CS 371
Computer Graphics
Spring 2005

Assignment 6

Due by BEGINNING OF CLASS on 5/6/05

Problem 1
Required:
The text and class notes provide a complete description (derivation of all relevant quantities, plus code) of the case of Bresenham's line drawing algorithm for segments ((xL,yL),(xR,yR)) with xL < xR and having slope m, 0 <= m <= 1. Provide a complete description of the case of Bresenham's algorithm in which xL < xR and the slope m satisfies -1 <= m <= 0 (so, in particular, yL >= yR).
Problem 2
Challenge problem for extra credit:
Develop an algorithm in the spirit of Bresenham's algorithm for circles. You need only consider a circle of integer radius R centered at the origin. Focus your attention on the portion of the circle corresponding to angles between 45-90 degrees counter-clockwise of the positive x-axis. On this part of the circle, there should be exactly one pixel for each x-value. Can you get rid of all floating-point operations? How many additions and multiplications does your algorithm require?
lenhart@cs.williams.edu