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: http://www.youtube.com/watch?v=Dgc0k_hUcIY

The code I tried:


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

		gluLookAt
		(sin(angle)*3,cos(angle)*3,0.4,
		0.0,0.0,0.0,
		0.0,0.0,1.0);
		

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

		angle = angle + 0.03;
		glutPostRedisplay();
}

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.