message: Use new robust intersectBox. TODO: is robust intersectBox slower?
diff: #include "ospray/fb/Tile.ih"
  #include "ospray/render/Renderer.ih"
  #include "ospray/render/util.ih"
  +#include "ospray/common/Intersect.ih"
  unmasked void DR_default_computeRegionVisibility(
  DistributedRenderer *uniform self,
  @@ -91,15 +92,16 @@ unmasked void DR_default_computeRegionVisibility(
  for (uniform int r = 0; r < world->numRegions; ++r) {
  cif (!regionVisible[r] && !isEmpty(world->regions[r].bounds)) {
  - float t0, t1;
  - intersectBox(screenSample.ray, world->regions[r].bounds, t0, t1);
  - if (t0 < t1 && t0 >= screenSample.ray.t0
  - && t0 <= screenSample.ray.t) {
  + IntersectionValues isect = intersectBox(screenSample.ray.org, screenSample.ray.dir, world->regions[r].bounds);
  + if(isect.t_in.t_value < isect.t_out.t_value) {
  + if (and(and(isect.t_in.t_value > screenSample.ray.t0, isect.t_in.t_value < screenSample.ray.t),
  + isect.t_in.hit)) {
  regionVisible[r] = true;
  }
  }
  }
  }
  + }
  screenSample.rgb = make_vec3f(
  self->super.bgColor.x, self->super.bgColor.y, self->super.bgColor.z);
  