Advisor: Dr. Wayne Lang
Computer Science Dept. UNC-A
Abstract
In the CSCI 346 class, Computer Graphics, the OpenGL
library was explored. The class stopped short of exploring lighting
techniques used by OpenGL. My SEnior Project utililizes the techniques
by implementing the different types of lighting. Ambient, specular,
distant, positional, and spot lights were examined in detail. Shadows
were also implemented to add realism to the scene. My project was
done on the alpha UNIX workstations which have the OpenGL libraries
installed.
My method of exploring light with OpenGL started
by rendering a three-dimensional object. I chose the torus because
of its curves enhance the material qualities of the object. I then
declared four different lights to be used on the scene. One is a spotlight
that has only a cone of light. Another is a distant light that shows
the effect of light from a faraway source. The last two lights are
positional lights that emit rays in all directions. Using GLUT, Graphical
Library Utility Toolkit, I made a menu that allows the user to select
which lights are to be used and also their color. Any combination
can be chosen. Shadows are then created by flattening the object onto
the plane in which it is projected. By taking the plane and the position
and direction of the light source, shadows can be created. Three shadows
were cast in this manner and added to the scene. Added to the menu
were choices for the material of the object. These different materials
demonstrate the ambient and specular qualities of the object.
Problems encountered were user, program, and time
constraints. I did not have a user to give me feedback on the program
since this program was not made for any one specific user. I had to
decide what to do and how to do it. I had to be sure the code and
the program were user friendly. There were programming problems as
well. If I made the 3-D object too complex like a teapot, the program
slowed down dramatically. Shadows were sometimes rendered as white,
but I never found out why. If the spotlight is a cone of light, the
bottom shadow turns white. A proven code that was documented would
not work as indicated. Time was the last problem that had to be dealt
with. I had to devise deadlines to make sure intermediate goals were
met. I also had to schedule what work was to be done when I was on
campus because I commute from over an hour away. Scheduling became
very important.
The next step would be the addition of greater input
by the user to control the scene. Slide bars widgets could be added
to control color, material characteristics, and spotlight focusing.
This would allow the user to see exactly what he/she wanted.
Development of this project helped me learn more
about graphical programming and specifically, of OpenGL programming.
It has made me more aware of project management requirements and the
scheduling that needs to be maintained to complete the final project
on time. I was able to successfully program a graphical environment
that allows the user to look at different types of lighting techniques
in detail.
User Manual
"David's Lighting Laboratory" is a program
that uses OpenGL and explores different lighting techniques in a three-dimentional
environment. To run the program, simply double click the icon.
Starting the menu - Move the mouse pointer inside of
the window, and hold the right mouse button until the menu pops up.
Make your selection by moving the mouse pointer over your selection,
which will be highlighted, and release the right mouse button.
Enabling/Disabling a light - Pull up the menu and move
the mouse to the light source you want enabled/disabled. You can choose
"Left Light", "Right Light", "Distant Light",
or "SpotLight". A sub menu will pop up. Select the color you
would like the light to be and release the right mouse button. If you
would like the light turned off, select disable.
Starting/Stopping the object from spinning - Pull up
the menu and select either "stop motion" or "start motion".
Changing the material of the object - Pull up the menu
and select "torus". A submenu will then pop up. Then select
which type of material you want the object to be.
To turn on/off fog - Pull up the menu and select "toggle
fog".
To change the type of fog - Pull up the menu and select
"fog type". A submeny will appear. Then select the type of
fog you want.
To quit - pull up the menu and select "quit".
Download the Executable (This .exe file is fine, but be sure to check
all executables with virus protection.)
Windows
Unix
