? 8*4*24/8=96 bytes

 

2)      (2 points) Draw the resulting diagram when I make the following GL calls

 

glBegin(GL_LINES);                                            V1

glVertex3fv(vertex1);                                        *

glVertex3fv(vertex2);                            V2*            *V3

glVertex3fv(vertex3);                               V4*   * V5

glVertex3fv(vertex4);

glVertex3fv(vertex5);

       glEnd();

4)  Given the following polyline, shade only the interior regions.   Show all work.

a)      (3 points)Use the odd-even rule.

Crosses even edges exterior

Cross odd edges interior

 

b) (3 points)Use the non-zero winding rule        R to L add one

L to R subtract one

If nonzero, interior                                                       

 

 

 

 

 

 

Line algorithms and anti-aliasing

6)      (5 points)Consider the line from (7 , 2) to (12 , 4).  Use Bresenham’s algorithm to determine the pixels.  Plot on the Raster Screen.  Show all work.

                           7           2       

K         Pk         Xk+1       Yk+1   

  0         -1          8             2

  1         3          9             3

  2         -3           10         3

  1         1             11       4

  4        -5             12      4

 

 

ΔX=5               2ΔX=10          

ΔY=2               2ΔY=4

M < 1   P0 = 2ΔY – ΔX = 4-5=-1

If Pk < 0, plot Xk +1, Yk: Pk+1  = Pk+2ΔY    Pk+1  = Pk+4

Else  plot Xk +1, Yk+1: Pk+1  = Pk+2ΔY-2ΔX

  Pk+1  = Pk+4-10= Pk-2

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

X

X

 

 

 

 

 

 

 

 

 

 

 

X

X

 

 

 

 

 

 

 

 

 

 

 

X

X

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

7)      (5 points) Consider the line from (0 , 3) to (2 , 7).  Use Bresenham’s algorithm to determine the pixels.  Plot on the Raster Screen.  Show all work.

ΔX=2               2ΔX=4             ΔY=4               2ΔY=8

M < 1   P0 = 2ΔX – ΔY = 8-8=0

If Pk < 0, plot Xk, Yk+1 Pk+1  = Pk+2ΔX  Pk+1  = Pk+4

Else  plot Xk +1, Yk+1 Pk+1  = Pk+2ΔX-2ΔY Pk+1  = Pk+4-8= Pk-4

 

 

 

                           0           3       

K         Pk         Xk+1       Yk+1   

  0         0           1             4

  1         -4          1            5

  2         0           2            6

  3       -4            2            7