void keyboard(unsigned char key, int x, int y)
{
	switch (key) {
		case 27:		// tecla de escape termina o programa
			exit(0);
			break;
		case 97:{ // a
			light0x += incLuz;
			break;
				}
		case 115: // s
			light0y += incLuz;
			break;
		case 100: // d
			light0z += incLuz;
			break;
		case 9: // Tab = Altera Inc
			incLuz = incLuz*-1;
			break;
	}
}