BU CLA CS 480: Introduction to Computer Graphics

Spring 1995

Homework Assignment 3---due Friday, April 14

1. Derive an equation for the number of intensities that can be represented by mx m pixel patterns, where each pixel has w bits.

2. You are given the plane parameters A, B, C, and D for all polygons of a closed, convex solid object. Assuming that all the polygon normals point outward, devise an algorithm to determine whether any specified point is inside or outside the object. Will your algorithm work for a concave object? Explain your answer.

3. Determine the quadratic Bézier blending functions for three control points. Plot each function and label the maximum and minimum values.

4. Describe a user interface for picking that lets the user indicate the desired level of a PHIGS hierarchy (for instance, the robot model in the text). Next, give pseudocode that implements this interface. Make sure to specify the PHIGS routines called.