message: ParticleVolume generator: validate numParticles and set valueRange
diff: @@ -77,6 +77,8 @@ void ParticleVol::generateData()
  std::uniform_real_distribution<float> weightDistribution(
  weightRange.lower, weightRange.upper);
  + numParticles = std::max(1, numParticles);
  +
  position.resize(numParticles);
  radius.resize(numParticles);
  weight.resize(numParticles);
  @@ -91,6 +93,7 @@ void ParticleVol::generateData()
  auto &xfm = child("xfm");
  auto &tf = xfm.createChild("transferFunction", "transfer_function_jet");
  + tf["valueRange"] = vec2f(0.f, weightRange.upper);
  auto &pvol = tf.createChild("pvol", "volume_particle");
  pvol.createChild("gridOrigin", "vec3f", vec3f(-1.f));
  