Computer Graphics with Open GL

Donald Hearn. M. Pauline. Baker, Warren R.Carithers

Chapter 18

Interactive Input Methods and Graphical User Interfaces - all with Video Answers

Educators

Chapter Questions

Problem 1

Design an algorithm that allows objects to be positioned on the screen using a locator device. An object menu of geometric shapes is to be presented to a user who is to select an object and a placement position. The program should allow any number of objects to be positioned until a "terminate" signal is given.

Brian Ketelobeter

Brian Ketelobeter

Numerade Educator

Problem 2

Extend the algorithm of the previous exercise so that selected objects can be scaled and rotated before positioning. The transformation choices and transformation parameters are to be presented to the user as menu options.

Farnood Ensan

Numerade Educator

Problem 3

Set up a procedure for interactively sketching pictures using a stroke device.

ag

Alan Ghazarians

Numerade Educator

Problem 4

Discuss the methods that could be employed in a pattern-recognition procedure to match input characters against a stored library of shapes.

Adriano Chikande

Adriano Chikande

Numerade Educator

Problem 5

Write a routine that displays a linear scale and a slider on the screen and allows numeric values to be selected by positioning the slide along the scale line. The selected numeric value is to be echoed in a box displayed near the linear scale.

Brian Ketelobeter

Brian Ketelobeter

Numerade Educator

Problem 6

Write a program that makes use of the slider developed in the previous exercise to allow the user to scale an object displayed in a display window between some minimum and maximum value.

Morgan Cheatham

Morgan Cheatham

Numerade Educator

Problem 7

Write a routine that displays a circular scale and a pointer or a slider that can be moved around the circle to select angles (in degrees). The angular value selected is to be echoed in a box displayed near the circular scale.

Shelby Mohamed

Numerade Educator

Problem 8

Write a program that makes use of the circular slider developed in the previous exercise to allow the user to rotate an object around its center.

Aaron Goree

Numerade Educator

Problem 9

Write a drawing program that allows users to create a picture as a set of straight-line segments drawn between specified endpoints. The coordinates of the individual line segments are to be selected with a locator device.

Morgan Cheatham

Morgan Cheatham

Numerade Educator

Problem 10

Write a drawing package that allows pictures to be created with straight-line segments drawn between specified endpoints. Set up a gravity field around each line in a picture, as an aid in connecting new lines to existing lines.

Jay Patel

Numerade Educator

Problem 11

Modify the drawing package in the previous exercise so that lines can be constrained horizontally or vertically.

Christine Anacker

Christine Anacker

Numerade Educator

Problem 12

Develop a drawing package that can display an optional grid pattern so that selected screen positions are rounded to grid intersections. The package is to provide line-drawing capabilities, with line endpoints selected using a locator device.

Brian Ketelobeter

Brian Ketelobeter

Numerade Educator

Problem 13

Write a routine that allows a designer to create a picture by sketching straight lines using a rubberband method.

Jay Patel

Numerade Educator

Problem 14

Design a drawing package that allows straight lines, rectangles, and circles to be constructed using rubber-band methods.

Jay Patel

Numerade Educator

Problem 15

Write a procedure that allows a user to pick components of a two-dimensional scene. The coordinate extents for each object are to be stored and used to identify the picked object, given an input cursor position.

Morgan Cheatham

Morgan Cheatham

Numerade Educator

Problem 16

Develop a procedure that allows a user to design a picture from a menu of displayed basic shapes by dragging each selected shape into position with a pick device.

Brian Ketelobeter

Brian Ketelobeter

Numerade Educator

Problem 17

Design an implementation of the input functions for request mode.

Victor Salazar

Numerade Educator

Problem 18

Design an implementation of the sample mode input functions.

Yujie Wang

College of San Mateo

Problem 19

Design an implementation of the input functions for event mode.

Nick Johnson

Numerade Educator

Problem 20

Design a procedure for implementing input functions for request, sample, and event mode.

Matt Gibson

Numerade Educator

Problem 21

Expand the OpenGL point-plotting program in Section 6 to include a menu that allows a user to select point size and point color.

Lucas Finney

Numerade Educator

Problem 22

Expand the OpenGL polyline program in Section 6 to include a menu that allows a user to choose the line attributes: size, color, and width.

Aatish Gupta

Numerade Educator

Problem 23

Modify the program in the preceding exercise to allow a texture pattern to be chosen for the polyline.

Sheryl Ezze

Numerade Educator

Problem 24

Write an interactive OpenGL program to display a circle of radius 150 that can be at any input position within a display window. The input position is to be the center of the circle. Include a menu of color options for displaying the circle in a solid color.

Aaron Goree

Numerade Educator

Problem 25

Modify the program in the preceding exercise so that the input position is rejected if the entire circle cannot be displayed within the display window:

Erika Bustos

Numerade Educator

Problem 26

Modify the program in the preceding exercise to include a menu of texture options for the circle. Include a solid color texture, a gradient texture, and a minimum of two other texture pattems.

Wendi Zhao

Numerade Educator

Problem 27

Set up an interactive OpenGL program for displaying an input character string at any position within a display window. The input position is the starting position for the text.

Harriet O'Brien

Harriet O'Brien

Numerade Educator

Problem 28

Write an interactive OpenGL program for positioning a single two-dimensional object at any position within a display window. The object is to be selected from a menu of basic shapes, including (minimally) a square, circle, and triangle.

Morgan Cheatham

Morgan Cheatham

Numerade Educator

Problem 29

Modify the program in the preceding exercise to allow any arrangement of the two-dimensional objects to be displayed, with each object selected from the menu until a quit option is chosen frum the menu.

Alex Bretton

Numerade Educator

Problem 30

Modify the program in the preceding exercise to allow objects to be scaled or rotated. Geometric transformation operations are to be listed in a menu.

Farnood Ensan

Numerade Educator

Problem 31

Write an interactive OpenGL program for positioning a single three-dimensional object within a display window. The object is to be selected frum a menu list of GLUT wire-frame solids, such as a sphere, solid, or cylinder, and it is to be centered on an input position.

Morgan Cheatham

Morgan Cheatham

Numerade Educator

Problem 32

Modify the program in the preceding exercise to allow the objects to be displayed in either a wireframe or solid form. For solid-object displays, include a point light source at the viewing position, and use default parameters for the illumination and surface shading-

VS

Vivek Singh

Numerade Educator

Problem 33

Write a program to implement the OpenGL picking operations for a three-dimensional scene containing several objects. For each pick selection, create a small pick window and remove the most distant object within that pick window from the scene, replacing it with a new object at a random location in the scene.

Morgan Cheatham

Morgan Cheatham

Numerade Educator

Problem 34

Write an interactive OpenGL program to display a two-dimensional cubic Bezier curve. The four control-point positions are to be selected with mouse input.

Morgan Cheatham

Morgan Cheatham

Numerade Educator

Problem 35

Modify the program in the preceding exercise to display a Bézier curve with a selected degree of three, four, or five.

Sarah Wharton

Numerade Educator

Problem 36

Write an interactive OpenGL program to display a two-dimensional cubic B-spline. The spline parameters are to be given as input, and the control points are to be selected with a mouse.

Morgan Cheatham

Morgan Cheatham

Numerade Educator

Problem 37

Write an interactive OpenGL program to display a cubic Bézier surface patch. The $x$ and $y$ coordinates for the control points can be selected with a mouse, and the z coordinate can be given as a height above a ground plane.

Sriram Soundarrajan

Sriram Soundarrajan

Numerade Educator

Problem 38

Select some graphics application with which you are familiar and set up a user model that will serve as the basis for the design of a user interface for graphics applications in that area.

Jennifer Stoner

Jennifer Stoner

Numerade Educator

Problem 39

List possible help facilities that can be provided in a user interface and discuss which types of help would be appropriate for different levels of users.

Steven Brown

Numerade Educator

Problem 40

Summarize the methods for handling backup and errors. Which methods are suitable for a beginner? Which methods are better for an experienced user?

Adam Conner

Numerade Educator

Problem 41

List the possible formats for presenting menus to a user, and explain under what circumstances each might be appropriate.

Carson Merrill

Numerade Educator

Problem 42

Discuss alternatives for feedback in terms of the various levels of users.

Joanna Quigley

Numerade Educator

Problem 43

List the functions that must be performed by a window manager in handling screen layouts with multiple, overlapping windows.

Adam Conner

Numerade Educator

Problem 44

Set up a design for a window-manager package.

Connor Hudson

Numerade Educator

Problem 45

Design a user interface for a painting program.

Grant Castaneda

Grant Castaneda

Numerade Educator

Problem 46

Design a user interface for a two-level hierarchical modeling package.

SS

Sarvesh Somasundaram

Numerade Educator