Introduction - If you have any usage issues, please Google them yourself
(1) The first pot of color is blue, but there is no definition of light. No light teapot looks like the same objects in two dimensions, not three-dimensional feel (2) defines a second teapot blue light source direction GL_LIGHT0 (3) defines the third teapot two radiation sources, in addition to the direction of a blue light GL_LIGHT0, there is a gradual attenuation of the light intensity and the location of the yellow light GL_LIGHT1.