Pro OpenGL ES for iOS

CHAPTER 4: Turning On the Lights (^109)
Ambient Lighting
It’s time for some fun with the ambient lighting. Add the following line to initLighting()
then compile and run:
glLightfv(SS_SUNLIGHT,GL_AMBIENT,blue);
Does it look like Figure 4-10 (left)? And what should you do to get the image in Figure 4-
10 (right)? You need to add the following line:
glMaterialfv(GL_FRONT_AND_BACK, GL_AMBIENT, blue);
Figure 4-10. Blue ambient light only (left), both ambient light and ambient material (right)
Besides the ambient attribute for each light, you can also set a world ambient value. The
light-based values are variables, as are all of light parameters, so they vary as a function
of the distance, attenuation, and so on. The world value is a constant across your entire
OpenGL ES universe and can be set as follows:
GLfloat colorVector[4]={r,g,b,a};
glLightModelfv(GL_LIGHT_MODEL_AMBIENT,colorVector);
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