message: use device pixel ratio in trackball panning
diff: @@ -227,8 +227,9 @@ namespace TrackballControls {
  Vec2.sub(panMouseChange, Vec2.copy(panMouseChange, _panEnd), _panStart);
  if (Vec2.squaredMagnitude(panMouseChange)) {
  - panMouseChange[0] *= (1 / camera.zoom) * camera.viewport.width * p.panSpeed;
  - panMouseChange[1] *= (1 / camera.zoom) * camera.viewport.height * p.panSpeed;
  + const factor = window.devicePixelRatio * p.panSpeed;
  + panMouseChange[0] *= (1 / camera.zoom) * camera.viewport.width * factor;
  + panMouseChange[1] *= (1 / camera.zoom) * camera.viewport.height * factor;
  Vec3.cross(panOffset, Vec3.copy(panOffset, _eye), camera.up);
  Vec3.setMagnitude(panOffset, panOffset, panMouseChange[0]);
  