Material Properites Demo

About this demo...

This demo lets you control three material properties: diffuse color, specular color, and shininess. You can choose various objects on which to view the material. You can rotate the objects with your mouse. You can select preset material settings that are supposed to imitate various real materials such as bronze and red plastic. (You can judge for yourself how much these materials look like the real thing.)

The lighting for this demo is a single light that shines directly into the screen. The light is a white light with both diffuse and specular components. (In terms of light properties that haven't been covered yet, the light has diffuse intensity [1,1,1] and specular intensity [0.4,0.4,0.4], and there is no ambient light.) You have no control over the lighting.

Some things to try:

• Check out what the objects look like with all the specular sliders set to zero.
• Set the Shininess to zero and note that it gives specular highlights that cover almost the whole object. It looks pretty bad.
• Note how the highlight changes as you drag the Shininess slider back and forth.
• Try setting the specular color to be very different from the diffuse color, such as a red object with green specular highlights.
• Rotate the objects, and see how the highlight changes; this works especially well with the Torus. What happens to the specular highlight if you look directly down the doughnut hole?
• Lighting calculations in OpenGL 1.1 are done only at the vertices and then the results are interpolated into the interiors of the polygons; see if you can spot how this affects the appearance of the objects.
• Set the diffuse color sliders to maximum, and note that the specular sliders don't have much effect. This is because setting the diffuse color to white means that, where the light is shining directly on an object, the red, green, and blue components of the surface color are already about as large as they can get.