void myMouse(int button, int state, int x, int y)
{
	y = screenHeight - y;

	switch (button) {
		case GLUT_LEFT_BUTTON:
			if (state == GLUT_DOWN) 
			{
				if(pointSet)
				{
					specialRayCoord.set(specialRayCoord.left, specialRayCoord.top, x, y);
					specialRayCoord.fix();
					doSpecRayTrace = 1;
					pointSet = 0;
					glutPostRedisplay();
				} else {
					specialRayCoord.set(x, y, 0, 0);
					pointSet = 1;
				}
			}
	}
}