light, material, blending
I found out why my cone didn’t not close in my previous exercise. I had to make the upper limit of the angle bigger than 2PI to make the triangle fan close up. This still does not make sense since I used angle <= 2PI which should include 2PI already... Well maybe I will solve this mystery later.
Here I am just trying to understand basic lighting and material with old school opengl. My takeaway is that light and material together create the illusion of color and light through different combinations of RGB of the light and RGB of the material. Even for the reflection example below to make realistic, the color of the floor needs to be just right to go with the color of the ball. It is really more of an art than science but of course a revision of basic color theory is helpful!
Blending is used to create a 'fake' reflection