Thursday, October 27, 2011

Diffuse, Ambient, and Specular Lighting

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...

No comments:

Post a Comment