Materials

Basically, you use glColorMaterial to select material properties that should be changed when calling glColor.

So, when you do lighting you could do like this to set the diffuse material property like this:

glMaterialfv(GL_FRONT,GL_DIFFUSE,diffuse);

or, if you start by initializing like this:

glColorMaterial(GL_FRONT,GL_DIFFUSE);glEnable(GL_COLOR_MATERIAL);

you can then do the same with glColor:

glColor4fv(diffuse);

This can come in handy when using vertex arrays, for example, since there is no material array :)

It is also better to use glColorMaterial if you're not going to change many parameters each time. (It should be a bit faster, I think. And easier to read.)

Now it's clearer, so, It means that if I need two objects with the same color, but with different materials, I should switch glColorMaterial to the desidered one... let's say I have a "steel" red cube and a "plastic" red sphere... before rendering the second element, I need to change the glColorMaterial... but, if I have different objects with the same color and the same material, I can avoid glColorMaterial calling, is it right? Or better, I could initialize all my materials at the beginning associating them to a color, and then I could simply draw the scene with the correct color... am I right?