# JNTU B.Tech Examinations, COMPUTER GRAPHICS, Aug/Sep 2008

JNTU III B.Tech Supplimentary Examinations, Aug/Sep 2008

COMPUTER GRAPHICS

(Computer Science & Engineering)

SET-I

1. (a) How much time is spent in scanning across each row of pixels during screen

refresh on a raster system with a resolution of 1280 by 1024 and a refresh rate of 60 frames per second. Assume horizontal and vertical retrace times are negligible.

(b) Discuss about the applications of computer graphics in the area of image

processing.

2. (a) Write an algorithm for generating the intermediate points using Bresenham?s

algorithm when two-end points are given as input.

(b) Write an algorithm for polyline function which calls the above algorithm, given

any number (n) of input points. A single point to be plotted when n=1.

3. (a) Describe the transformation that rotates an object point Q(x,y), ?0 about a

fixed center of rotation p(h,k).

(b) Magnify the triangle with vertices A(0,0), B(1,1) and C(5,2) to twice its size,

while keeping C(5,2) fixed.

4. (a) Explain why the Sutherland-Hodgeman polygon-clipping algorithm works for

only convex clipping regions.

(b) Derive the transformation matrix for window to viewport mapping.

5. (a) Analyse the effect on a B-spline of having in sequence four collinear control

points.

(b) Find the conditions under which two joined Hermite curves have C1 continuity.

6. Prove that the multiplication of three-dimensional transformation matrices for each

of the following sequence of operations is commutative.

(a) Any two successive translations

(b) Any two successive saling operations

(c) Any two successive rotations about any one of the coordinate axes.

7. (a) Distinguish between object-space and image space methods of visible surface

detection algorithms. Give examples for each.

(b) Given points P (1, 2, 0), P (3, 6, 20) P (2, 4, 6) and a view point C (0, 0, -10),

determine which points obscure the others when viewed from C.

8. What are the steps in design of animation sequence? Describe about each step

briefly.