for (int i = 0; i < triangles.length; i++) {
Triangle t = triangles[i];
r.pushMatrix();
Vector3D centerPoint = t.getCenterPointLocal();
r.translate(centerPoint.x, centerPoint.y, centerPoint.z);
r.scale(-2,-2,-2);
r.line(0, 0, 0, t.getNormalLocal().x, t.getNormalLocal().y, t.getNormalLocal().z);
r.popMatrix();
}
// for (int i = 0; i < normals.length; i++) {