message: check vklComputeGradientV for NaNs
diff: @@ -56,5 +56,10 @@ inline vec3f Volume_getGradient(const Volume *uniform volume, const vec3f &P)
  vkl_vec3f result =
  vklComputeGradientV(volume->vklSampler, &((const vkl_vec3f &)P));
  + // TODO: remove it once VKL no longer returns sporadic NaNs
  + if (isnan(result.x)) result.x = 1.f;
  + if (isnan(result.y)) result.y = 1.f;
  + if (isnan(result.z)) result.z = 1.f;
  +
  return *((varying vec3f *)&result);
  }
  