rotate with fixed lighting

I have 2 triangles and I’m rotating them. It seemed as if the lightsource didn’t rotate with them, so I rotated it explicitly, but still it looks weird. The upper triangle brightens up just before turning backward.

Here’s a video about it:

The code I tried:

void update(){
		glLoadIdentity(); //Reset the camera


		GLfloat lightPos0[] = {sin(angle+80.0), cos(angle+80.0), 0.1f, 1.0f};
		glLightfv(GL_LIGHT0, GL_POSITION, lightPos0);

		angle = angle + 0.03;

So basically my question is: should I rotate the lights explicitely?

sorry didnt read your post cearfully before so i deleted my post

I just write a reply to move it up in activity list.