CSE 167 - Introduction to Computer Graphics - Fall 2004
Instructor: Sam Buss,  Univ. of California, San Diego

Project #4 - Add lights and materials to your scene. 

Due Date: Tuesday, November 9, midnight.

Goals: Use illumination and shading to make your scene from project #3 look more three-dimensional.  Learn how to shade objects with the Phong lighting model in OpenGL.  Create three lights, two or more materials.  Add keyboard controls to your program.

What to hand in:  (1) Make a directory called LightedScene in your CSE 167 storage directory.  (The CSE 167 home directory on ieng9, under Class Resources, not your "My Documents" folder).   Place, in that directory, all your source files and project files (including .sln and .vcproj files).
    (2) You must upload also, a thumbnail GIF file, a full size screenshot and a very simple HTML file.  This will collect the entire class's projects into a web page that will be made accessible on the web.
    As usual, grading will be personalized and one-on-one with a TA or with Sam Buss.  Your program must run on the PC lab, you must come into the PC lab and meet one of us.  You will have to show your source code, run the program, possibly make changes on the spot to your program and recompile as requested by the grader, and be able to explain how your program works and why it renders what it does. Your files should be complete and project must recompile in the ieng9 directory.   Grading must be done within two weeks of the due date, preferably earlier.

FOR THIS PROJECT #4, DO THE FOLLOWING STEPS #1 - #9.

1. Download PC executable from the web, at http://www.math.ucsd.edu/~sbuss/CourseWeb/CSE167_2004F/LightedScene.exe.   Run the executable file on a PC.  You will see a scene with a surface of rotation and a letter "S".  Now there are also three lights (shown as three spheres) and the surfaces show Phong lighting effects, including specular highlights.   The LightedScene program supports all the old controls from WireFrameScene plus some new ones:

• Pressing the arrow keys changes the view position.  The rate of movement is controlled by pressing the "R" or "r" key to increase or decrease the step size for movements.
• Pressing the "w" key toggles wire frame mode. 
• Pressing the "c" key toggles culling of back faces. 
• Pressing the "M" or "m" increases or decreases the mesh resolution on the surface of rotation..
• Pressing "s" toggles the use of smooth shading and flat shading.  The objects look faceted under flat shading, but the facets disappear (somewhat) under smooth shading.
• Pressing the "1", "2" and "3" keys (one at a time) toggles the three lights off and on.
• Pressing the "h" switches between
      (a) positional lights and a local viewer
      (b) directional lights and a non-local viewer.
• Press the escape key to exit.

Experiment with all of these controls.  Try increasing and decreasing the mesh fineness while switching back and forth between smooth and flat shading modes.  Notice how the specular highlights change size and position when you toggle the "h" command -- understand why this happen.  Rotate slowly around the object in smooth and flat shading modes -- note how a little bit of the faceting can be seen even in smooth mode, especially if the mesh size is not very high.

Your job is to re-create this program -- but with your own three-dimensional geometry from Programming assignment #3. 

2. Form a new project and workspace -- call it LightedScene.  Copy YOUR files from Project #3 and include them in the project LightedScene (you will probably wish to rename the source files too).     For information on how to build a new project, read this handout on starting a new Visual .NET program.

3. Add three lights and ambient lighting.

• When positional, they should be placed at <-5, 5, 0>,  <0,5,0> and  <5,6,0> (you may change these positions slightly, depending on your geometries from Project #3).  When the lights are directional, they should have l vectors equal to these three vectors.  
• In addition to placing light sources at these position, add three small spheres that show the positions of the lights (these spheres' materials have emission properties that cause them to be visible).  These spheres are visible if the light is turned on and is positional. 
• One of the lights must be white.  One of the lights must be colored.  You are free to choose the same color, another color or white for the third light.
• Also, add some low-level ambient light so that objects can be faintly seen with all three lights turned off.

4. Keyboard controls "1", "2" and "3" toggle these lights off and on.  Add these controls to the myKeyboardFunc routine.  glEnable(GL_LIGHTi)  and glDisable(GL_LIGHTi),  for i = 0, 1,2, are the relevant commands to turn lights on and off.

5. Give objects in your scene materials and material properties. 

• You do not need to match the materials in the supplied executable.  Feel free to choose your own colors.
• There must be at least two different materials in the scene.
• You will need to add normal vectors for the vertices in the surface of rotation (step #6) before it will look good.
• Specular highlights must be visible on the surface of rotation and on other materials.  White (or gray) is usually the best choice for the specular color.  The specular exponent values of your materials should not be higher than 127.   Note: Specular will not show up on your surface of rotation until you specify normals for its vertices (see step 6).
• The three-dimensional geometries based on your first initial must have a material and show specular highlights.
• It will take some careful work adjusting the material properties and the light properties to make the scene look good.
• Part of adjusting the lights and materials is setting the scene to not be too dark or too light.  If it is too light, you may not realize it at first: symptoms of being too light include not being able to see good specular highlights or have the surface look "flat" or "washed out".  These are caused when final color values are clamped to the maximum value of 1.0.

6.  Give normal vectors for the vertices in your surface of rotation.  (Normal vectors are automatically given for the built-in glut Solid Objects.  If you built some custom geometries you probably need to add normal vectors for them too.)
        - You probably will need to use the glEnable(GL_NORMALIZE) command (why???).

7. Add the keyboard command "s" that toggles between flat and smooth shading mode for all materials in the scene.

8. Add the "h" keyboard command to toggle between the two modes:
    Mode (a) with positional lights and local viewer, and mode (b) with directional lights and non-local viewer.

9. Make a screenshot and a thumbnail gif, then turn everything in.    Reminder: you must turn in both (1) files to the CSE167 storage directory, including source files and project files and (2) files that uploaded to the common class web page using the Project Four upload page.    This must include a thumb.gif file and a JPEG screenshot image as in Project #3.  For your index.html file, modify the one used for handing in Project #3.

10. Extra credit items (up to a total of 1/2 point extra credit only):  
        (a) Learn how to apply textures on your own (we will discuss in it class later) and give the base plane an attractive texture. 
        Or, (b) Add a spotlight to the demo and show it off effectively.

Grading is on a scale of 1-10.