Since you either have covered this recently or will very soon, I will repost this information about lighting from last year's blog in case it helps you out.
I have another applet I wrote a while back that might be useful to you. 
 It demonstrates the various kinds of lighting and can really help you 
understand what's happening behind the equations.
 
In class you learned about diffuse, ambient, and specular lighting.  
Diffuse lighting comes from a direct light source like the sun, while 
ambient lighting is just what's hanging around in the environment.  
Highlights on a surface from the direct light source appear as specular 
highlights and depend on where your eye is positioned relative to the 
surface.
In my applet, you can adjust the intensities of the red, green, and blue
 light coming from the ambient and direct light sources.  You can also 
adjust the surface reflectance, which determines how much of a certain 
colour of light will be reflected back from the surface (and eventually 
reach your eye, making the material look like a certain colour).  If the
 surface does not reflect any blue, then changing the blue intensity on 
the lights won't affect anything (the only exception being for the 
specular highlight, since those are made before the light would be 
absorbed/reflected in the surface anyway).
You can move the sun (direct light source) and the eye (viewpoint/camera
 centre), and you can tilt the surface to see how the angle between its 
normal and the other directions changes the outcome.
I recommend trying to isolate each type of light first to see how they 
look.  Turn the specular highlight off at first as well.  Then try to 
compare what you see with the equations involved in defining the light 
sources.
As always, if you have any questions, comment here or email me!
Go to the applet now...
 
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