message: add up vector value when missing
diff: @@ -357,8 +357,6 @@ void GLTFData::createLights()
  newLight->child("position").setValue(vec3f(0));
  if (newLight->hasChild("direction"))
  newLight->child("direction").setValue(vec3f(0.f, 0.f, -1.f));
  - if (newLight->hasChild("up"))
  - newLight->child("up").setValue(vec3f(0.f, 1.f, 0.f));
  // Color is optional, default:[1.0,1.0,1.0]
  auto lightColor = rgb(1.f);
  