Function gather_next_hits

tutorials/next_hit/next_hit_device.cpp:198–243

Filter callback function that gathers first N hits up to the first opaque surface */

/* Filter callback function that gathers first N hits up to the first opaque surface */
RTC_SYCL_INDIRECTLY_CALLABLE void gather_next_hits(const RTCFilterFunctionNArguments* args)
{
  assert(*args->valid == -1);
  RayQueryContext* context = (RayQueryContext*) args->context;
  HitList& hits = context->hits;
  RTCRay* ray = (RTCRay*) args->ray;
  RTCHit* hit = (RTCHit*) args->hit;
  assert(args->N == 1);
  args->valid[0] = 0; // ignore all hits

  /* avoid overflow of hits array */
  if (hits.end >= MAX_TOTAL_HITS) return;

  /* check if geometry is opaque */
  ISPCGeometry* geometry = (ISPCGeometry*) args->geometryUserPtr;
  bool opaque = !hits.data.enable_opacity || geometry->type != CURVES;
  
  HitList::Hit nhit(opaque, ray->tfar,hit->primID,hit->geomID,hit->instID[0]);

  /* ignore already found hits */
  if (hits.begin > 0 && nhit <= hits.hits[hits.begin-1])
    return;

  /* insert new hit at proper location */
  for (unsigned int i=hits.begin; i<hits.end; i++)
  {
    if (nhit < hits.hits[i]) {
      std::swap(nhit,hits.hits[i]);
      if (hits.hits[i].opaque) {
        hits.end = i+1;
        break;
      }
    }
  }

  /* store farthest hit if place left and last is not opaque */
  if (hits.size() < context->max_next_hits && hits.end < hits.data.max_total_hits && !hits.last_is_opaque())
    hits.hits[hits.end++] = nhit;

  /* shrink tfar when we collected sufficient hits for this pass, or the last hit is opaque */
  if (hits.size() == context->max_next_hits || hits.last_is_opaque())
  {
    ray->tfar = hits.last().t;
    args->valid[0] = -1; // accept hit
  }
}
  
/* gathers hits in multiple passes */
void multi_pass(const TutorialData& data, const Ray& ray_i, HitList& hits_o, int max_next_hits, RandomSampler& sampler, RayStats& stats, const RTCFeatureFlags feature_mask)